<title>LLVM Assembly Language Reference Manual</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="author" content="Chris Lattner">
- <meta name="description"
+ <meta name="description"
content="LLVM Assembly Language Reference Manual.">
<link rel="stylesheet" href="llvm.css" type="text/css">
</head>
<li><a href="#highlevel">High Level Structure</a>
<ol>
<li><a href="#modulestructure">Module Structure</a></li>
- <li><a href="#linkage">Linkage Types</a></li>
+ <li><a href="#linkage">Linkage Types</a>
+ <ol>
+ <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
+ <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
+ <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
+ <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
+ <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
+ <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
+ <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
+ <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
+ <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
+ <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
+ <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
+ <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
+ <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
+ <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
+ </ol>
+ </li>
<li><a href="#callingconv">Calling Conventions</a></li>
<li><a href="#namedtypes">Named Types</a></li>
<li><a href="#globalvars">Global Variables</a></li>
<li><a href="#functionstructure">Functions</a></li>
<li><a href="#aliasstructure">Aliases</a></li>
+ <li><a href="#namedmetadatastructure">Named Metadata</a></li>
<li><a href="#paramattrs">Parameter Attributes</a></li>
<li><a href="#fnattrs">Function Attributes</a></li>
<li><a href="#gc">Garbage Collector Names</a></li>
<li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
<li><a href="#datalayout">Data Layout</a></li>
+ <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
</ol>
</li>
<li><a href="#typesystem">Type System</a>
<ol>
<li><a href="#t_classifications">Type Classifications</a></li>
- <li><a href="#t_primitive">Primitive Types</a>
+ <li><a href="#t_primitive">Primitive Types</a>
<ol>
+ <li><a href="#t_integer">Integer Type</a></li>
<li><a href="#t_floating">Floating Point Types</a></li>
<li><a href="#t_void">Void Type</a></li>
<li><a href="#t_label">Label Type</a></li>
</li>
<li><a href="#t_derived">Derived Types</a>
<ol>
- <li><a href="#t_integer">Integer Type</a></li>
<li><a href="#t_array">Array Type</a></li>
<li><a href="#t_function">Function Type</a></li>
<li><a href="#t_pointer">Pointer Type</a></li>
<li><a href="#complexconstants">Complex Constants</a></li>
<li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
<li><a href="#undefvalues">Undefined Values</a></li>
+ <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
<li><a href="#constantexprs">Constant Expressions</a></li>
- <li><a href="#metadata">Embedded Metadata</a></li>
</ol>
</li>
<li><a href="#othervalues">Other Values</a>
<ol>
<li><a href="#inlineasm">Inline Assembler Expressions</a></li>
+ <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
+ </ol>
+ </li>
+ <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
+ <ol>
+ <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
+ <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
+ Global Variable</a></li>
+ <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
+ Global Variable</a></li>
+ <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
+ Global Variable</a></li>
</ol>
</li>
<li><a href="#instref">Instruction Reference</a>
<li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
<li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
<li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
+ <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
<li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
<li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
<li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
</li>
<li><a href="#memoryops">Memory Access and Addressing Operations</a>
<ol>
- <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
- <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
<li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
<li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
<li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
<ol>
<li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
<li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
- <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
- <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
<li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
<li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
<li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
<li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
<li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
<li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
- <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
- <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
</ol>
</li>
<li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
<li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
</ol>
</li>
+ <li><a href="#int_memorymarkers">Memory Use Markers</a>
+ <ol>
+ <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
+ <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
+ <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
+ <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
+ </ol>
+ </li>
<li><a href="#int_general">General intrinsics</a>
<ol>
<li><a href="#int_var_annotation">
'<tt>llvm.trap</tt>' Intrinsic</a></li>
<li><a href="#int_stackprotector">
'<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
+ <li><a href="#int_objectsize">
+ '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
</ol>
</li>
</ol>
<!-- *********************************************************************** -->
<div class="doc_text">
-<p>This document is a reference manual for the LLVM assembly language.
-LLVM is a Static Single Assignment (SSA) based representation that provides
-type safety, low-level operations, flexibility, and the capability of
-representing 'all' high-level languages cleanly. It is the common code
-representation used throughout all phases of the LLVM compilation
-strategy.</p>
+
+<p>This document is a reference manual for the LLVM assembly language. LLVM is
+ a Static Single Assignment (SSA) based representation that provides type
+ safety, low-level operations, flexibility, and the capability of representing
+ 'all' high-level languages cleanly. It is the common code representation
+ used throughout all phases of the LLVM compilation strategy.</p>
+
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
-<p>The LLVM code representation is designed to be used in three
-different forms: as an in-memory compiler IR, as an on-disk bitcode
-representation (suitable for fast loading by a Just-In-Time compiler),
-and as a human readable assembly language representation. This allows
-LLVM to provide a powerful intermediate representation for efficient
-compiler transformations and analysis, while providing a natural means
-to debug and visualize the transformations. The three different forms
-of LLVM are all equivalent. This document describes the human readable
-representation and notation.</p>
+<p>The LLVM code representation is designed to be used in three different forms:
+ as an in-memory compiler IR, as an on-disk bitcode representation (suitable
+ for fast loading by a Just-In-Time compiler), and as a human readable
+ assembly language representation. This allows LLVM to provide a powerful
+ intermediate representation for efficient compiler transformations and
+ analysis, while providing a natural means to debug and visualize the
+ transformations. The three different forms of LLVM are all equivalent. This
+ document describes the human readable representation and notation.</p>
-<p>The LLVM representation aims to be light-weight and low-level
-while being expressive, typed, and extensible at the same time. It
-aims to be a "universal IR" of sorts, by being at a low enough level
-that high-level ideas may be cleanly mapped to it (similar to how
-microprocessors are "universal IR's", allowing many source languages to
-be mapped to them). By providing type information, LLVM can be used as
-the target of optimizations: for example, through pointer analysis, it
-can be proven that a C automatic variable is never accessed outside of
-the current function... allowing it to be promoted to a simple SSA
-value instead of a memory location.</p>
+<p>The LLVM representation aims to be light-weight and low-level while being
+ expressive, typed, and extensible at the same time. It aims to be a
+ "universal IR" of sorts, by being at a low enough level that high-level ideas
+ may be cleanly mapped to it (similar to how microprocessors are "universal
+ IR's", allowing many source languages to be mapped to them). By providing
+ type information, LLVM can be used as the target of optimizations: for
+ example, through pointer analysis, it can be proven that a C automatic
+ variable is never accessed outside of the current function, allowing it to
+ be promoted to a simple SSA value instead of a memory location.</p>
</div>
<div class="doc_text">
-<p>It is important to note that this document describes 'well formed'
-LLVM assembly language. There is a difference between what the parser
-accepts and what is considered 'well formed'. For example, the
-following instruction is syntactically okay, but not well formed:</p>
+<p>It is important to note that this document describes 'well formed' LLVM
+ assembly language. There is a difference between what the parser accepts and
+ what is considered 'well formed'. For example, the following instruction is
+ syntactically okay, but not well formed:</p>
<div class="doc_code">
<pre>
</pre>
</div>
-<p>...because the definition of <tt>%x</tt> does not dominate all of
-its uses. The LLVM infrastructure provides a verification pass that may
-be used to verify that an LLVM module is well formed. This pass is
-automatically run by the parser after parsing input assembly and by
-the optimizer before it outputs bitcode. The violations pointed out
-by the verifier pass indicate bugs in transformation passes or input to
-the parser.</p>
+<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
+ LLVM infrastructure provides a verification pass that may be used to verify
+ that an LLVM module is well formed. This pass is automatically run by the
+ parser after parsing input assembly and by the optimizer before it outputs
+ bitcode. The violations pointed out by the verifier pass indicate bugs in
+ transformation passes or input to the parser.</p>
+
</div>
<!-- Describe the typesetting conventions here. -->
<div class="doc_text">
- <p>LLVM identifiers come in two basic types: global and local. Global
- identifiers (functions, global variables) begin with the @ character. Local
- identifiers (register names, types) begin with the % character. Additionally,
- there are three different formats for identifiers, for different purposes:</p>
+<p>LLVM identifiers come in two basic types: global and local. Global
+ identifiers (functions, global variables) begin with the <tt>'@'</tt>
+ character. Local identifiers (register names, types) begin with
+ the <tt>'%'</tt> character. Additionally, there are three different formats
+ for identifiers, for different purposes:</p>
<ol>
<li>Named values are represented as a string of characters with their prefix.
- For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
- regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
- Identifiers which require other characters in their names can be surrounded
- with quotes. Special characters may be escaped using "\xx" where xx is the
- ASCII code for the character in hexadecimal. In this way, any character can
- be used in a name value, even quotes themselves.
+ For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
+ <tt>%a.really.long.identifier</tt>. The actual regular expression used is
+ '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
+ other characters in their names can be surrounded with quotes. Special
+ characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
+ ASCII code for the character in hexadecimal. In this way, any character
+ can be used in a name value, even quotes themselves.</li>
<li>Unnamed values are represented as an unsigned numeric value with their
- prefix. For example, %12, @2, %44.</li>
+ prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
<li>Constants, which are described in a <a href="#constants">section about
- constants</a>, below.</li>
+ constants</a>, below.</li>
</ol>
<p>LLVM requires that values start with a prefix for two reasons: Compilers
-don't need to worry about name clashes with reserved words, and the set of
-reserved words may be expanded in the future without penalty. Additionally,
-unnamed identifiers allow a compiler to quickly come up with a temporary
-variable without having to avoid symbol table conflicts.</p>
+ don't need to worry about name clashes with reserved words, and the set of
+ reserved words may be expanded in the future without penalty. Additionally,
+ unnamed identifiers allow a compiler to quickly come up with a temporary
+ variable without having to avoid symbol table conflicts.</p>
<p>Reserved words in LLVM are very similar to reserved words in other
-languages. There are keywords for different opcodes
-('<tt><a href="#i_add">add</a></tt>',
- '<tt><a href="#i_bitcast">bitcast</a></tt>',
- '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
-href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
-and others. These reserved words cannot conflict with variable names, because
-none of them start with a prefix character ('%' or '@').</p>
+ languages. There are keywords for different opcodes
+ ('<tt><a href="#i_add">add</a></tt>',
+ '<tt><a href="#i_bitcast">bitcast</a></tt>',
+ '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
+ ('<tt><a href="#t_void">void</a></tt>',
+ '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
+ reserved words cannot conflict with variable names, because none of them
+ start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
<p>Here is an example of LLVM code to multiply the integer variable
-'<tt>%X</tt>' by 8:</p>
+ '<tt>%X</tt>' by 8:</p>
<p>The easy way:</p>
<div class="doc_code">
<pre>
-<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
-<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
+
%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
+
%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
%result = <a href="#i_add">add</a> i32 %1, %1
</pre>
</div>
-<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
-important lexical features of LLVM:</p>
+<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
+ lexical features of LLVM:</p>
<ol>
-
<li>Comments are delimited with a '<tt>;</tt>' and go until the end of
- line.</li>
+ line.</li>
<li>Unnamed temporaries are created when the result of a computation is not
- assigned to a named value.</li>
+ assigned to a named value.</li>
<li>Unnamed temporaries are numbered sequentially</li>
-
</ol>
-<p>...and it also shows a convention that we follow in this document. When
-demonstrating instructions, we will follow an instruction with a comment that
-defines the type and name of value produced. Comments are shown in italic
-text.</p>
+<p>It also shows a convention that we follow in this document. When
+ demonstrating instructions, we will follow an instruction with a comment that
+ defines the type and name of value produced. Comments are shown in italic
+ text.</p>
</div>
<div class="doc_text">
-<p>LLVM programs are composed of "Module"s, each of which is a
-translation unit of the input programs. Each module consists of
-functions, global variables, and symbol table entries. Modules may be
-combined together with the LLVM linker, which merges function (and
-global variable) definitions, resolves forward declarations, and merges
-symbol table entries. Here is an example of the "hello world" module:</p>
+<p>LLVM programs are composed of "Module"s, each of which is a translation unit
+ of the input programs. Each module consists of functions, global variables,
+ and symbol table entries. Modules may be combined together with the LLVM
+ linker, which merges function (and global variable) definitions, resolves
+ forward declarations, and merges symbol table entries. Here is an example of
+ the "hello world" module:</p>
<div class="doc_code">
-<pre><i>; Declare the string constant as a global constant...</i>
-<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
- href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
+<pre>
+<i>; Declare the string constant as a global constant.</i>
+<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
<i>; External declaration of the puts function</i>
-<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
+<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
<i>; Definition of main function</i>
-define i32 @main() { <i>; i32()* </i>
- <i>; Convert [13 x i8]* to i8 *...</i>
- %cast210 = <a
- href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
+define i32 @main() { <i>; i32()* </i>
+ <i>; Convert [13 x i8]* to i8 *...</i>
+ %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
+
+ <i>; Call puts function to write out the string to stdout.</i>
+ <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
+ <a href="#i_ret">ret</a> i32 0<br>}
- <i>; Call puts function to write out the string to stdout...</i>
- <a
- href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
- <a
- href="#i_ret">ret</a> i32 0<br>}<br>
+<i>; Named metadata</i>
+!1 = metadata !{i32 41}
+!foo = !{!1, null}
</pre>
</div>
-<p>This example is made up of a <a href="#globalvars">global variable</a>
-named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
-function, and a <a href="#functionstructure">function definition</a>
-for "<tt>main</tt>".</p>
+<p>This example is made up of a <a href="#globalvars">global variable</a> named
+ "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
+ a <a href="#functionstructure">function definition</a> for
+ "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
+ "<tt>foo"</tt>.</p>
-<p>In general, a module is made up of a list of global values,
-where both functions and global variables are global values. Global values are
-represented by a pointer to a memory location (in this case, a pointer to an
-array of char, and a pointer to a function), and have one of the following <a
-href="#linkage">linkage types</a>.</p>
+<p>In general, a module is made up of a list of global values, where both
+ functions and global variables are global values. Global values are
+ represented by a pointer to a memory location (in this case, a pointer to an
+ array of char, and a pointer to a function), and have one of the
+ following <a href="#linkage">linkage types</a>.</p>
</div>
<div class="doc_text">
-<p>
-All Global Variables and Functions have one of the following types of linkage:
-</p>
+<p>All Global Variables and Functions have one of the following types of
+ linkage:</p>
<dl>
-
- <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
-
- <dd>Global values with private linkage are only directly accessible by
- objects in the current module. In particular, linking code into a module with
- an private global value may cause the private to be renamed as necessary to
- avoid collisions. Because the symbol is private to the module, all
- references can be updated. This doesn't show up in any symbol table in the
- object file.
- </dd>
-
- <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
-
- <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
- the case of ELF) in the object file. This corresponds to the notion of the
- '<tt>static</tt>' keyword in C.
- </dd>
-
- <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
- </dt>
-
+ <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
+ <dd>Global values with private linkage are only directly accessible by objects
+ in the current module. In particular, linking code into a module with an
+ private global value may cause the private to be renamed as necessary to
+ avoid collisions. Because the symbol is private to the module, all
+ references can be updated. This doesn't show up in any symbol table in the
+ object file.</dd>
+
+ <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
+ <dd>Similar to private, but the symbol is passed through the assembler and
+ removed by the linker after evaluation. Note that (unlike private
+ symbols) linker_private symbols are subject to coalescing by the linker:
+ weak symbols get merged and redefinitions are rejected. However, unlike
+ normal strong symbols, they are removed by the linker from the final
+ linked image (executable or dynamic library).</dd>
+
+ <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
+ <dd>Similar to private, but the value shows as a local symbol
+ (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
+ corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
+
+ <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
<dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
- into the object file corresponding to the LLVM module. They exist to
- allow inlining and other optimizations to take place given knowledge of the
- definition of the global, which is known to be somewhere outside the module.
- Globals with <tt>available_externally</tt> linkage are allowed to be discarded
- at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
- type is only allowed on definitions, not declarations.</dd>
-
- <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
-
+ into the object file corresponding to the LLVM module. They exist to
+ allow inlining and other optimizations to take place given knowledge of
+ the definition of the global, which is known to be somewhere outside the
+ module. Globals with <tt>available_externally</tt> linkage are allowed to
+ be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
+ This linkage type is only allowed on definitions, not declarations.</dd>
+
+ <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
<dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
- the same name when linkage occurs. This is typically used to implement
- inline functions, templates, or other code which must be generated in each
- translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
- allowed to be discarded.
- </dd>
-
- <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
-
- <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
- linkage, except that unreferenced <tt>common</tt> globals may not be
- discarded. This is used for globals that may be emitted in multiple
- translation units, but that are not guaranteed to be emitted into every
- translation unit that uses them. One example of this is tentative
- definitions in C, such as "<tt>int X;</tt>" at global scope.
- </dd>
-
- <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
-
- <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
- that some targets may choose to emit different assembly sequences for them
- for target-dependent reasons. This is used for globals that are declared
- "weak" in C source code.
- </dd>
-
- <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
-
+ the same name when linkage occurs. This can be used to implement
+ some forms of inline functions, templates, or other code which must be
+ generated in each translation unit that uses it, but where the body may
+ be overridden with a more definitive definition later. Unreferenced
+ <tt>linkonce</tt> globals are allowed to be discarded. Note that
+ <tt>linkonce</tt> linkage does not actually allow the optimizer to
+ inline the body of this function into callers because it doesn't know if
+ this definition of the function is the definitive definition within the
+ program or whether it will be overridden by a stronger definition.
+ To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
+ linkage.</dd>
+
+ <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
+ <dd>"<tt>weak</tt>" linkage has the same merging semantics as
+ <tt>linkonce</tt> linkage, except that unreferenced globals with
+ <tt>weak</tt> linkage may not be discarded. This is used for globals that
+ are declared "weak" in C source code.</dd>
+
+ <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
+ <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
+ they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
+ global scope.
+ Symbols with "<tt>common</tt>" linkage are merged in the same way as
+ <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
+ <tt>common</tt> symbols may not have an explicit section,
+ must have a zero initializer, and may not be marked '<a
+ href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
+ have common linkage.</dd>
+
+
+ <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
<dd>"<tt>appending</tt>" linkage may only be applied to global variables of
- pointer to array type. When two global variables with appending linkage are
- linked together, the two global arrays are appended together. This is the
- LLVM, typesafe, equivalent of having the system linker append together
- "sections" with identical names when .o files are linked.
- </dd>
-
- <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
-
- <dd>The semantics of this linkage follow the ELF object file model: the
- symbol is weak until linked, if not linked, the symbol becomes null instead
- of being an undefined reference.
- </dd>
-
- <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
- <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
- <dd>Some languages allow differing globals to be merged, such as two
- functions with different semantics. Other languages, such as <tt>C++</tt>,
- ensure that only equivalent globals are ever merged (the "one definition
- rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
- and <tt>weak_odr</tt> linkage types to indicate that the global will only
- be merged with equivalent globals. These linkage types are otherwise the
- same as their non-<tt>odr</tt> versions.
- </dd>
+ pointer to array type. When two global variables with appending linkage
+ are linked together, the two global arrays are appended together. This is
+ the LLVM, typesafe, equivalent of having the system linker append together
+ "sections" with identical names when .o files are linked.</dd>
+
+ <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
+ <dd>The semantics of this linkage follow the ELF object file model: the symbol
+ is weak until linked, if not linked, the symbol becomes null instead of
+ being an undefined reference.</dd>
+
+ <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
+ <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
+ <dd>Some languages allow differing globals to be merged, such as two functions
+ with different semantics. Other languages, such as <tt>C++</tt>, ensure
+ that only equivalent globals are ever merged (the "one definition rule" -
+ "ODR"). Such languages can use the <tt>linkonce_odr</tt>
+ and <tt>weak_odr</tt> linkage types to indicate that the global will only
+ be merged with equivalent globals. These linkage types are otherwise the
+ same as their non-<tt>odr</tt> versions.</dd>
<dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
-
<dd>If none of the above identifiers are used, the global is externally
- visible, meaning that it participates in linkage and can be used to resolve
- external symbol references.
- </dd>
+ visible, meaning that it participates in linkage and can be used to
+ resolve external symbol references.</dd>
</dl>
- <p>
- The next two types of linkage are targeted for Microsoft Windows platform
- only. They are designed to support importing (exporting) symbols from (to)
- DLLs (Dynamic Link Libraries).
- </p>
-
- <dl>
- <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
+<p>The next two types of linkage are targeted for Microsoft Windows platform
+ only. They are designed to support importing (exporting) symbols from (to)
+ DLLs (Dynamic Link Libraries).</p>
+<dl>
+ <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
<dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
- or variable via a global pointer to a pointer that is set up by the DLL
- exporting the symbol. On Microsoft Windows targets, the pointer name is
- formed by combining <code>__imp_</code> and the function or variable name.
- </dd>
-
- <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
+ or variable via a global pointer to a pointer that is set up by the DLL
+ exporting the symbol. On Microsoft Windows targets, the pointer name is
+ formed by combining <code>__imp_</code> and the function or variable
+ name.</dd>
+ <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
<dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
- pointer to a pointer in a DLL, so that it can be referenced with the
- <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
- name is formed by combining <code>__imp_</code> and the function or variable
- name.
- </dd>
-
+ pointer to a pointer in a DLL, so that it can be referenced with the
+ <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
+ name is formed by combining <code>__imp_</code> and the function or
+ variable name.</dd>
</dl>
-<p>For example, since the "<tt>.LC0</tt>"
-variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
-variable and was linked with this one, one of the two would be renamed,
-preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
-external (i.e., lacking any linkage declarations), they are accessible
-outside of the current module.</p>
-<p>It is illegal for a function <i>declaration</i>
-to have any linkage type other than "externally visible", <tt>dllimport</tt>
-or <tt>extern_weak</tt>.</p>
+<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
+ another module defined a "<tt>.LC0</tt>" variable and was linked with this
+ one, one of the two would be renamed, preventing a collision. Since
+ "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
+ declarations), they are accessible outside of the current module.</p>
+
+<p>It is illegal for a function <i>declaration</i> to have any linkage type
+ other than "externally visible", <tt>dllimport</tt>
+ or <tt>extern_weak</tt>.</p>
+
<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
-or <tt>weak_odr</tt> linkages.</p>
+ or <tt>weak_odr</tt> linkages.</p>
+
</div>
<!-- ======================================================================= -->
<div class="doc_text">
<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
-and <a href="#i_invoke">invokes</a> can all have an optional calling convention
-specified for the call. The calling convention of any pair of dynamic
-caller/callee must match, or the behavior of the program is undefined. The
-following calling conventions are supported by LLVM, and more may be added in
-the future:</p>
+ and <a href="#i_invoke">invokes</a> can all have an optional calling
+ convention specified for the call. The calling convention of any pair of
+ dynamic caller/callee must match, or the behavior of the program is
+ undefined. The following calling conventions are supported by LLVM, and more
+ may be added in the future:</p>
<dl>
<dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
-
<dd>This calling convention (the default if no other calling convention is
- specified) matches the target C calling conventions. This calling convention
- supports varargs function calls and tolerates some mismatch in the declared
- prototype and implemented declaration of the function (as does normal C).
- </dd>
+ specified) matches the target C calling conventions. This calling
+ convention supports varargs function calls and tolerates some mismatch in
+ the declared prototype and implemented declaration of the function (as
+ does normal C).</dd>
<dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
-
<dd>This calling convention attempts to make calls as fast as possible
- (e.g. by passing things in registers). This calling convention allows the
- target to use whatever tricks it wants to produce fast code for the target,
- without having to conform to an externally specified ABI (Application Binary
- Interface). Implementations of this convention should allow arbitrary
- <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
- supported. This calling convention does not support varargs and requires the
- prototype of all callees to exactly match the prototype of the function
- definition.
- </dd>
+ (e.g. by passing things in registers). This calling convention allows the
+ target to use whatever tricks it wants to produce fast code for the
+ target, without having to conform to an externally specified ABI
+ (Application Binary Interface).
+ <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
+ when this convention is used.</a> This calling convention does not
+ support varargs and requires the prototype of all callees to exactly match
+ the prototype of the function definition.</dd>
<dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
-
<dd>This calling convention attempts to make code in the caller as efficient
- as possible under the assumption that the call is not commonly executed. As
- such, these calls often preserve all registers so that the call does not break
- any live ranges in the caller side. This calling convention does not support
- varargs and requires the prototype of all callees to exactly match the
- prototype of the function definition.
- </dd>
+ as possible under the assumption that the call is not commonly executed.
+ As such, these calls often preserve all registers so that the call does
+ not break any live ranges in the caller side. This calling convention
+ does not support varargs and requires the prototype of all callees to
+ exactly match the prototype of the function definition.</dd>
<dt><b>"<tt>cc <<em>n</em>></tt>" - Numbered convention</b>:</dt>
-
<dd>Any calling convention may be specified by number, allowing
- target-specific calling conventions to be used. Target specific calling
- conventions start at 64.
- </dd>
+ target-specific calling conventions to be used. Target specific calling
+ conventions start at 64.</dd>
</dl>
<p>More calling conventions can be added/defined on an as-needed basis, to
-support pascal conventions or any other well-known target-independent
-convention.</p>
+ support Pascal conventions or any other well-known target-independent
+ convention.</p>
</div>
<div class="doc_text">
-<p>
-All Global Variables and Functions have one of the following visibility styles:
-</p>
+<p>All Global Variables and Functions have one of the following visibility
+ styles:</p>
<dl>
<dt><b>"<tt>default</tt>" - Default style</b>:</dt>
-
<dd>On targets that use the ELF object file format, default visibility means
- that the declaration is visible to other
- modules and, in shared libraries, means that the declared entity may be
- overridden. On Darwin, default visibility means that the declaration is
- visible to other modules. Default visibility corresponds to "external
- linkage" in the language.
- </dd>
+ that the declaration is visible to other modules and, in shared libraries,
+ means that the declared entity may be overridden. On Darwin, default
+ visibility means that the declaration is visible to other modules. Default
+ visibility corresponds to "external linkage" in the language.</dd>
<dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
-
<dd>Two declarations of an object with hidden visibility refer to the same
- object if they are in the same shared object. Usually, hidden visibility
- indicates that the symbol will not be placed into the dynamic symbol table,
- so no other module (executable or shared library) can reference it
- directly.
- </dd>
+ object if they are in the same shared object. Usually, hidden visibility
+ indicates that the symbol will not be placed into the dynamic symbol
+ table, so no other module (executable or shared library) can reference it
+ directly.</dd>
<dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
-
<dd>On ELF, protected visibility indicates that the symbol will be placed in
- the dynamic symbol table, but that references within the defining module will
- bind to the local symbol. That is, the symbol cannot be overridden by another
- module.
- </dd>
+ the dynamic symbol table, but that references within the defining module
+ will bind to the local symbol. That is, the symbol cannot be overridden by
+ another module.</dd>
</dl>
</div>
<div class="doc_text">
<p>LLVM IR allows you to specify name aliases for certain types. This can make
-it easier to read the IR and make the IR more condensed (particularly when
-recursive types are involved). An example of a name specification is:
-</p>
+ it easier to read the IR and make the IR more condensed (particularly when
+ recursive types are involved). An example of a name specification is:</p>
<div class="doc_code">
<pre>
</pre>
</div>
-<p>You may give a name to any <a href="#typesystem">type</a> except "<a
-href="t_void">void</a>". Type name aliases may be used anywhere a type is
-expected with the syntax "%mytype".</p>
+<p>You may give a name to any <a href="#typesystem">type</a> except
+ "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
+ is expected with the syntax "%mytype".</p>
<p>Note that type names are aliases for the structural type that they indicate,
-and that you can therefore specify multiple names for the same type. This often
-leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
-structural typing, the name is not part of the type. When printing out LLVM IR,
-the printer will pick <em>one name</em> to render all types of a particular
-shape. This means that if you have code where two different source types end up
-having the same LLVM type, that the dumper will sometimes print the "wrong" or
-unexpected type. This is an important design point and isn't going to
-change.</p>
+ and that you can therefore specify multiple names for the same type. This
+ often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
+ uses structural typing, the name is not part of the type. When printing out
+ LLVM IR, the printer will pick <em>one name</em> to render all types of a
+ particular shape. This means that if you have code where two different
+ source types end up having the same LLVM type, that the dumper will sometimes
+ print the "wrong" or unexpected type. This is an important design point and
+ isn't going to change.</p>
</div>
<div class="doc_text">
<p>Global variables define regions of memory allocated at compilation time
-instead of run-time. Global variables may optionally be initialized, may have
-an explicit section to be placed in, and may have an optional explicit alignment
-specified. A variable may be defined as "thread_local", which means that it
-will not be shared by threads (each thread will have a separated copy of the
-variable). A variable may be defined as a global "constant," which indicates
-that the contents of the variable will <b>never</b> be modified (enabling better
-optimization, allowing the global data to be placed in the read-only section of
-an executable, etc). Note that variables that need runtime initialization
-cannot be marked "constant" as there is a store to the variable.</p>
-
-<p>
-LLVM explicitly allows <em>declarations</em> of global variables to be marked
-constant, even if the final definition of the global is not. This capability
-can be used to enable slightly better optimization of the program, but requires
-the language definition to guarantee that optimizations based on the
-'constantness' are valid for the translation units that do not include the
-definition.
-</p>
-
-<p>As SSA values, global variables define pointer values that are in
-scope (i.e. they dominate) all basic blocks in the program. Global
-variables always define a pointer to their "content" type because they
-describe a region of memory, and all memory objects in LLVM are
-accessed through pointers.</p>
-
-<p>A global variable may be declared to reside in a target-specifc numbered
-address space. For targets that support them, address spaces may affect how
-optimizations are performed and/or what target instructions are used to access
-the variable. The default address space is zero. The address space qualifier
-must precede any other attributes.</p>
+ instead of run-time. Global variables may optionally be initialized, may
+ have an explicit section to be placed in, and may have an optional explicit
+ alignment specified. A variable may be defined as "thread_local", which
+ means that it will not be shared by threads (each thread will have a
+ separated copy of the variable). A variable may be defined as a global
+ "constant," which indicates that the contents of the variable
+ will <b>never</b> be modified (enabling better optimization, allowing the
+ global data to be placed in the read-only section of an executable, etc).
+ Note that variables that need runtime initialization cannot be marked
+ "constant" as there is a store to the variable.</p>
+
+<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
+ constant, even if the final definition of the global is not. This capability
+ can be used to enable slightly better optimization of the program, but
+ requires the language definition to guarantee that optimizations based on the
+ 'constantness' are valid for the translation units that do not include the
+ definition.</p>
+
+<p>As SSA values, global variables define pointer values that are in scope
+ (i.e. they dominate) all basic blocks in the program. Global variables
+ always define a pointer to their "content" type because they describe a
+ region of memory, and all memory objects in LLVM are accessed through
+ pointers.</p>
+
+<p>A global variable may be declared to reside in a target-specific numbered
+ address space. For targets that support them, address spaces may affect how
+ optimizations are performed and/or what target instructions are used to
+ access the variable. The default address space is zero. The address space
+ qualifier must precede any other attributes.</p>
<p>LLVM allows an explicit section to be specified for globals. If the target
-supports it, it will emit globals to the section specified.</p>
+ supports it, it will emit globals to the section specified.</p>
<p>An explicit alignment may be specified for a global. If not present, or if
-the alignment is set to zero, the alignment of the global is set by the target
-to whatever it feels convenient. If an explicit alignment is specified, the
-global is forced to have at least that much alignment. All alignments must be
-a power of 2.</p>
+ the alignment is set to zero, the alignment of the global is set by the
+ target to whatever it feels convenient. If an explicit alignment is
+ specified, the global is forced to have at least that much alignment. All
+ alignments must be a power of 2.</p>
-<p>For example, the following defines a global in a numbered address space with
-an initializer, section, and alignment:</p>
+<p>For example, the following defines a global in a numbered address space with
+ an initializer, section, and alignment:</p>
<div class="doc_code">
<pre>
<div class="doc_text">
-<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
-an optional <a href="#linkage">linkage type</a>, an optional
-<a href="#visibility">visibility style</a>, an optional
-<a href="#callingconv">calling convention</a>, a return type, an optional
-<a href="#paramattrs">parameter attribute</a> for the return type, a function
-name, a (possibly empty) argument list (each with optional
-<a href="#paramattrs">parameter attributes</a>), optional
-<a href="#fnattrs">function attributes</a>, an optional section,
-an optional alignment, an optional <a href="#gc">garbage collector name</a>,
-an opening curly brace, a list of basic blocks, and a closing curly brace.
+<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
+ optional <a href="#linkage">linkage type</a>, an optional
+ <a href="#visibility">visibility style</a>, an optional
+
<a href="#callingconv">calling convention</a>, a return type, an optional
+ <a href="#paramattrs">parameter attribute</a> for the return type, a function
+ name, a (possibly empty) argument list (each with optional
+ <a href="#paramattrs">parameter attributes</a>), optional
+ <a href="#fnattrs">function attributes</a>, an optional section, an optional
+ alignment, an optional <a href="#gc">garbage collector name</a>, an opening
+ curly brace, a list of basic blocks, and a closing curly brace.</p>
-LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
-optional <a href="#linkage">linkage type</a>, an optional
-<a href="#visibility">visibility style</a>, an optional
-<a href="#callingconv">calling convention</a>, a return type, an optional
-<a href="#paramattrs">parameter attribute</a> for the return type, a function
-name, a possibly empty list of arguments, an optional alignment, and an optional
-<a href="#gc">garbage collector name</a>.</p>
+<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
+
optional <a href="#linkage">linkage type</a>, an optional
+ <a href="#visibility">visibility style</a>, an optional
+
<a href="#callingconv">calling convention</a>, a return type, an optional
+ <a href="#paramattrs">parameter attribute</a> for the return type, a function
+ name, a possibly empty list of arguments, an optional alignment, and an
+
optional <a href="#gc">garbage collector name</a>.</p>
<p>A function definition contains a list of basic blocks, forming the CFG
-(Control Flow Graph) for
-the function. Each basic block may optionally start with a label (giving the
-basic block a symbol table entry), contains a list of instructions, and ends
-with a <a href="#terminators">terminator</a> instruction (such as a branch or
-function return).</p>
+ (Control Flow Graph) for the function. Each basic block may optionally start
+ with a label (giving the basic block a symbol table entry), contains a list
+ of instructions, and ends with a <a href="#terminators">terminator</a>
+ instruction (such as a branch or function return).</p>
<p>The first basic block in a function is special in two ways: it is immediately
-executed on entrance to the function, and it is not allowed to have predecessor
-basic blocks (i.e. there can not be any branches to the entry block of a
-function). Because the block can have no predecessors, it also cannot have any
-<a href="#i_phi">PHI nodes</a>.</p>
+ executed on entrance to the function, and it is not allowed to have
+ predecessor basic blocks (i.e. there can not be any branches to the entry
+ block of a function). Because the block can have no predecessors, it also
+
cannot have any <a href="#i_phi">PHI nodes</a>.</p>
<p>LLVM allows an explicit section to be specified for functions. If the target
-supports it, it will emit functions to the section specified.</p>
+ supports it, it will emit functions to the section specified.</p>
<p>An explicit alignment may be specified for a function. If not present, or if
-the alignment is set to zero, the alignment of the function is set by the target
-to whatever it feels convenient. If an explicit alignment is specified, the
-function is forced to have at least that much alignment. All alignments must be
-a power of 2.</p>
-
- <h5>Syntax:</h5>
+ the alignment is set to zero, the alignment of the function is set by the
+ target to whatever it feels convenient. If an explicit alignment is
+ specified, the function is forced to have at least that much alignment. All
+ alignments must be a power of 2.</p>
+<h5>Syntax:</h5>
<div class="doc_code">
-<tt>
+<pre>
define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
- [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
- <ResultType> @<FunctionName> ([argument list])
- [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
- [<a href="#gc">gc</a>] { ... }
-</tt>
+
[<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
+ <ResultType> @<FunctionName> ([argument list])
+
[<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
+
[<a href="#gc">gc</a>] { ... }
+</pre>
</div>
</div>
-
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="aliasstructure">Aliases</a>
</div>
+
<div class="doc_text">
- <p>Aliases act as "second name" for the aliasee value (which can be either
- function, global variable, another alias or bitcast of global value). Aliases
- may have an optional <a href="#linkage">linkage type</a>, and an
- optional <a href="#visibility">visibility style</a>.</p>
- <h5>Syntax:</h5>
+<p>Aliases act as "second name" for the aliasee value (which can be either
+ function, global variable, another alias or bitcast of global value). Aliases
+ may have an optional <a href="#linkage">linkage type</a>, and an
+ optional <a href="#visibility">visibility style</a>.</p>
+<h5>Syntax:</h5>
<div class="doc_code">
<pre>
@<Name> = alias [Linkage] [Visibility] <AliaseeTy> @<Aliasee>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="namedmetadatastructure">Named Metadata</a>
+</div>
+
+<div class="doc_text">
+
+<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
+ nodes</a> (but not metadata strings) and null are the only valid operands for
+ a named metadata.</p>
+
+<h5>Syntax:</h5>
+<div class="doc_code">
+<pre>
+!1 = metadata !{metadata !"one"}
+!name = !{null, !1}
+</pre>
+</div>
+</div>
<!-- ======================================================================= -->
<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
+
<div class="doc_text">
- <p>The return type and each parameter of a function type may have a set of
- <i>parameter attributes</i> associated with them. Parameter attributes are
- used to communicate additional information about the result or parameters of
- a function. Parameter attributes are considered to be part of the function,
- not of the function type, so functions with different parameter attributes
- can have the same function type.</p>
- <p>Parameter attributes are simple keywords that follow the type specified. If
- multiple parameter attributes are needed, they are space separated. For
- example:</p>
+<p>The return type and each parameter of a function type may have a set of
+ <i>parameter attributes</i> associated with them. Parameter attributes are
+ used to communicate additional information about the result or parameters of
+ a function. Parameter attributes are considered to be part of the function,
+ not of the function type, so functions with different parameter attributes
+ can have the same function type.</p>
+
+<p>Parameter attributes are simple keywords that follow the type specified. If
+ multiple parameter attributes are needed, they are space separated. For
+ example:</p>
<div class="doc_code">
<pre>
</pre>
</div>
- <p>Note that any attributes for the function result (<tt>nounwind</tt>,
- <tt>readonly</tt>) come immediately after the argument list.</p>
-
- <p>Currently, only the following parameter attributes are defined:</p>
- <dl>
- <dt><tt>zeroext</tt></dt>
- <dd>This indicates to the code generator that the parameter or return value
- should be zero-extended to a 32-bit value by the caller (for a parameter)
- or the callee (for a return value).</dd>
-
- <dt><tt>signext</tt></dt>
- <dd>This indicates to the code generator that the parameter or return value
- should be sign-extended to a 32-bit value by the caller (for a parameter)
- or the callee (for a return value).</dd>
-
- <dt><tt>inreg</tt></dt>
- <dd>This indicates that this parameter or return value should be treated
- in a special target-dependent fashion during while emitting code for a
- function call or return (usually, by putting it in a register as opposed
- to memory, though some targets use it to distinguish between two different
- kinds of registers). Use of this attribute is target-specific.</dd>
-
- <dt><tt><a name="byval">byval</a></tt></dt>
- <dd>This indicates that the pointer parameter should really be passed by
- value to the function. The attribute implies that a hidden copy of the
- pointee is made between the caller and the callee, so the callee is unable
- to modify the value in the callee. This attribute is only valid on LLVM
- pointer arguments. It is generally used to pass structs and arrays by
- value, but is also valid on pointers to scalars. The copy is considered to
- belong to the caller not the callee (for example,
- <tt><a href="#readonly">readonly</a></tt> functions should not write to
- <tt>byval</tt> parameters). This is not a valid attribute for return
- values. The byval attribute also supports specifying an alignment with the
- align attribute. This has a target-specific effect on the code generator
- that usually indicates a desired alignment for the synthesized stack
- slot.</dd>
-
- <dt><tt>sret</tt></dt>
- <dd>This indicates that the pointer parameter specifies the address of a
- structure that is the return value of the function in the source program.
- This pointer must be guaranteed by the caller to be valid: loads and stores
- to the structure may be assumed by the callee to not to trap. This may only
- be applied to the first parameter. This is not a valid attribute for
- return values. </dd>
-
- <dt><tt>noalias</tt></dt>
- <dd>This indicates that the pointer does not alias any global or any other
- parameter. The caller is responsible for ensuring that this is the
- case. On a function return value, <tt>noalias</tt> additionally indicates
- that the pointer does not alias any other pointers visible to the
- caller. For further details, please see the discussion of the NoAlias
- response in
- <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
- analysis</a>.</dd>
-
- <dt><tt>nocapture</tt></dt>
- <dd>This indicates that the callee does not make any copies of the pointer
- that outlive the callee itself. This is not a valid attribute for return
- values.</dd>
-
- <dt><tt>nest</tt></dt>
- <dd>This indicates that the pointer parameter can be excised using the
- <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
- attribute for return values.</dd>
- </dl>
+<p>Note that any attributes for the function result (<tt>nounwind</tt>,
+ <tt>readonly</tt>) come immediately after the argument list.</p>
+
+<p>Currently, only the following parameter attributes are defined:</p>
+
+<dl>
+ <dt><tt><b>zeroext</b></tt></dt>
+ <dd>This indicates to the code generator that the parameter or return value
+ should be zero-extended to a 32-bit value by the caller (for a parameter)
+ or the callee (for a return value).</dd>
+
+ <dt><tt><b>signext</b></tt></dt>
+ <dd>This indicates to the code generator that the parameter or return value
+ should be sign-extended to a 32-bit value by the caller (for a parameter)
+ or the callee (for a return value).</dd>
+
+ <dt><tt><b>inreg</b></tt></dt>
+ <dd>This indicates that this parameter or return value should be treated in a
+ special target-dependent fashion during while emitting code for a function
+ call or return (usually, by putting it in a register as opposed to memory,
+ though some targets use it to distinguish between two different kinds of
+ registers). Use of this attribute is target-specific.</dd>
+
+ <dt><tt><b><a name="byval">byval</a></b></tt></dt>
+ <dd>This indicates that the pointer parameter should really be passed by value
+ to the function. The attribute implies that a hidden copy of the pointee
+ is made between the caller and the callee, so the callee is unable to
+ modify the value in the callee. This attribute is only valid on LLVM
+ pointer arguments. It is generally used to pass structs and arrays by
+ value, but is also valid on pointers to scalars. The copy is considered
+ to belong to the caller not the callee (for example,
+ <tt><a href="#readonly">readonly</a></tt> functions should not write to
+ <tt>byval</tt> parameters). This is not a valid attribute for return
+ values. The byval attribute also supports specifying an alignment with
+ the align attribute. This has a target-specific effect on the code
+ generator that usually indicates a desired alignment for the synthesized
+ stack slot.</dd>
+
+ <dt><tt><b>sret</b></tt></dt>
+ <dd>This indicates that the pointer parameter specifies the address of a
+ structure that is the return value of the function in the source program.
+ This pointer must be guaranteed by the caller to be valid: loads and
+ stores to the structure may be assumed by the callee to not to trap. This
+ may only be applied to the first parameter. This is not a valid attribute
+ for return values. </dd>
+
+ <dt><tt><b>noalias</b></tt></dt>
+ <dd>This indicates that the pointer does not alias any global or any other
+ parameter. The caller is responsible for ensuring that this is the
+ case. On a function return value, <tt>noalias</tt> additionally indicates
+ that the pointer does not alias any other pointers visible to the
+ caller. For further details, please see the discussion of the NoAlias
+ response in
+ <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
+ analysis</a>.</dd>
+
+ <dt><tt><b>nocapture</b></tt></dt>
+ <dd>This indicates that the callee does not make any copies of the pointer
+ that outlive the callee itself. This is not a valid attribute for return
+ values.</dd>
+
+ <dt><tt><b>nest</b></tt></dt>
+ <dd>This indicates that the pointer parameter can be excised using the
+ <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
+ attribute for return values.</dd>
+</dl>
</div>
</div>
<div class="doc_text">
+
<p>Each function may specify a garbage collector name, which is simply a
-string.</p>
+ string:</p>
-<div class="doc_code"><pre
->define void @f() gc "name" { ...</pre></div>
+<div class="doc_code">
+<pre>
+define void @f() gc "name" { ... }
+</pre>
+</div>
<p>The compiler declares the supported values of <i>name</i>. Specifying a
-collector which will cause the compiler to alter its output in order to support
-the named garbage collection algorithm.</p>
+ collector which will cause the compiler to alter its output in order to
+ support the named garbage collection algorithm.</p>
+
</div>
<!-- ======================================================================= -->
<div class="doc_text">
-<p>Function attributes are set to communicate additional information about
- a function. Function attributes are considered to be part of the function,
- not of the function type, so functions with different parameter attributes
- can have the same function type.</p>
+<p>Function attributes are set to communicate additional information about a
+ function. Function attributes are considered to be part of the function, not
+ of the function type, so functions with different parameter attributes can
+ have the same function type.</p>
- <p>Function attributes are simple keywords that follow the type specified. If
- multiple attributes are needed, they are space separated. For
- example:</p>
+<p>Function attributes are simple keywords that follow the type specified. If
+ multiple attributes are needed, they are space separated. For example:</p>
<div class="doc_code">
<pre>
define void @f() noinline { ... }
define void @f() alwaysinline { ... }
define void @f() alwaysinline optsize { ... }
-define void @f() optsize
+define void @f() optsize { ... }
</pre>
</div>
<dl>
-<dt><tt>alwaysinline</tt></dt>
-<dd>This attribute indicates that the inliner should attempt to inline this
-function into callers whenever possible, ignoring any active inlining size
-threshold for this caller.</dd>
-
-<dt><tt>noinline</tt></dt>
-<dd>This attribute indicates that the inliner should never inline this function
-in any situation. This attribute may not be used together with the
-<tt>alwaysinline</tt> attribute.</dd>
-
-<dt><tt>optsize</tt></dt>
-<dd>This attribute suggests that optimization passes and code generator passes
-make choices that keep the code size of this function low, and otherwise do
-optimizations specifically to reduce code size.</dd>
-
-<dt><tt>noreturn</tt></dt>
-<dd>This function attribute indicates that the function never returns normally.
-This produces undefined behavior at runtime if the function ever does
-dynamically return.</dd>
-
-<dt><tt>nounwind</tt></dt>
-<dd>This function attribute indicates that the function never returns with an
-unwind or exceptional control flow. If the function does unwind, its runtime
-behavior is undefined.</dd>
-
-<dt><tt>readnone</tt></dt>
-<dd>This attribute indicates that the function computes its result (or decides to
-unwind an exception) based strictly on its arguments, without dereferencing any
-pointer arguments or otherwise accessing any mutable state (e.g. memory, control
-registers, etc) visible to caller functions. It does not write through any
-pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
-never changes any state visible to callers. This means that it cannot unwind
-exceptions by calling the <tt>C++</tt> exception throwing methods, but could
-use the <tt>unwind</tt> instruction.</dd>
-
-<dt><tt><a name="readonly">readonly</a></tt></dt>
-<dd>This attribute indicates that the function does not write through any
-pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
-or otherwise modify any state (e.g. memory, control registers, etc) visible to
-caller functions. It may dereference pointer arguments and read state that may
-be set in the caller. A readonly function always returns the same value (or
-unwinds an exception identically) when called with the same set of arguments
-and global state. It cannot unwind an exception by calling the <tt>C++</tt>
-exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
-
-<dt><tt><a name="ssp">ssp</a></tt></dt>
-<dd>This attribute indicates that the function should emit a stack smashing
-protector. It is in the form of a "canary"—a random value placed on the
-stack before the local variables that's checked upon return from the function to
-see if it has been overwritten. A heuristic is used to determine if a function
-needs stack protectors or not.
-
-<br><br>If a function that has an <tt>ssp</tt> attribute is inlined into a function
-that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
-have an <tt>ssp</tt> attribute.</dd>
-
-<dt><tt>sspreq</tt></dt>
-<dd>This attribute indicates that the function should <em>always</em> emit a
-stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
-function attribute.
-
-If a function that has an <tt>sspreq</tt> attribute is inlined into a
-function that doesn't have an <tt>sspreq</tt> attribute or which has
-an <tt>ssp</tt> attribute, then the resulting function will have
-an <tt>sspreq</tt> attribute.</dd>
-
-<dt><tt>noredzone</tt></dt>
-<dd>This attribute indicates that the code generator should not use a
-red zone, even if the target-specific ABI normally permits it.
-</dd>
-
-<dt><tt>noimplicitfloat</tt></dt>
-<dd>This attributes disables implicit floating point instructions.</dd>
-
+ <dt><tt><b>alwaysinline</b></tt></dt>
+ <dd>This attribute indicates that the inliner should attempt to inline this
+ function into callers whenever possible, ignoring any active inlining size
+ threshold for this caller.</dd>
+
+ <dt><tt><b>inlinehint</b></tt></dt>
+ <dd>This attribute indicates that the source code contained a hint that inlining
+ this function is desirable (such as the "inline" keyword in C/C++). It
+ is just a hint; it imposes no requirements on the inliner.</dd>
+
+ <dt><tt><b>noinline</b></tt></dt>
+ <dd>This attribute indicates that the inliner should never inline this
+ function in any situation. This attribute may not be used together with
+ the <tt>alwaysinline</tt> attribute.</dd>
+
+ <dt><tt><b>optsize</b></tt></dt>
+ <dd>This attribute suggests that optimization passes and code generator passes
+ make choices that keep the code size of this function low, and otherwise
+ do optimizations specifically to reduce code size.</dd>
+
+ <dt><tt><b>noreturn</b></tt></dt>
+ <dd>This function attribute indicates that the function never returns
+ normally. This produces undefined behavior at runtime if the function
+ ever does dynamically return.</dd>
+
+ <dt><tt><b>nounwind</b></tt></dt>
+ <dd>This function attribute indicates that the function never returns with an
+ unwind or exceptional control flow. If the function does unwind, its
+ runtime behavior is undefined.</dd>
+
+ <dt><tt><b>readnone</b></tt></dt>
+ <dd>This attribute indicates that the function computes its result (or decides
+ to unwind an exception) based strictly on its arguments, without
+ dereferencing any pointer arguments or otherwise accessing any mutable
+ state (e.g. memory, control registers, etc) visible to caller functions.
+ It does not write through any pointer arguments
+ (including <tt><a href="#byval">byval</a></tt> arguments) and never
+ changes any state visible to callers. This means that it cannot unwind
+ exceptions by calling the <tt>C++</tt> exception throwing methods, but
+ could use the <tt>unwind</tt> instruction.</dd>
+
+ <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
+ <dd>This attribute indicates that the function does not write through any
+ pointer arguments (including <tt><a href="#byval">byval</a></tt>
+ arguments) or otherwise modify any state (e.g. memory, control registers,
+ etc) visible to caller functions. It may dereference pointer arguments
+ and read state that may be set in the caller. A readonly function always
+ returns the same value (or unwinds an exception identically) when called
+ with the same set of arguments and global state. It cannot unwind an
+ exception by calling the <tt>C++</tt> exception throwing methods, but may
+ use the <tt>unwind</tt> instruction.</dd>
+
+ <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
+ <dd>This attribute indicates that the function should emit a stack smashing
+ protector. It is in the form of a "canary"—a random value placed on
+ the stack before the local variables that's checked upon return from the
+ function to see if it has been overwritten. A heuristic is used to
+ determine if a function needs stack protectors or not.<br>
+<br>
+ If a function that has an <tt>ssp</tt> attribute is inlined into a
+ function that doesn't have an <tt>ssp</tt> attribute, then the resulting
+ function will have an <tt>ssp</tt> attribute.</dd>
+
+ <dt><tt><b>sspreq</b></tt></dt>
+ <dd>This attribute indicates that the function should <em>always</em> emit a
+ stack smashing protector. This overrides
+ the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
+<br>
+ If a function that has an <tt>sspreq</tt> attribute is inlined into a
+ function that doesn't have an <tt>sspreq</tt> attribute or which has
+ an <tt>ssp</tt> attribute, then the resulting function will have
+ an <tt>sspreq</tt> attribute.</dd>
+
+ <dt><tt><b>noredzone</b></tt></dt>
+ <dd>This attribute indicates that the code generator should not use a red
+ zone, even if the target-specific ABI normally permits it.</dd>
+
+ <dt><tt><b>noimplicitfloat</b></tt></dt>
+ <dd>This attributes disables implicit floating point instructions.</dd>
+
+ <dt><tt><b>naked</b></tt></dt>
+ <dd>This attribute disables prologue / epilogue emission for the function.
+ This can have very system-specific consequences.</dd>
</dl>
</div>
</div>
<div class="doc_text">
-<p>
-Modules may contain "module-level inline asm" blocks, which corresponds to the
-GCC "file scope inline asm" blocks. These blocks are internally concatenated by
-LLVM and treated as a single unit, but may be separated in the .ll file if
-desired. The syntax is very simple:
-</p>
+
+<p>Modules may contain "module-level inline asm" blocks, which corresponds to
+ the GCC "file scope inline asm" blocks. These blocks are internally
+ concatenated by LLVM and treated as a single unit, but may be separated in
+ the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
<div class="doc_code">
<pre>
<p>The strings can contain any character by escaping non-printable characters.
The escape sequence used is simply "\xx" where "xx" is the two digit hex code
- for the number.
-</p>
+ for the number.</p>
+
+<p>The inline asm code is simply printed to the machine code .s file when
+ assembly code is generated.</p>
-<p>
- The inline asm code is simply printed to the machine code .s file when
- assembly code is generated.
-</p>
</div>
<!-- ======================================================================= -->
</div>
<div class="doc_text">
+
<p>A module may specify a target specific data layout string that specifies how
-data is to be laid out in memory. The syntax for the data layout is simply:</p>
-<pre> target datalayout = "<i>layout specification</i>"</pre>
-<p>The <i>layout specification</i> consists of a list of specifications
-separated by the minus sign character ('-'). Each specification starts with a
-letter and may include other information after the letter to define some
-aspect of the data layout. The specifications accepted are as follows: </p>
+ data is to be laid out in memory. The syntax for the data layout is
+ simply:</p>
+
+<div class="doc_code">
+<pre>
+target datalayout = "<i>layout specification</i>"
+</pre>
+</div>
+
+<p>The <i>layout specification</i> consists of a list of specifications
+ separated by the minus sign character ('-'). Each specification starts with
+ a letter and may include other information after the letter to define some
+ aspect of the data layout. The specifications accepted are as follows:</p>
+
<dl>
<dt><tt>E</tt></dt>
<dd>Specifies that the target lays out data in big-endian form. That is, the
- bits with the most significance have the lowest address location.</dd>
+ bits with the most significance have the lowest address location.</dd>
+
<dt><tt>e</tt></dt>
<dd>Specifies that the target lays out data in little-endian form. That is,
- the bits with the least significance have the lowest address location.</dd>
+ the bits with the least significance have the lowest address
+ location.</dd>
+
<dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
- <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
- <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
- alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
- too.</dd>
+ <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
+ <i>preferred</i> alignments. All sizes are in bits. Specifying
+ the <i>pref</i> alignment is optional. If omitted, the
+ preceding <tt>:</tt> should be omitted too.</dd>
+
<dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
<dd>This specifies the alignment for an integer type of a given bit
- <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
+ <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
+
<dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
- <dd>This specifies the alignment for a vector type of a given bit
- <i>size</i>.</dd>
+ <dd>This specifies the alignment for a vector type of a given bit
+ <i>size</i>.</dd>
+
<dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
- <dd>This specifies the alignment for a floating point type of a given bit
- <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
- (double).</dd>
+ <dd>This specifies the alignment for a floating point type of a given bit
+ <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
+ (double).</dd>
+
<dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
<dd>This specifies the alignment for an aggregate type of a given bit
- <i>size</i>.</dd>
+ <i>size</i>.</dd>
+
<dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
<dd>This specifies the alignment for a stack object of a given bit
- <i>size</i>.</dd>
+ <i>size</i>.</dd>
+
+ <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
+ <dd>This specifies a set of native integer widths for the target CPU
+ in bits. For example, it might contain "n32" for 32-bit PowerPC,
+ "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
+ this set are considered to support most general arithmetic
+ operations efficiently.</dd>
</dl>
+
<p>When constructing the data layout for a given target, LLVM starts with a
-default set of specifications which are then (possibly) overriden by the
-specifications in the <tt>datalayout</tt> keyword. The default specifications
-are given in this list:</p>
+ default set of specifications which are then (possibly) overriden by the
+ specifications in the <tt>datalayout</tt> keyword. The default specifications
+ are given in this list:</p>
+
<ul>
<li><tt>E</tt> - big endian</li>
<li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
<li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
<li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
</ul>
-<p>When LLVM is determining the alignment for a given type, it uses the
-following rules:</p>
+
+<p>When LLVM is determining the alignment for a given type, it uses the
+ following rules:</p>
+
<ol>
<li>If the type sought is an exact match for one of the specifications, that
- specification is used.</li>
+ specification is used.</li>
+
<li>If no match is found, and the type sought is an integer type, then the
- smallest integer type that is larger than the bitwidth of the sought type is
- used. If none of the specifications are larger than the bitwidth then the the
- largest integer type is used. For example, given the default specifications
- above, the i7 type will use the alignment of i8 (next largest) while both
- i65 and i256 will use the alignment of i64 (largest specified).</li>
+ smallest integer type that is larger than the bitwidth of the sought type
+ is used. If none of the specifications are larger than the bitwidth then
+ the the largest integer type is used. For example, given the default
+ specifications above, the i7 type will use the alignment of i8 (next
+ largest) while both i65 and i256 will use the alignment of i64 (largest
+ specified).</li>
+
<li>If no match is found, and the type sought is a vector type, then the
- largest vector type that is smaller than the sought vector type will be used
- as a fall back. This happens because <128 x double> can be implemented
- in terms of 64 <2 x double>, for example.</li>
+ largest vector type that is smaller than the sought vector type will be
+ used as a fall back. This happens because <128 x double> can be
+ implemented in terms of 64 <2 x double>, for example.</li>
</ol>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="pointeraliasing">Pointer Aliasing Rules</a>
+</div>
+
+<div class="doc_text">
+
+<p>Any memory access must be done through a pointer value associated
+with an address range of the memory access, otherwise the behavior
+is undefined. Pointer values are associated with address ranges
+according to the following rules:</p>
+
+<ul>
+ <li>A pointer value formed from a
+ <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
+ is associated with the addresses associated with the first operand
+ of the <tt>getelementptr</tt>.</li>
+ <li>An address of a global variable is associated with the address
+ range of the variable's storage.</li>
+ <li>The result value of an allocation instruction is associated with
+ the address range of the allocated storage.</li>
+ <li>A null pointer in the default address-space is associated with
+ no address.</li>
+ <li>A pointer value formed by an
+ <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
+ address ranges of all pointer values that contribute (directly or
+ indirectly) to the computation of the pointer's value.</li>
+ <li>The result value of a
+ <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
+ addresses associated with the operand of the <tt>bitcast</tt>.</li>
+ <li>An integer constant other than zero or a pointer value returned
+ from a function not defined within LLVM may be associated with address
+ ranges allocated through mechanisms other than those provided by
+ LLVM. Such ranges shall not overlap with any ranges of addresses
+ allocated by mechanisms provided by LLVM.</li>
+ </ul>
+
+<p>LLVM IR does not associate types with memory. The result type of a
+<tt><a href="#i_load">load</a></tt> merely indicates the size and
+alignment of the memory from which to load, as well as the
+interpretation of the value. The first operand of a
+<tt><a href="#i_store">store</a></tt> similarly only indicates the size
+and alignment of the store.</p>
+
+<p>Consequently, type-based alias analysis, aka TBAA, aka
+<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
+LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
+additional information which specialized optimization passes may use
+to implement type-based alias analysis.</p>
+
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>The LLVM type system is one of the most important features of the
-intermediate representation. Being typed enables a number of
-optimizations to be performed on the intermediate representation directly,
-without having to do
-extra analyses on the side before the transformation. A strong type
-system makes it easier to read the generated code and enables novel
-analyses and transformations that are not feasible to perform on normal
-three address code representations.</p>
+ intermediate representation. Being typed enables a number of optimizations
+ to be performed on the intermediate representation directly, without having
+ to do extra analyses on the side before the transformation. A strong type
+ system makes it easier to read the generated code and enables novel analyses
+ and transformations that are not feasible to perform on normal three address
+ code representations.</p>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection"> <a name="t_classifications">Type
Classifications</a> </div>
+
<div class="doc_text">
-<p>The types fall into a few useful
-classifications:</p>
+
+<p>The types fall into a few useful classifications:</p>
<table border="1" cellspacing="0" cellpadding="4">
<tbody>
</tbody>
</table>
-<p>The <a href="#t_firstclass">first class</a> types are perhaps the
-most important. Values of these types are the only ones which can be
-produced by instructions, passed as arguments, or used as operands to
-instructions.</p>
+<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
+ important. Values of these types are the only ones which can be produced by
+ instructions.</p>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
<div class="doc_text">
+
<p>The primitive types are the fundamental building blocks of the LLVM
-system.</p>
+ system.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
+
+<div class="doc_text">
+
+<h5>Overview:</h5>
+<p>The integer type is a very simple type that simply specifies an arbitrary
+ bit width for the integer type desired. Any bit width from 1 bit to
+ 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
+
+<h5>Syntax:</h5>
+<pre>
+ iN
+</pre>
+
+<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
+ value.</p>
+
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left"><tt>i1</tt></td>
+ <td class="left">a single-bit integer.</td>
+ </tr>
+ <tr class="layout">
+ <td class="left"><tt>i32</tt></td>
+ <td class="left">a 32-bit integer.</td>
+ </tr>
+ <tr class="layout">
+ <td class="left"><tt>i1942652</tt></td>
+ <td class="left">a really big integer of over 1 million bits.</td>
+ </tr>
+</table>
</div>
<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
<div class="doc_text">
- <table>
- <tbody>
- <tr><th>Type</th><th>Description</th></tr>
- <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
- <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
- <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
- <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
- <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
- </tbody>
- </table>
+
+<table>
+ <tbody>
+ <tr><th>Type</th><th>Description</th></tr>
+ <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
+ <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
+ <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
+ <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
+ <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
+ </tbody>
+</table>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
<div class="doc_text">
+
<h5>Overview:</h5>
<p>The void type does not represent any value and has no size.</p>
<h5>Syntax:</h5>
-
<pre>
void
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
<div class="doc_text">
+
<h5>Overview:</h5>
<p>The label type represents code labels.</p>
<h5>Syntax:</h5>
-
<pre>
label
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
<div class="doc_text">
+
<h5>Overview:</h5>
-<p>The metadata type represents embedded metadata. The only derived type that
-may contain metadata is <tt>metadata*</tt> or a function type that returns or
-takes metadata typed parameters, but not pointer to metadata types.</p>
+<p>The metadata type represents embedded metadata. No derived types may be
+ created from metadata except for <a href="#t_function">function</a>
+ arguments.
<h5>Syntax:</h5>
-
<pre>
metadata
</pre>
+
</div>
<div class="doc_text">
-<p>The real power in LLVM comes from the derived types in the system.
-This is what allows a programmer to represent arrays, functions,
-pointers, and other useful types. Note that these derived types may be
-recursive: For example, it is possible to have a two dimensional array.</p>
-
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
-
-<div class="doc_text">
-
-<h5>Overview:</h5>
-<p>The integer type is a very simple derived type that simply specifies an
-arbitrary bit width for the integer type desired. Any bit width from 1 bit to
-2^23-1 (about 8 million) can be specified.</p>
-
-<h5>Syntax:</h5>
-
-<pre>
- iN
-</pre>
-
-<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
-value.</p>
-
-<h5>Examples:</h5>
-<table class="layout">
- <tr class="layout">
- <td class="left"><tt>i1</tt></td>
- <td class="left">a single-bit integer.</td>
- </tr>
- <tr class="layout">
- <td class="left"><tt>i32</tt></td>
- <td class="left">a 32-bit integer.</td>
- </tr>
- <tr class="layout">
- <td class="left"><tt>i1942652</tt></td>
- <td class="left">a really big integer of over 1 million bits.</td>
- </tr>
-</table>
-
-<p>Note that the code generator does not yet support large integer types
-to be used as function return types. The specific limit on how large a
-return type the code generator can currently handle is target-dependent;
-currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
-targets.</p>
+<p>The real power in LLVM comes from the derived types in the system. This is
+ what allows a programmer to represent arrays, functions, pointers, and other
+ useful types. Each of these types contain one or more element types which
+ may be a primitive type, or another derived type. For example, it is
+ possible to have a two dimensional array, using an array as the element type
+ of another array.</p>
</div>
<div class="doc_text">
<h5>Overview:</h5>
-
<p>The array type is a very simple derived type that arranges elements
-sequentially in memory. The array type requires a size (number of
-elements) and an underlying data type.</p>
+ sequentially in memory. The array type requires a size (number of elements)
+ and an underlying data type.</p>
<h5>Syntax:</h5>
-
<pre>
[<# elements> x <elementtype>]
</pre>
-<p>The number of elements is a constant integer value; elementtype may
-be any type with a size.</p>
+<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
+ be any type with a size.</p>
<h5>Examples:</h5>
<table class="layout">
</tr>
</table>
-<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
-length array. Normally, accesses past the end of an array are undefined in
-LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
-As a special case, however, zero length arrays are recognized to be variable
-length. This allows implementation of 'pascal style arrays' with the LLVM
-type "{ i32, [0 x float]}", for example.</p>
-
-<p>Note that the code generator does not yet support large aggregate types
-to be used as function return types. The specific limit on how large an
-aggregate return type the code generator can currently handle is
-target-dependent, and also dependent on the aggregate element types.</p>
+<p>There is no restriction on indexing beyond the end of the array implied by
+ a static type (though there are restrictions on indexing beyond the bounds
+ of an allocated object in some cases). This means that single-dimension
+ 'variable sized array' addressing can be implemented in LLVM with a zero
+ length array type. An implementation of 'pascal style arrays' in LLVM could
+ use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
+
<div class="doc_text">
<h5>Overview:</h5>
-
-<p>The function type can be thought of as a function signature. It
-consists of a return type and a list of formal parameter types. The
-return type of a function type is a scalar type, a void type, or a struct type.
-If the return type is a struct type then all struct elements must be of first
-class types, and the struct must have at least one element.</p>
+<p>The function type can be thought of as a function signature. It consists of
+ a return type and a list of formal parameter types. The return type of a
+ function type is a scalar type, a void type, or a struct type. If the return
+ type is a struct type then all struct elements must be of first class types,
+ and the struct must have at least one element.</p>
<h5>Syntax:</h5>
-
<pre>
- <returntype list> (<parameter list>)
+ <returntype> (<parameter list>)
</pre>
<p>...where '<tt><parameter list></tt>' is a comma-separated list of type
-specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
-which indicates that the function takes a variable number of arguments.
-Variable argument functions can access their arguments with the <a
- href="#int_varargs">variable argument handling intrinsic</a> functions.
-'<tt><returntype list></tt>' is a comma-separated list of
-<a href="#t_firstclass">first class</a> type specifiers.</p>
+ specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
+ which indicates that the function takes a variable number of arguments.
+ Variable argument functions can access their arguments with
+ the <a href="#int_varargs">variable argument handling intrinsic</a>
+ functions. '<tt><returntype></tt>' is a any type except
+ <a href="#t_label">label</a>.</p>
<h5>Examples:</h5>
<table class="layout">
</tr><tr class="layout">
<td class="left"><tt>float (i16 signext, i32 *) *
</tt></td>
- <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
- an <tt>i16</tt> that should be sign extended and a
- <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
+ <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
+ an <tt>i16</tt> that should be sign extended and a
+ <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
<tt>float</tt>.
</td>
</tr><tr class="layout">
<td class="left"><tt>i32 (i8*, ...)</tt></td>
- <td class="left">A vararg function that takes at least one
- <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
- which returns an integer. This is the signature for <tt>printf</tt> in
+ <td class="left">A vararg function that takes at least one
+ <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
+ which returns an integer. This is the signature for <tt>printf</tt> in
LLVM.
</td>
</tr><tr class="layout">
<td class="left"><tt>{i32, i32} (i32)</tt></td>
- <td class="left">A function taking an <tt>i32</tt>, returning two
- <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
+ <td class="left">A function taking an <tt>i32</tt>, returning a
+ <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
</td>
</tr>
</table>
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
+
<div class="doc_text">
+
<h5>Overview:</h5>
-<p>The structure type is used to represent a collection of data members
-together in memory. The packing of the field types is defined to match
-the ABI of the underlying processor. The elements of a structure may
-be any type that has a size.</p>
-<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
-and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
-field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
-instruction.</p>
+<p>The structure type is used to represent a collection of data members together
+ in memory. The packing of the field types is defined to match the ABI of the
+ underlying processor. The elements of a structure may be any type that has a
+ size.</p>
+
+<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
+ and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
+ with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
+ Structures in registers are accessed using the
+ '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
+ '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
<h5>Syntax:</h5>
-<pre> { <type list> }<br></pre>
+<pre>
+ { <type list> }
+</pre>
+
<h5>Examples:</h5>
<table class="layout">
<tr class="layout">
</tr>
</table>
-<p>Note that the code generator does not yet support large aggregate types
-to be used as function return types. The specific limit on how large an
-aggregate return type the code generator can currently handle is
-target-dependent, and also dependent on the aggregate element types.</p>
-
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
</div>
+
<div class="doc_text">
+
<h5>Overview:</h5>
<p>The packed structure type is used to represent a collection of data members
-together in memory. There is no padding between fields. Further, the alignment
-of a packed structure is 1 byte. The elements of a packed structure may
-be any type that has a size.</p>
-<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
-and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
-field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
-instruction.</p>
+ together in memory. There is no padding between fields. Further, the
+ alignment of a packed structure is 1 byte. The elements of a packed
+ structure may be any type that has a size.</p>
+
+<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
+ '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
+ the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
+
<h5>Syntax:</h5>
-<pre> < { <type list> } > <br></pre>
+<pre>
+ < { <type list> } >
+</pre>
+
<h5>Examples:</h5>
<table class="layout">
<tr class="layout">
an <tt>i32</tt>.</td>
</tr>
</table>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
+
<div class="doc_text">
+
<h5>Overview:</h5>
-<p>As in many languages, the pointer type represents a pointer or
-reference to another object, which must live in memory. Pointer types may have
-an optional address space attribute defining the target-specific numbered
-address space where the pointed-to object resides. The default address space is
-zero.</p>
+<p>As in many languages, the pointer type represents a pointer or reference to
+ another object, which must live in memory. Pointer types may have an optional
+ address space attribute defining the target-specific numbered address space
+ where the pointed-to object resides. The default address space is zero.</p>
-<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does
-it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
+<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
+ permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
<h5>Syntax:</h5>
-<pre> <type> *<br></pre>
+<pre>
+ <type> *
+</pre>
+
<h5>Examples:</h5>
<table class="layout">
<tr class="layout">
that resides in address space #5.</td>
</tr>
</table>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
+
<div class="doc_text">
<h5>Overview:</h5>
-
-<p>A vector type is a simple derived type that represents a vector
-of elements. Vector types are used when multiple primitive data
-are operated in parallel using a single instruction (SIMD).
-A vector type requires a size (number of
-elements) and an underlying primitive data type. Vectors must have a power
-of two length (1, 2, 4, 8, 16 ...). Vector types are
-considered <a href="#t_firstclass">first class</a>.</p>
+<p>A vector type is a simple derived type that represents a vector of elements.
+ Vector types are used when multiple primitive data are operated in parallel
+ using a single instruction (SIMD). A vector type requires a size (number of
+ elements) and an underlying primitive data type. Vector types are considered
+ <a href="#t_firstclass">first class</a>.</p>
<h5>Syntax:</h5>
-
<pre>
< <# elements> x <elementtype> >
</pre>
-<p>The number of elements is a constant integer value; elementtype may
-be any integer or floating point type.</p>
+<p>The number of elements is a constant integer value; elementtype may be any
+ integer or floating point type.</p>
<h5>Examples:</h5>
-
<table class="layout">
<tr class="layout">
<td class="left"><tt><4 x i32></tt></td>
</tr>
</table>
-<p>Note that the code generator does not yet support large vector types
-to be used as function return types. The specific limit on how large a
-vector return type codegen can currently handle is target-dependent;
-currently it's often a few times longer than a hardware vector register.</p>
-
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Overview:</h5>
-
<p>Opaque types are used to represent unknown types in the system. This
-corresponds (for example) to the C notion of a forward declared structure type.
-In LLVM, opaque types can eventually be resolved to any type (not just a
-structure type).</p>
+ corresponds (for example) to the C notion of a forward declared structure
+ type. In LLVM, opaque types can eventually be resolved to any type (not just
+ a structure type).</p>
<h5>Syntax:</h5>
-
<pre>
opaque
</pre>
<h5>Examples:</h5>
-
<table class="layout">
<tr class="layout">
<td class="left"><tt>opaque</tt></td>
<td class="left">An opaque type.</td>
</tr>
</table>
+
</div>
<!-- ======================================================================= -->
</div>
<div class="doc_text">
+
<h5>Overview:</h5>
-<p>
-An "up reference" allows you to refer to a lexically enclosing type without
-requiring it to have a name. For instance, a structure declaration may contain a
-pointer to any of the types it is lexically a member of. Example of up
-references (with their equivalent as named type declarations) include:</p>
+<p>An "up reference" allows you to refer to a lexically enclosing type without
+ requiring it to have a name. For instance, a structure declaration may
+ contain a pointer to any of the types it is lexically a member of. Example
+ of up references (with their equivalent as named type declarations)
+ include:</p>
<pre>
{ \2 * } %x = type { %x* }
\1* %z = type %z*
</pre>
-<p>
-An up reference is needed by the asmprinter for printing out cyclic types when
-there is no declared name for a type in the cycle. Because the asmprinter does
-not want to print out an infinite type string, it needs a syntax to handle
-recursive types that have no names (all names are optional in llvm IR).
-</p>
+<p>An up reference is needed by the asmprinter for printing out cyclic types
+ when there is no declared name for a type in the cycle. Because the
+ asmprinter does not want to print out an infinite type string, it needs a
+ syntax to handle recursive types that have no names (all names are optional
+ in llvm IR).</p>
<h5>Syntax:</h5>
<pre>
\<level>
</pre>
-<p>
-The level is the count of the lexical type that is being referred to.
-</p>
+<p>The level is the count of the lexical type that is being referred to.</p>
<h5>Examples:</h5>
-
<table class="layout">
<tr class="layout">
<td class="left"><tt>\1*</tt></td>
structure.</td>
</tr>
</table>
-</div>
+</div>
<!-- *********************************************************************** -->
<div class="doc_section"> <a name="constants">Constants</a> </div>
<div class="doc_text">
<p>LLVM has several different basic types of constants. This section describes
-them all and their syntax.</p>
+ them all and their syntax.</p>
</div>
<dl>
<dt><b>Boolean constants</b></dt>
-
<dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
- constants of the <tt><a href="#t_primitive">i1</a></tt> type.
- </dd>
+ constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
<dt><b>Integer constants</b></dt>
-
- <dd>Standard integers (such as '4') are constants of the <a
- href="#t_integer">integer</a> type. Negative numbers may be used with
- integer types.
- </dd>
+ <dd>Standard integers (such as '4') are constants of
+ the <a href="#t_integer">integer</a> type. Negative numbers may be used
+ with integer types.</dd>
<dt><b>Floating point constants</b></dt>
-
<dd>Floating point constants use standard decimal notation (e.g. 123.421),
- exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
- notation (see below). The assembler requires the exact decimal value of
- a floating-point constant. For example, the assembler accepts 1.25 but
- rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
- constants must have a <a href="#t_floating">floating point</a> type. </dd>
+ exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
+ notation (see below). The assembler requires the exact decimal value of a
+ floating-point constant. For example, the assembler accepts 1.25 but
+ rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
+
constants must have a <a href="#t_floating">floating point</a> type. </dd>
<dt><b>Null pointer constants</b></dt>
-
<dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
- and must be of <a href="#t_pointer">pointer type</a>.</dd>
-
+ and must be of <a href="#t_pointer">pointer type</a>.</dd>
</dl>
-<p>The one non-intuitive notation for constants is the hexadecimal form
-of floating point constants. For example, the form '<tt>double
-0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
-4.5e+15</tt>'. The only time hexadecimal floating point constants are required
-(and the only time that they are generated by the disassembler) is when a
-floating point constant must be emitted but it cannot be represented as a
-decimal floating point number in a reasonable number of digits. For example,
-NaN's, infinities, and other
-special values are represented in their IEEE hexadecimal format so that
-assembly and disassembly do not cause any bits to change in the constants.</p>
+<p>The one non-intuitive notation for constants is the hexadecimal form of
+ floating point constants. For example, the form '<tt>double
+ 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
+ '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
+ constants are required (and the only time that they are generated by the
+ disassembler) is when a floating point constant must be emitted but it cannot
+ be represented as a decimal floating point number in a reasonable number of
+ digits. For example, NaN's, infinities, and other special values are
+ represented in their IEEE hexadecimal format so that assembly and disassembly
+ do not cause any bits to change in the constants.</p>
+
<p>When using the hexadecimal form, constants of types float and double are
-represented using the 16-digit form shown above (which matches the IEEE754
-representation for double); float values must, however, be exactly representable
-as IEE754 single precision.
-Hexadecimal format is always used for long
-double, and there are three forms of long double. The 80-bit
-format used by x86 is represented as <tt>0xK</tt>
-followed by 20 hexadecimal digits.
-The 128-bit format used by PowerPC (two adjacent doubles) is represented
-by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
-format is represented
-by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
-target uses this format. Long doubles will only work if they match
-the long double format on your target. All hexadecimal formats are big-endian
-(sign bit at the left).</p>
+ represented using the 16-digit form shown above (which matches the IEEE754
+ representation for double); float values must, however, be exactly
+ representable as IEE754 single precision. Hexadecimal format is always used
+ for long double, and there are three forms of long double. The 80-bit format
+ used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
+ The 128-bit format used by PowerPC (two adjacent doubles) is represented
+ by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
+ is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
+ currently supported target uses this format. Long doubles will only work if
+ they match the long double format on your target. All hexadecimal formats
+ are big-endian (sign bit at the left).</p>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
-<a name="aggregateconstants"> <!-- old anchor -->
-<a name="complexconstants">Complex Constants</a></a>
+<a name="aggregateconstants"></a> <!-- old anchor -->
+<a name="complexconstants">Complex Constants</a>
</div>
<div class="doc_text">
+
<p>Complex constants are a (potentially recursive) combination of simple
-constants and smaller complex constants.</p>
+ constants and smaller complex constants.</p>
<dl>
<dt><b>Structure constants</b></dt>
-
<dd>Structure constants are represented with notation similar to structure
- type definitions (a comma separated list of elements, surrounded by braces
- (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
- where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
- must have <a href="#t_struct">structure type</a>, and the number and
- types of elements must match those specified by the type.
- </dd>
+ type definitions (a comma separated list of elements, surrounded by braces
+ (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
+ where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
+ Structure constants must have <a href="#t_struct">structure type</a>, and
+ the number and types of elements must match those specified by the
+ type.</dd>
<dt><b>Array constants</b></dt>
-
<dd>Array constants are represented with notation similar to array type
- definitions (a comma separated list of elements, surrounded by square brackets
- (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
- constants must have <a href="#t_array">array type</a>, and the number and
- types of elements must match those specified by the type.
- </dd>
+ definitions (a comma separated list of elements, surrounded by square
+ brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
+ ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
+ the number and types of elements must match those specified by the
+ type.</dd>
<dt><b>Vector constants</b></dt>
-
<dd>Vector constants are represented with notation similar to vector type
- definitions (a comma separated list of elements, surrounded by
- less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32 42,
- i32 11, i32 74, i32 100 ></tt>". Vector constants must have <a
- href="#t_vector">vector type</a>, and the number and types of elements must
- match those specified by the type.
- </dd>
+ definitions (a comma separated list of elements, surrounded by
+ less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32
+ 42, i32 11, i32 74, i32 100 ></tt>". Vector constants must
+ have <a href="#t_vector">vector type</a>, and the number and types of
+ elements must match those specified by the type.</dd>
<dt><b>Zero initialization</b></dt>
-
<dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
- value to zero of <em>any</em> type, including scalar and aggregate types.
- This is often used to avoid having to print large zero initializers (e.g. for
- large arrays) and is always exactly equivalent to using explicit zero
- initializers.
- </dd>
+ value to zero of <em>any</em> type, including scalar and aggregate types.
+ This is often used to avoid having to print large zero initializers
+ (e.g. for large arrays) and is always exactly equivalent to using explicit
+ zero initializers.</dd>
<dt><b>Metadata node</b></dt>
-
<dd>A metadata node is a structure-like constant with
- <a href="#t_metadata">metadata type</a>. For example:
- "<tt>metadata !{ i32 0, metadata !"test" }</tt>". Unlike other constants
- that are meant to be interpreted as part of the instruction stream, metadata
- is a place to attach additional information such as debug info.
- </dd>
+ <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
+ i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
+ be interpreted as part of the instruction stream, metadata is a place to
+ attach additional information such as debug info.</dd>
</dl>
</div>
<div class="doc_text">
-<p>The addresses of <a href="#globalvars">global variables</a> and <a
-href="#functionstructure">functions</a> are always implicitly valid (link-time)
-constants. These constants are explicitly referenced when the <a
-href="#identifiers">identifier for the global</a> is used and always have <a
-href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
-file:</p>
+<p>The addresses of <a href="#globalvars">global variables</a>
+ and <a href="#functionstructure">functions</a> are always implicitly valid
+ (link-time) constants. These constants are explicitly referenced when
+ the <a href="#identifiers">identifier for the global</a> is used and always
+ have <a href="#t_pointer">pointer</a> type. For example, the following is a
+ legal LLVM file:</p>
<div class="doc_code">
<pre>
<!-- ======================================================================= -->
<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
<div class="doc_text">
- <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
- no specific value. Undefined values may be of any type and be used anywhere
- a constant is permitted.</p>
- <p>Undefined values indicate to the compiler that the program is well defined
- no matter what value is used, giving the compiler more freedom to optimize.
- </p>
+<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
+ indicates that the user of the value may receive an unspecified bit-pattern.
+ Undefined values may be of any type (other than label or void) and be used
+ anywhere a constant is permitted.</p>
+
+<p>Undefined values are useful because they indicate to the compiler that the
+ program is well defined no matter what value is used. This gives the
+ compiler more freedom to optimize. Here are some examples of (potentially
+ surprising) transformations that are valid (in pseudo IR):</p>
+
+
+<div class="doc_code">
+<pre>
+ %A = add %X, undef
+ %B = sub %X, undef
+ %C = xor %X, undef
+Safe:
+ %A = undef
+ %B = undef
+ %C = undef
+</pre>
+</div>
+
+<p>This is safe because all of the output bits are affected by the undef bits.
+Any output bit can have a zero or one depending on the input bits.</p>
+
+<div class="doc_code">
+<pre>
+ %A = or %X, undef
+ %B = and %X, undef
+Safe:
+ %A = -1
+ %B = 0
+Unsafe:
+ %A = undef
+ %B = undef
+</pre>
+</div>
+
+<p>These logical operations have bits that are not always affected by the input.
+For example, if "%X" has a zero bit, then the output of the 'and' operation will
+always be a zero, no matter what the corresponding bit from the undef is. As
+such, it is unsafe to optimize or assume that the result of the and is undef.
+However, it is safe to assume that all bits of the undef could be 0, and
+optimize the and to 0. Likewise, it is safe to assume that all the bits of
+the undef operand to the or could be set, allowing the or to be folded to
+-1.</p>
+
+<div class="doc_code">
+<pre>
+ %A = select undef, %X, %Y
+ %B = select undef, 42, %Y
+ %C = select %X, %Y, undef
+Safe:
+ %A = %X (or %Y)
+ %B = 42 (or %Y)
+ %C = %Y
+Unsafe:
+ %A = undef
+ %B = undef
+ %C = undef
+</pre>
+</div>
+
+<p>This set of examples show that undefined select (and conditional branch)
+conditions can go "either way" but they have to come from one of the two
+operands. In the %A example, if %X and %Y were both known to have a clear low
+bit, then %A would have to have a cleared low bit. However, in the %C example,
+the optimizer is allowed to assume that the undef operand could be the same as
+%Y, allowing the whole select to be eliminated.</p>
+
+
+<div class="doc_code">
+<pre>
+ %A = xor undef, undef
+
+ %B = undef
+ %C = xor %B, %B
+
+ %D = undef
+ %E = icmp lt %D, 4
+ %F = icmp gte %D, 4
+
+Safe:
+ %A = undef
+ %B = undef
+ %C = undef
+ %D = undef
+ %E = undef
+ %F = undef
+</pre>
+</div>
+
+<p>This example points out that two undef operands are not necessarily the same.
+This can be surprising to people (and also matches C semantics) where they
+assume that "X^X" is always zero, even if X is undef. This isn't true for a
+number of reasons, but the short answer is that an undef "variable" can
+arbitrarily change its value over its "live range". This is true because the
+"variable" doesn't actually <em>have a live range</em>. Instead, the value is
+logically read from arbitrary registers that happen to be around when needed,
+so the value is not necessarily consistent over time. In fact, %A and %C need
+to have the same semantics or the core LLVM "replace all uses with" concept
+would not hold.</p>
+
+<div class="doc_code">
+<pre>
+ %A = fdiv undef, %X
+ %B = fdiv %X, undef
+Safe:
+ %A = undef
+b: unreachable
+</pre>
+</div>
+
+<p>These examples show the crucial difference between an <em>undefined
+value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
+allowed to have an arbitrary bit-pattern. This means that the %A operation
+can be constant folded to undef because the undef could be an SNaN, and fdiv is
+not (currently) defined on SNaN's. However, in the second example, we can make
+a more aggressive assumption: because the undef is allowed to be an arbitrary
+value, we are allowed to assume that it could be zero. Since a divide by zero
+has <em>undefined behavior</em>, we are allowed to assume that the operation
+does not execute at all. This allows us to delete the divide and all code after
+it: since the undefined operation "can't happen", the optimizer can assume that
+it occurs in dead code.
+</p>
+
+<div class="doc_code">
+<pre>
+a: store undef -> %X
+b: store %X -> undef
+Safe:
+a: <deleted>
+b: unreachable
+</pre>
+</div>
+
+<p>These examples reiterate the fdiv example: a store "of" an undefined value
+can be assumed to not have any effect: we can assume that the value is
+overwritten with bits that happen to match what was already there. However, a
+store "to" an undefined location could clobber arbitrary memory, therefore, it
+has undefined behavior.</p>
+
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
+ Blocks</a></div>
+<div class="doc_text">
+
+<p><b><tt>blockaddress(@function, %block)</tt></b></p>
+
+<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
+ basic block in the specified function, and always has an i8* type. Taking
+ the address of the entry block is illegal.</p>
+
+<p>This value only has defined behavior when used as an operand to the
+ '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
+ against null. Pointer equality tests between labels addresses is undefined
+ behavior - though, again, comparison against null is ok, and no label is
+ equal to the null pointer. This may also be passed around as an opaque
+ pointer sized value as long as the bits are not inspected. This allows
+ <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
+ the original value is reconstituted before the <tt>indirectbr</tt>.</p>
+
+<p>Finally, some targets may provide defined semantics when
+ using the value as the operand to an inline assembly, but that is target
+ specific.
+ </p>
+
+</div>
+
+
<!-- ======================================================================= -->
<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
</div>
<div class="doc_text">
<p>Constant expressions are used to allow expressions involving other constants
-to be used as constants. Constant expressions may be of any <a
-href="#t_firstclass">first class</a> type and may involve any LLVM operation
-that does not have side effects (e.g. load and call are not supported). The
-following is the syntax for constant expressions:</p>
+ to be used as constants. Constant expressions may be of
+ any <a href="#t_firstclass">first class</a> type and may involve any LLVM
+ operation that does not have side effects (e.g. load and call are not
+ supported). The following is the syntax for constant expressions:</p>
<dl>
<dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
- <dd>Truncate a constant to another type. The bit size of CST must be larger
- than the bit size of TYPE. Both types must be integers.</dd>
+ <dd>Truncate a constant to another type. The bit size of CST must be larger
+ than the bit size of TYPE. Both types must be integers.</dd>
<dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
- <dd>Zero extend a constant to another type. The bit size of CST must be
- smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
+ <dd>Zero extend a constant to another type. The bit size of CST must be
+ smaller or equal to the bit size of TYPE. Both types must be
+ integers.</dd>
<dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
- <dd>Sign extend a constant to another type. The bit size of CST must be
- smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
+ <dd>Sign extend a constant to another type. The bit size of CST must be
+ smaller or equal to the bit size of TYPE. Both types must be
+ integers.</dd>
<dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
- <dd>Truncate a floating point constant to another floating point type. The
- size of CST must be larger than the size of TYPE. Both types must be
- floating point.</dd>
+ <dd>Truncate a floating point constant to another floating point type. The
+ size of CST must be larger than the size of TYPE. Both types must be
+ floating point.</dd>
<dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
- <dd>Floating point extend a constant to another type. The size of CST must be
- smaller or equal to the size of TYPE. Both types must be floating point.</dd>
+ <dd>Floating point extend a constant to another type. The size of CST must be
+ smaller or equal to the size of TYPE. Both types must be floating
+ point.</dd>
<dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
<dd>Convert a floating point constant to the corresponding unsigned integer
- constant. TYPE must be a scalar or vector integer type. CST must be of scalar
- or vector floating point type. Both CST and TYPE must be scalars, or vectors
- of the same number of elements. If the value won't fit in the integer type,
- the results are undefined.</dd>
+ constant. TYPE must be a scalar or vector integer type. CST must be of
+ scalar or vector floating point type. Both CST and TYPE must be scalars,
+ or vectors of the same number of elements. If the value won't fit in the
+ integer type, the results are undefined.</dd>
<dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
<dd>Convert a floating point constant to the corresponding signed integer
- constant. TYPE must be a scalar or vector integer type. CST must be of scalar
- or vector floating point type. Both CST and TYPE must be scalars, or vectors
- of the same number of elements. If the value won't fit in the integer type,
- the results are undefined.</dd>
+ constant. TYPE must be a scalar or vector integer type. CST must be of
+ scalar or vector floating point type. Both CST and TYPE must be scalars,
+ or vectors of the same number of elements. If the value won't fit in the
+ integer type, the results are undefined.</dd>
<dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
<dd>Convert an unsigned integer constant to the corresponding floating point
- constant. TYPE must be a scalar or vector floating point type. CST must be of
- scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
- of the same number of elements. If the value won't fit in the floating point
- type, the results are undefined.</dd>
+ constant. TYPE must be a scalar or vector floating point type. CST must be
+ of scalar or vector integer type. Both CST and TYPE must be scalars, or
+ vectors of the same number of elements. If the value won't fit in the
+ floating point type, the results are undefined.</dd>
<dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
<dd>Convert a signed integer constant to the corresponding floating point
- constant. TYPE must be a scalar or vector floating point type. CST must be of
- scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
- of the same number of elements. If the value won't fit in the floating point
- type, the results are undefined.</dd>
+ constant. TYPE must be a scalar or vector floating point type. CST must be
+ of scalar or vector integer type. Both CST and TYPE must be scalars, or
+ vectors of the same number of elements. If the value won't fit in the
+ floating point type, the results are undefined.</dd>
<dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
<dd>Convert a pointer typed constant to the corresponding integer constant
- TYPE must be an integer type. CST must be of pointer type. The CST value is
- zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
+ <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
+ type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
+ make it fit in <tt>TYPE</tt>.</dd>
<dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
- <dd>Convert a integer constant to a pointer constant. TYPE must be a
- pointer type. CST must be of integer type. The CST value is zero extended,
- truncated, or unchanged to make it fit in a pointer size. This one is
- <i>really</i> dangerous!</dd>
+ <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
+ type. CST must be of integer type. The CST value is zero extended,
+ truncated, or unchanged to make it fit in a pointer size. This one is
+ <i>really</i> dangerous!</dd>
<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
<dd>Convert a constant, CST, to another TYPE. The constraints of the operands
instruction</a>.</dd>
<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
-
+ <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
<dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
- constants. As with the <a href="#i_getelementptr">getelementptr</a>
- instruction, the index list may have zero or more indexes, which are required
- to make sense for the type of "CSTPTR".</dd>
+
constants. As with the <a href="#i_getelementptr">getelementptr</a>
+ instruction, the index list may have zero or more indexes, which are
+ required to make sense for the type of "CSTPTR".</dd>
<dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
-
- <dd>Perform the <a href="#i_select">select operation</a> on
- constants.</dd>
+ <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
<dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
<dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
<dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
<dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
- <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
- <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
+ <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
+ <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
+ constants.</dd>
- <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
- <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
+ <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
+ <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
+ constants.</dd>
- <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
+ <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
+ <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
+ constants.</dd>
- <dd>Perform the <a href="#i_extractelement">extractelement
- operation</a> on constants.</dd>
+ <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
+ <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
+ be any of the <a href="#binaryops">binary</a>
+ or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
+ on operands are the same as those for the corresponding instruction
+ (e.g. no bitwise operations on floating point values are allowed).</dd>
+</dl>
- <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
+</div>
- <dd>Perform the <a href="#i_insertelement">insertelement
- operation</a> on constants.</dd>
+<!-- *********************************************************************** -->
+<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
+<!-- *********************************************************************** -->
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+<a name="inlineasm">Inline Assembler Expressions</a>
+</div>
- <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
+<div class="doc_text">
- <dd>Perform the <a href="#i_shufflevector">shufflevector
- operation</a> on constants.</dd>
+<p>LLVM supports inline assembler expressions (as opposed
+ to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
+ a special value. This value represents the inline assembler as a string
+ (containing the instructions to emit), a list of operand constraints (stored
+ as a string), a flag that indicates whether or not the inline asm
+ expression has side effects, and a flag indicating whether the function
+ containing the asm needs to align its stack conservatively. An example
+ inline assembler expression is:</p>
- <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
+<div class="doc_code">
+<pre>
+i32 (i32) asm "bswap $0", "=r,r"
+</pre>
+</div>
+
+<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
+ a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
+ have:</p>
+
+<div class="doc_code">
+<pre>
+%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
+</pre>
+</div>
+
+<p>Inline asms with side effects not visible in the constraint list must be
+ marked as having side effects. This is done through the use of the
+ '<tt>sideeffect</tt>' keyword, like so:</p>
+
+<div class="doc_code">
+<pre>
+call void asm sideeffect "eieio", ""()
+</pre>
+</div>
+
+<p>In some cases inline asms will contain code that will not work unless the
+ stack is aligned in some way, such as calls or SSE instructions on x86,
+ yet will not contain code that does that alignment within the asm.
+ The compiler should make conservative assumptions about what the asm might
+ contain and should generate its usual stack alignment code in the prologue
+ if the '<tt>alignstack</tt>' keyword is present:</p>
+
+<div class="doc_code">
+<pre>
+call void asm alignstack "eieio", ""()
+</pre>
+</div>
+
+<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
+ first.</p>
+
+<p>TODO: The format of the asm and constraints string still need to be
+ documented here. Constraints on what can be done (e.g. duplication, moving,
+ etc need to be documented). This is probably best done by reference to
+ another document that covers inline asm from a holistic perspective.</p>
- <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
- be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
- binary</a> operations. The constraints on operands are the same as those for
- the corresponding instruction (e.g. no bitwise operations on floating point
- values are allowed).</dd>
-</dl>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
+<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
+ Strings</a>
</div>
<div class="doc_text">
-<p>Embedded metadata provides a way to attach arbitrary data to the
-instruction stream without affecting the behaviour of the program. There are
-two metadata primitives, strings and nodes. All metadata has the
-<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
-point ('<tt>!</tt>').
-</p>
+<p>LLVM IR allows metadata to be attached to instructions in the program that
+ can convey extra information about the code to the optimizers and code
+ generator. One example application of metadata is source-level debug
+ information. There are two metadata primitives: strings and nodes. All
+ metadata has the <tt>metadata</tt> type and is identified in syntax by a
+ preceding exclamation point ('<tt>!</tt>').</p>
<p>A metadata string is a string surrounded by double quotes. It can contain
-any character by escaping non-printable characters with "\xx" where "xx" is
-the two digit hex code. For example: "<tt>!"test\00"</tt>".
-</p>
+ any character by escaping non-printable characters with "\xx" where "xx" is
+ the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
<p>Metadata nodes are represented with notation similar to structure constants
-(a comma separated list of elements, surrounded by braces and preceeded by an
-exclamation point). For example: "<tt>!{ metadata !"test\00", i32 10}</tt>".
-</p>
+ (a comma separated list of elements, surrounded by braces and preceded by an
+ exclamation point). For example: "<tt>!{ metadata !"test\00", i32
+ 10}</tt>". Metadata nodes can have any values as their operand.</p>
-<p>A metadata node will attempt to track changes to the values it holds. In
-the event that a value is deleted, it will be replaced with a typeless
-"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
+<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
+ metadata nodes, which can be looked up in the module symbol table. For
+ example: "<tt>!foo = metadata !{!4, !3}</tt>".
-<p>Optimizations may rely on metadata to provide additional information about
-the program that isn't available in the instructions, or that isn't easily
-computable. Similarly, the code generator may expect a certain metadata format
-to be used to express debugging information.</p>
</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
+<div class="doc_section">
+ <a name="intrinsic_globals">Intrinsic Global Variables</a>
+</div>
<!-- *********************************************************************** -->
+<p>LLVM has a number of "magic" global variables that contain data that affect
+code generation or other IR semantics. These are documented here. All globals
+of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
+section and all globals that start with "<tt>llvm.</tt>" are reserved for use
+by LLVM.</p>
+
<!-- ======================================================================= -->
<div class="doc_subsection">
-<a name="inlineasm">Inline Assembler Expressions</a>
+<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
</div>
<div class="doc_text">
-<p>
-LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
-Module-Level Inline Assembly</a>) through the use of a special value. This
-value represents the inline assembler as a string (containing the instructions
-to emit), a list of operand constraints (stored as a string), and a flag that
-indicates whether or not the inline asm expression has side effects. An example
-inline assembler expression is:
-</p>
+<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
+href="#linkage_appending">appending linkage</a>. This array contains a list of
+pointers to global variables and functions which may optionally have a pointer
+cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
-<div class="doc_code">
<pre>
-i32 (i32) asm "bswap $0", "=r,r"
+ @X = global i8 4
+ @Y = global i32 123
+
+ @llvm.used = appending global [2 x i8*] [
+ i8* @X,
+ i8* bitcast (i32* @Y to i8*)
+ ], section "llvm.metadata"
</pre>
+
+<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
+compiler, assembler, and linker are required to treat the symbol as if there is
+a reference to the global that it cannot see. For example, if a variable has
+internal linkage and no references other than that from the <tt>@llvm.used</tt>
+list, it cannot be deleted. This is commonly used to represent references from
+inline asms and other things the compiler cannot "see", and corresponds to
+"attribute((used))" in GNU C.</p>
+
+<p>On some targets, the code generator must emit a directive to the assembler or
+object file to prevent the assembler and linker from molesting the symbol.</p>
+
</div>
-<p>
-Inline assembler expressions may <b>only</b> be used as the callee operand of
-a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
-</p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
+</div>
+
+<div class="doc_text">
+
+<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
+<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
+touching the symbol. On targets that support it, this allows an intelligent
+linker to optimize references to the symbol without being impeded as it would be
+by <tt>@llvm.used</tt>.</p>
+
+<p>This is a rare construct that should only be used in rare circumstances, and
+should not be exposed to source languages.</p>
-<div class="doc_code">
-<pre>
-%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
-</pre>
</div>
-<p>
-Inline asms with side effects not visible in the constraint list must be marked
-as having side effects. This is done through the use of the
-'<tt>sideeffect</tt>' keyword, like so:
-</p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
+</div>
+
+<div class="doc_text">
+
+<p>TODO: Describe this.</p>
-<div class="doc_code">
-<pre>
-call void asm sideeffect "eieio", ""()
-</pre>
</div>
-<p>TODO: The format of the asm and constraints string still need to be
-documented here. Constraints on what can be done (e.g. duplication, moving, etc
-need to be documented). This is probably best done by reference to another
-document that covers inline asm from a holistic perspective.
-</p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
+</div>
+
+<div class="doc_text">
+
+<p>TODO: Describe this.</p>
</div>
+
<!-- *********************************************************************** -->
<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
<!-- *********************************************************************** -->
<div class="doc_text">
-<p>The LLVM instruction set consists of several different
-
classifications of instructions: <a href="#terminators">terminator
-instructions</a>, <a href="#binaryops">binary instructions</a>,
-<a href="#bitwiseops">bitwise binary instructions</a>, <a
- href="#memoryops">memory instructions</a>, and <a href="#otherops">other
-instructions</a>.</p>
+<p>The LLVM instruction set consists of several different classifications of
+
instructions: <a href="#terminators">terminator
+
instructions</a>, <a href="#binaryops">binary instructions</a>,
+ <a href="#bitwiseops">bitwise binary instructions</a>,
+ <a href="#memoryops">memory instructions</a>, and
+ <a href="#otherops">other instructions</a>.</p>
</div>
<div class="doc_text">
-<p>As mentioned <a href="#functionstructure">previously</a>, every
-basic block in a program ends with a "Terminator" instruction, which
-indicates which block should be executed after the current block is
-finished. These terminator instructions typically yield a '<tt>void</tt>'
-value: they produce control flow, not values (the one exception being
-the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
-<p>There are six different terminator instructions: the '<a
- href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
-instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
-the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
- href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
- href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
+<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
+ in a program ends with a "Terminator" instruction, which indicates which
+ block should be executed after the current block is finished. These
+ terminator instructions typically yield a '<tt>void</tt>' value: they produce
+ control flow, not values (the one exception being the
+ '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
+
+<p>There are six different terminator instructions: the
+ '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
+ '<a href="#i_br"><tt>br</tt></a>' instruction, the
+ '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
+ '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
+ '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
+ '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
+ '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
<pre>
ret <type> <value> <i>; Return a value from a non-void function</i>
</pre>
<h5>Overview:</h5>
+<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
+ a value) from a function back to the caller.</p>
-<p>The '<tt>ret</tt>' instruction is used to return control flow (and
-optionally a value) from a function back to the caller.</p>
-<p>There are two forms of the '<tt>ret</tt>' instruction: one that
-returns a value and then causes control flow, and one that just causes
-control flow to occur.</p>
+<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
+ value and then causes control flow, and one that just causes control flow to
+ occur.</p>
<h5>Arguments:</h5>
+<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
+ return value. The type of the return value must be a
+ '<a href="#t_firstclass">first class</a>' type.</p>
-<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
-the return value. The type of the return value must be a
-'<a href="#t_firstclass">first class</a>' type.</p>
-
-<p>A function is not <a href="#wellformed">well formed</a> if
-it it has a non-void return type and contains a '<tt>ret</tt>'
-instruction with no return value or a return value with a type that
-does not match its type, or if it has a void return type and contains
-a '<tt>ret</tt>' instruction with a return value.</p>
+<p>A function is not <a href="#wellformed">well formed</a> if it it has a
+ non-void return type and contains a '<tt>ret</tt>' instruction with no return
+ value or a return value with a type that does not match its type, or if it
+ has a void return type and contains a '<tt>ret</tt>' instruction with a
+ return value.</p>
<h5>Semantics:</h5>
-
-<p>When the '<tt>ret</tt>' instruction is executed, control flow
-returns back to the calling function's context. If the caller is a "<a
- href="#i_call"><tt>call</tt></a>" instruction, execution continues at
-the instruction after the call. If the caller was an "<a
- href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
-at the beginning of the "normal" destination block. If the instruction
-returns a value, that value shall set the call or invoke instruction's
-return value.</p>
+<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
+ the calling function's context. If the caller is a
+ "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
+ instruction after the call. If the caller was an
+ "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
+ the beginning of the "normal" destination block. If the instruction returns
+ a value, that value shall set the call or invoke instruction's return
+ value.</p>
<h5>Example:</h5>
-
<pre>
ret i32 5 <i>; Return an integer value of 5</i>
ret void <i>; Return from a void function</i>
ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
</pre>
-<p>Note that the code generator does not yet fully support large
- return values. The specific sizes that are currently supported are
- dependent on the target. For integers, on 32-bit targets the limit
- is often 64 bits, and on 64-bit targets the limit is often 128 bits.
- For aggregate types, the current limits are dependent on the element
- types; for example targets are often limited to 2 total integer
- elements and 2 total floating-point elements.</p>
-
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
+<pre>
+ br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>br</tt>' instruction is used to cause control flow to
-transfer to a different basic block in the current function. There are
-two forms of this instruction, corresponding to a conditional branch
-and an unconditional branch.</p>
+<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
+ different basic block in the current function. There are two forms of this
+ instruction, corresponding to a conditional branch and an unconditional
+ branch.</p>
+
<h5>Arguments:</h5>
-<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
-single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
-unconditional form of the '<tt>br</tt>' instruction takes a single
-'<tt>label</tt>' value as a target.</p>
+<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
+ '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
+ of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
+ target.</p>
+
<h5>Semantics:</h5>
<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
-argument is evaluated. If the value is <tt>true</tt>, control flows
-to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
-control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
+ argument is evaluated. If the value is <tt>true</tt>, control flows to the
+ '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
+ control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
+
<h5>Example:</h5>
-<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
- href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
+<pre>
+Test:
+ %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
+ br i1 %cond, label %IfEqual, label %IfUnequal
+IfEqual:
+ <a href="#i_ret">ret</a> i32 1
+IfUnequal:
+ <a href="#i_ret">ret</a> i32 0
+</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_switch">'<tt>switch</tt>' Instruction</a>
</div>
<div class="doc_text">
-<h5>Syntax:</h5>
+<h5>Syntax:</h5>
<pre>
switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
-several different places. It is a generalization of the '<tt>br</tt>'
-instruction, allowing a branch to occur to one of many possible
-destinations.</p>
-
+ several different places. It is a generalization of the '<tt>br</tt>'
+ instruction, allowing a branch to occur to one of many possible
+ destinations.</p>
<h5>Arguments:</h5>
-
<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
-comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
-an array of pairs of comparison value constants and '<tt>label</tt>'s. The
-table is not allowed to contain duplicate constant entries.</p>
+ comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
+ and an array of pairs of comparison value constants and '<tt>label</tt>'s.
+ The table is not allowed to contain duplicate constant entries.</p>
<h5>Semantics:</h5>
-
<p>The <tt>switch</tt> instruction specifies a table of values and
-destinations. When the '<tt>switch</tt>' instruction is executed, this
-table is searched for the given value. If the value is found, control flow is
-transfered to the corresponding destination; otherwise, control flow is
-transfered to the default destination.</p>
+ destinations. When the '<tt>switch</tt>' instruction is executed, this table
+ is searched for the given value. If the value is found, control flow is
+ transferred to the corresponding destination; otherwise, control flow is
+ transferred to the default destination.</p>
<h5>Implementation:</h5>
-
<p>Depending on properties of the target machine and the particular
-<tt>switch</tt> instruction, this instruction may be code generated in different
-ways. For example, it could be generated as a series of chained conditional
-branches or with a lookup table.</p>
+ <tt>switch</tt> instruction, this instruction may be code generated in
+ different ways. For example, it could be generated as a series of chained
+ conditional branches or with a lookup table.</p>
<h5>Example:</h5>
-
<pre>
<i>; Emulate a conditional br instruction</i>
%Val = <a href="#i_zext">zext</a> i1 %value to i32
i32 1, label %onone
i32 2, label %ontwo ]
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
+ <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
+<pre>
+ indirectbr <somety>* <address>, [ label <dest1>, label <dest2>, ... ]
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
+ within the current function, whose address is specified by
+ "<tt>address</tt>". Address must be derived from a <a
+ href="#blockaddress">blockaddress</a> constant.</p>
+<h5>Arguments:</h5>
+
+<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
+ rest of the arguments indicate the full set of possible destinations that the
+ address may point to. Blocks are allowed to occur multiple times in the
+ destination list, though this isn't particularly useful.</p>
+
+<p>This destination list is required so that dataflow analysis has an accurate
+ understanding of the CFG.</p>
+
+<h5>Semantics:</h5>
+
+<p>Control transfers to the block specified in the address argument. All
+ possible destination blocks must be listed in the label list, otherwise this
+ instruction has undefined behavior. This implies that jumps to labels
+ defined in other functions have undefined behavior as well.</p>
+
+<h5>Implementation:</h5>
+
+<p>This is typically implemented with a jump through a register.</p>
+
+<h5>Example:</h5>
+<pre>
+ indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
+</pre>
+
+</div>
+
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
<pre>
<result> = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] <ptr to function ty> <function ptr val>(<function args>) [<a href="#fnattrs">fn attrs</a>]
to label <normal label> unwind label <exception label>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
-function, with the possibility of control flow transfer to either the
-'<tt>normal</tt>' label or the
-'<tt>exception</tt>' label. If the callee function returns with the
-"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
-"normal" label. If the callee (or any indirect callees) returns with the "<a
-href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
-continued at the dynamically nearest "exception" label.</p>
+ function, with the possibility of control flow transfer to either the
+ '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
+ function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
+ control flow will return to the "normal" label. If the callee (or any
+ indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
+ instruction, control is interrupted and continued at the dynamically nearest
+ "exception" label.</p>
<h5>Arguments:</h5>
-
<p>This instruction requires several arguments:</p>
<ol>
- <li>
- The optional "cconv" marker indicates which <a href="#callingconv">calling
- convention</a> the call should use. If none is specified, the call defaults
- to using C calling conventions.
- </li>
+ <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
+ convention</a> the call should use. If none is specified, the call
+ defaults to using C calling conventions.</li>
<li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
- return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
- and '<tt>inreg</tt>' attributes are valid here.</li>
+ return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
+ '<tt>inreg</tt>' attributes are valid here.</li>
<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
- function value being invoked. In most cases, this is a direct function
- invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
- an arbitrary pointer to function value.
- </li>
+ function value being invoked. In most cases, this is a direct function
+ invocation, but indirect <tt>invoke</tt>s are just as possible, branching
+ off an arbitrary pointer to function value.</li>
<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
- function to be invoked. </li>
+ function to be invoked. </li>
<li>'<tt>function args</tt>': argument list whose types match the function
- signature argument types. If the function signature indicates the function
- accepts a variable number of arguments, the extra arguments can be
- specified. </li>
+ signature argument types. If the function signature indicates the
+ function accepts a variable number of arguments, the extra arguments can
+ be specified.</li>
<li>'<tt>normal label</tt>': the label reached when the called function
- executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
+
executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
<li>'<tt>exception label</tt>': the label reached when a callee returns with
- the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
+
the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
<li>The optional <a href="#fnattrs">function attributes</a> list. Only
- '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
- '<tt>readnone</tt>' attributes are valid here.</li>
+ '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
+ '<tt>readnone</tt>' attributes are valid here.</li>
</ol>
<h5>Semantics:</h5>
-
-<p>This instruction is designed to operate as a standard '<tt><a
-href="#i_call">call</a></tt>' instruction in most regards. The primary
-difference is that it establishes an association with a label, which is used by
-the runtime library to unwind the stack.</p>
+<p>This instruction is designed to operate as a standard
+ '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
+ primary difference is that it establishes an association with a label, which
+ is used by the runtime library to unwind the stack.</p>
<p>This instruction is used in languages with destructors to ensure that proper
-cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
-exception. Additionally, this is important for implementation of
-'<tt>catch</tt>' clauses in high-level languages that support them.</p>
+ cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
+ exception. Additionally, this is important for implementation of
+ '<tt>catch</tt>' clauses in high-level languages that support them.</p>
-<p>For the purposes of the SSA form, the definition of the value
-returned by the '<tt>invoke</tt>' instruction is deemed to occur on
-the edge from the current block to the "normal" label. If the callee
-unwinds then no return value is available.</p>
+<p>For the purposes of the SSA form, the definition of the value returned by the
+ '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
+ block to the "normal" label. If the callee unwinds then no return value is
+ available.</p>
+
+<p>Note that the code generator does not yet completely support unwind, and
+that the invoke/unwind semantics are likely to change in future versions.</p>
<h5>Example:</h5>
<pre>
%retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
unwind label %TestCleanup <i>; {i32}:retval set</i>
</pre>
-</div>
+</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
-at the first callee in the dynamic call stack which used an <a
-href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
-primarily used to implement exception handling.</p>
+ at the first callee in the dynamic call stack which used
+ an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
+ This is primarily used to implement exception handling.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
-immediately halt. The dynamic call stack is then searched for the first <a
-href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
-execution continues at the "exceptional" destination block specified by the
-<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
-dynamic call chain, undefined behavior results.</p>
+ immediately halt. The dynamic call stack is then searched for the
+ first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
+ Once found, execution continues at the "exceptional" destination block
+ specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
+ instruction in the dynamic call chain, undefined behavior results.</p>
+
+<p>Note that the code generator does not yet completely support unwind, and
+that the invoke/unwind semantics are likely to change in future versions.</p>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
-instruction is used to inform the optimizer that a particular portion of the
-code is not reachable. This can be used to indicate that the code after a
-no-return function cannot be reached, and other facts.</p>
+ instruction is used to inform the optimizer that a particular portion of the
+ code is not reachable. This can be used to indicate that the code after a
+ no-return function cannot be reached, and other facts.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
-</div>
-
+</div>
<!-- ======================================================================= -->
<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
+
<div class="doc_text">
-<p>Binary operators are used to do most of the computation in a
-program. They require two operands of the same type, execute an operation on them, and
-produce a single value. The operands might represent
-multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
-The result value has the same type as its operands.</p>
+
+<p>Binary operators are used to do most of the computation in a program. They
+ require two operands of the same type, execute an operation on them, and
+ produce a single value. The operands might represent multiple data, as is
+ the case with the <a href="#t_vector">vector</a> data type. The result value
+ has the same type as its operands.</p>
+
<p>There are several different binary operators:</p>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_add">'<tt>add</tt>' Instruction</a>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
- <result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = add nuw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = add nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = add nuw nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>add</tt>' instruction must be <a
- href="#t_integer">integer</a> or
- <a href="#t_vector">vector</a> of integer values. Both arguments must
- have identical types.</p>
+<p>The two arguments to the '<tt>add</tt>' instruction must
+ be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
+ integer values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the integer sum of the two operands.</p>
-<p>If the sum has unsigned overflow, the result returned is the
-mathematical result modulo 2<sup>n</sup>, where n is the bit width of
-the result.</p>
+<p>If the sum has unsigned overflow, the result returned is the mathematical
+ result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
-<p>Because LLVM integers use a two's complement representation, this
-instruction is appropriate for both signed and unsigned integers.</p>
+<p>Because LLVM integers use a two's complement representation, this instruction
+ is appropriate for both signed and unsigned integers.</p>
-<h5>Example:</h5>
+<p><tt>nuw</tt> and <tt>nsw</tt> stand for "No Unsigned Wrap"
+ and "No Signed Wrap", respectively. If the <tt>nuw</tt> and/or
+ <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
+ is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
+<h5>Example:</h5>
<pre>
<result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = fadd <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
<h5>Arguments:</h5>
-
<p>The two arguments to the '<tt>fadd</tt>' instruction must be
-<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
-floating point values. Both arguments must have identical types.</p>
+
<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
+ floating point values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the floating point sum of the two operands.</p>
<h5>Example:</h5>
-
<pre>
<result> = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_sub">'<tt>sub</tt>' Instruction</a>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
- <result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = sub nuw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = sub nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = sub nuw nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>sub</tt>' instruction returns the difference of its two
-operands.</p>
+ operands.</p>
<p>Note that the '<tt>sub</tt>' instruction is used to represent the
-'<tt>neg</tt>' instruction present in most other intermediate
-representations.</p>
+ '<tt>neg</tt>' instruction present in most other intermediate
+ representations.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
- href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
- integer values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>sub</tt>' instruction must
+ be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
+ integer values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the integer difference of the two operands.</p>
<p>If the difference has unsigned overflow, the result returned is the
-mathematical result modulo 2<sup>n</sup>, where n is the bit width of
-the result.</p>
+ mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
+ result.</p>
+
+<p>Because LLVM integers use a two's complement representation, this instruction
+ is appropriate for both signed and unsigned integers.</p>
-<p>Because LLVM integers use a two's complement representation, this
-instruction is appropriate for both signed and unsigned integers.</p>
+<p><tt>nuw</tt> and <tt>nsw</tt> stand for "No Unsigned Wrap"
+ and "No Signed Wrap", respectively. If the <tt>nuw</tt> and/or
+ <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
+ is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
<h5>Example:</h5>
<pre>
<result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = fsub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>fsub</tt>' instruction returns the difference of its two
-operands.</p>
+ operands.</p>
<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
-'<tt>fneg</tt>' instruction present in most other intermediate
-representations.</p>
+ '<tt>fneg</tt>' instruction present in most other intermediate
+ representations.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>fsub</tt>' instruction must be <a
- <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
- of floating point values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>fsub</tt>' instruction must be
+ <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
+ floating point values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the floating point difference of the two operands.</p>
<h5>Example:</h5>
<result> = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
<result> = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> <result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = mul nuw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = mul nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = mul nuw nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>mul</tt>' instruction returns the product of its two
-operands.</p>
+<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>mul</tt>' instruction must
+ be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
+ integer values. Both arguments must have identical types.</p>
-<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
-href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
-
<h5>Semantics:</h5>
-
<p>The value produced is the integer product of the two operands.</p>
-<p>If the result of the multiplication has unsigned overflow,
-the result returned is the mathematical result modulo
-2<sup>n</sup>, where n is the bit width of the result.</p>
-<p>Because LLVM integers use a two's complement representation, and the
-result is the same width as the operands, this instruction returns the
-correct result for both signed and unsigned integers. If a full product
-(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
-should be sign-extended or zero-extended as appropriate to the
-width of the full product.</p>
+<p>If the result of the multiplication has unsigned overflow, the result
+ returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
+ width of the result.</p>
+
+<p>Because LLVM integers use a two's complement representation, and the result
+ is the same width as the operands, this instruction returns the correct
+ result for both signed and unsigned integers. If a full product
+ (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
+ be sign-extended or zero-extended as appropriate to the width of the full
+ product.</p>
+
+<p><tt>nuw</tt> and <tt>nsw</tt> stand for "No Unsigned Wrap"
+ and "No Signed Wrap", respectively. If the <tt>nuw</tt> and/or
+ <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
+ is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
+
<h5>Example:</h5>
-<pre> <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
+<pre>
+ <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> <result> = fmul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = fmul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>fmul</tt>' instruction returns the product of its two
-operands.</p>
+<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
<h5>Arguments:</h5>
-
<p>The two arguments to the '<tt>fmul</tt>' instruction must be
-<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
-of floating point values. Both arguments must have identical types.</p>
+ <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
+ floating point values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the floating point product of the two operands.</p>
<h5>Example:</h5>
-<pre> <result> = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
+<pre>
+ <result> = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
</a></div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
-operands.</p>
+<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>udiv</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>udiv</tt>' instruction must be
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the unsigned integer quotient of the two operands.</p>
+
<p>Note that unsigned integer division and signed integer division are distinct
-operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
+ operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
+
<p>Division by zero leads to undefined behavior.</p>
+
<h5>Example:</h5>
-<pre> <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
+<pre>
+ <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
<pre>
- <result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = sdiv exact <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
-<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
-operands.</p>
+<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
+<p>The value produced is the signed integer quotient of the two operands rounded
+ towards zero.</p>
+
<p>Note that signed integer division and unsigned integer division are distinct
-operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
+ operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
+
<p>Division by zero leads to undefined behavior. Overflow also leads to
-undefined behavior; this is a rare case, but can occur, for example,
-by doing a 32-bit division of -2147483648 by -1.</p>
+ undefined behavior; this is a rare case, but can occur, for example, by doing
+ a 32-bit division of -2147483648 by -1.</p>
+
+<p>If the <tt>exact</tt> keyword is present, the result value of the
+ <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
+ would occur.</p>
+
<h5>Example:</h5>
-<pre> <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
+<pre>
+ <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
<pre>
<result> = fdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
-<h5>Overview:</h5>
-<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
-operands.</p>
+<h5>Overview:</h5>
+<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
<h5>Arguments:</h5>
-
<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
-<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
-of floating point values. Both arguments must have identical types.</p>
+ <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
+ floating point values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The value produced is the floating point quotient of the two operands.</p>
<h5>Example:</h5>
-
<pre>
<result> = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>urem</tt>' instruction returns the remainder from the
-unsigned division of its two arguments.</p>
+<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
+ division of its two arguments.</p>
+
<h5>Arguments:</h5>
-<p>The two arguments to the '<tt>urem</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>urem</tt>' instruction must be
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
+
<h5>Semantics:</h5>
<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
-This instruction always performs an unsigned division to get the remainder.</p>
+ This instruction always performs an unsigned division to get the
+ remainder.</p>
+
<p>Note that unsigned integer remainder and signed integer remainder are
-distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
+ distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
+
<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
+
<h5>Example:</h5>
-<pre> <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
+<pre>
+ <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
</pre>
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_srem">'<tt>srem</tt>' Instruction</a>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = srem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
-<p>The '<tt>srem</tt>' instruction returns the remainder from the
-signed division of its two operands. This instruction can also take
-<a href="#t_vector">vector</a> versions of the values in which case
-the elements must be integers.</p>
+<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
+ division of its two operands. This instruction can also take
+ <a href="#t_vector">vector</a> versions of the values in which case the
+ elements must be integers.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>srem</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>srem</tt>' instruction must be
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>This instruction returns the <i>remainder</i> of a division (where the result
-has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
-operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
-a value. For more information about the difference, see <a
- href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
-Math Forum</a>. For a table of how this is implemented in various languages,
-please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
-Wikipedia: modulo operation</a>.</p>
+ has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
+ operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
+ a value. For more information about the difference,
+ see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
+ Math Forum</a>. For a table of how this is implemented in various languages,
+ please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
+ Wikipedia: modulo operation</a>.</p>
+
<p>Note that signed integer remainder and unsigned integer remainder are
-distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
+ distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
+
<p>Taking the remainder of a division by zero leads to undefined behavior.
-Overflow also leads to undefined behavior; this is a rare case, but can occur,
-for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
-(The remainder doesn't actually overflow, but this rule lets srem be
-implemented using instructions that return both the result of the division
-and the remainder.)</p>
+ Overflow also leads to undefined behavior; this is a rare case, but can
+ occur, for example, by taking the remainder of a 32-bit division of
+ -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
+ lets srem be implemented using instructions that return both the result of
+ the division and the remainder.)</p>
+
<h5>Example:</h5>
-<pre> <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
+<pre>
+ <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
</pre>
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> <result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>frem</tt>' instruction returns the remainder from the
-division of its two operands.</p>
+<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
+ its two operands.</p>
+
<h5>Arguments:</h5>
<p>The two arguments to the '<tt>frem</tt>' instruction must be
-<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
-of floating point values. Both arguments must have identical types.</p>
+ <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
+ floating point values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
-<p>This instruction returns the <i>remainder</i> of a division.
-The remainder has the same sign as the dividend.</p>
+<p>This instruction returns the <i>remainder</i> of a division. The remainder
+ has the same sign as the dividend.</p>
<h5>Example:</h5>
-
<pre>
<result> = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
</pre>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
Operations</a> </div>
+
<div class="doc_text">
-<p>Bitwise binary operators are used to do various forms of
-bit-twiddling in a program. They are generally very efficient
-instructions and can commonly be strength reduced from other
-instructions. They require two operands of the same type, execute an operation on them,
-and produce a single value. The resulting value is the same type as its operands.</p>
+
+<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
+ program. They are generally very efficient instructions and can commonly be
+ strength reduced from other instructions. They require two operands of the
+ same type, execute an operation on them, and produce a single value. The
+ resulting value is the same type as its operands.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
-<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
-the left a specified number of bits.</p>
+<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
+ a specified number of bits.</p>
<h5>Arguments:</h5>
+<p>Both arguments to the '<tt>shl</tt>' instruction must be the
+ same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
+ integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
-<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
- href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-type. '<tt>op2</tt>' is treated as an unsigned value.</p>
-
<h5>Semantics:</h5>
+<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
+ 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
+ is (statically or dynamically) negative or equal to or larger than the number
+ of bits in <tt>op1</tt>, the result is undefined. If the arguments are
+ vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
+ shift amount in <tt>op2</tt>.</p>
-<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
-where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
-equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
-If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
-corresponding shift amount in <tt>op2</tt>.</p>
-
-<h5>Example:</h5><pre>
+<h5>Example:</h5>
+<pre>
<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
<result> = shl i32 1, 32 <i>; undefined</i>
<result> = shl <2 x i32> < i32 1, i32 1>, < i32 1, i32 2> <i>; yields: result=<2 x i32> < i32 2, i32 4></i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
-operand shifted to the right a specified number of bits with zero fill.</p>
+<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
+ operand shifted to the right a specified number of bits with zero fill.</p>
<h5>Arguments:</h5>
-<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-type. '<tt>op2</tt>' is treated as an unsigned value.</p>
+<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ type. '<tt>op2</tt>' is treated as an unsigned value.</p>
<h5>Semantics:</h5>
-
<p>This instruction always performs a logical shift right operation. The most
-significant bits of the result will be filled with zero bits after the
-shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
-the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
-vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
-amount in <tt>op2</tt>.</p>
+ significant bits of the result will be filled with zero bits after the shift.
+ If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
+ number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
+ vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
+ shift amount in <tt>op2</tt>.</p>
<h5>Example:</h5>
<pre>
<result> = lshr i32 1, 32 <i>; undefined</i>
<result> = lshr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 2> <i>; yields: result=<2 x i32> < i32 0x7FFFFFFF, i32 1></i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
-operand shifted to the right a specified number of bits with sign extension.</p>
+<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
+ operand shifted to the right a specified number of bits with sign
+ extension.</p>
<h5>Arguments:</h5>
-<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-type. '<tt>op2</tt>' is treated as an unsigned value.</p>
+<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ type. '<tt>op2</tt>' is treated as an unsigned value.</p>
<h5>Semantics:</h5>
-<p>This instruction always performs an arithmetic shift right operation,
-The most significant bits of the result will be filled with the sign bit
-of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
-larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
-arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
-corresponding shift amount in <tt>op2</tt>.</p>
+<p>This instruction always performs an arithmetic shift right operation, The
+ most significant bits of the result will be filled with the sign bit
+ of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
+ larger than the number of bits in <tt>op1</tt>, the result is undefined. If
+ the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
+ the corresponding shift amount in <tt>op2</tt>.</p>
<h5>Example:</h5>
<pre>
<result> = ashr i32 1, 32 <i>; undefined</i>
<result> = ashr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 3> <i>; yields: result=<2 x i32> < i32 -1, i32 0></i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = and <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
-
-<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
-its two operands.</p>
+<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
+ operands.</p>
<h5>Arguments:</h5>
-
-<p>The two arguments to the '<tt>and</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>and</tt>' instruction must be
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
-<p> </p>
-<div>
+
<table border="1" cellspacing="0" cellpadding="4">
<tbody>
<tr>
</tr>
</tbody>
</table>
-</div>
+
<h5>Example:</h5>
<pre>
<result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
-or of its two operands.</p>
+<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
+ two operands.</p>
+
<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>or</tt>' instruction must be
+ <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
-<p>The two arguments to the '<tt>or</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
-<p> </p>
-<div>
+
<table border="1" cellspacing="0" cellpadding="4">
<tbody>
<tr>
</tr>
</tbody>
</table>
-</div>
+
<h5>Example:</h5>
-<pre> <result> = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
+<pre>
+ <result> = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
<result> = or i32 15, 40 <i>; yields {i32}:result = 47</i>
<result> = or i32 4, 8 <i>; yields {i32}:result = 12</i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+<pre>
+ <result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
-or of its two operands. The <tt>xor</tt> is used to implement the
-"one's complement" operation, which is the "~" operator in C.</p>
+<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
+ its two operands. The <tt>xor</tt> is used to implement the "one's
+ complement" operation, which is the "~" operator in C.</p>
+
<h5>Arguments:</h5>
-<p>The two arguments to the '<tt>xor</tt>' instruction must be
-<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
-values. Both arguments must have identical types.</p>
+<p>The two arguments to the '<tt>xor</tt>' instruction must be
+
<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
+ values. Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
-<p> </p>
-<div>
+
<table border="1" cellspacing="0" cellpadding="4">
<tbody>
<tr>
</tr>
</tbody>
</table>
-</div>
-<p> </p>
+
<h5>Example:</h5>
-<pre> <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
+<pre>
+ <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
<result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
<result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
<result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
</pre>
+
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<div class="doc_subsection">
<a name="vectorops">Vector Operations</a>
</div>
<div class="doc_text">
<p>LLVM supports several instructions to represent vector operations in a
-target-independent manner. These instructions cover the element-access and
-vector-specific operations needed to process vectors effectively. While LLVM
-does directly support these vector operations, many sophisticated algorithms
-will want to use target-specific intrinsics to take full advantage of a specific
-target.</p>
+ target-independent manner. These instructions cover the element-access and
+ vector-specific operations needed to process vectors effectively. While LLVM
+ does directly support these vector operations, many sophisticated algorithms
+ will want to use target-specific intrinsics to take full advantage of a
+ specific target.</p>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
-<pre>
- <result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
-</pre>
-
-<h5>Overview:</h5>
-
-<p>
-The '<tt>extractelement</tt>' instruction extracts a single scalar
-element from a vector at a specified index.
-</p>
-
-
-<h5>Arguments:</h5>
-
-<p>
-The first operand of an '<tt>extractelement</tt>' instruction is a
-value of <a href="#t_vector">vector</a> type. The second operand is
-an index indicating the position from which to extract the element.
-The index may be a variable.</p>
-
-<h5>Semantics:</h5>
-
-<p>
-The result is a scalar of the same type as the element type of
-<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
-<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
-results are undefined.
-</p>
-
-<h5>Example:</h5>
-
-<pre>
- %result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
-</pre>
-</div>
-
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
-</div>
-
-<div class="doc_text">
-
-<h5>Syntax:</h5>
-
-<pre>
- <result> = insertelement <n x <ty>> <val>, <ty> <elt>, i32 <idx> <i>; yields <n x <ty>></i>
-</pre>
-
-<h5>Overview:</h5>
-
-<p>
-The '<tt>insertelement</tt>' instruction inserts a scalar
-element into a vector at a specified index.
-</p>
-
-
-<h5>Arguments:</h5>
-
-<p>
-The first operand of an '<tt>insertelement</tt>' instruction is a
-value of <a href="#t_vector">vector</a> type. The second operand is a
-scalar value whose type must equal the element type of the first
-operand. The third operand is an index indicating the position at
-which to insert the value. The index may be a variable.</p>
-
-<h5>Semantics:</h5>
-
-<p>
-The result is a vector of the same type as <tt>val</tt>. Its
-element values are those of <tt>val</tt> except at position
-<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
-exceeds the length of <tt>val</tt>, the results are undefined.
-</p>
-
-<h5>Example:</h5>
-
-<pre>
- %result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
-</pre>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
-</div>
-
-<div class="doc_text">
-
-<h5>Syntax:</h5>
-
-<pre>
- <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <m x i32> <mask> <i>; yields <m x <ty>></i>
-</pre>
-
-<h5>Overview:</h5>
-
-<p>
-The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
-from two input vectors, returning a vector with the same element type as
-the input and length that is the same as the shuffle mask.
-</p>
-
-<h5>Arguments:</h5>
-
-<p>
-The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
-with types that match each other. The third argument is a shuffle mask whose
-element type is always 'i32'. The result of the instruction is a vector whose
-length is the same as the shuffle mask and whose element type is the same as
-the element type of the first two operands.
-</p>
-
-<p>
-The shuffle mask operand is required to be a constant vector with either
-constant integer or undef values.
-</p>
-
-<h5>Semantics:</h5>
-
-<p>
-The elements of the two input vectors are numbered from left to right across
-both of the vectors. The shuffle mask operand specifies, for each element of
-the result vector, which element of the two input vectors the result element
-gets. The element selector may be undef (meaning "don't care") and the second
-operand may be undef if performing a shuffle from only one vector.
-</p>
-
-<h5>Example:</h5>
-
-<pre>
- %result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
- <4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
- %result = shufflevector <4 x i32> %v1, <4 x i32> undef,
- <4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
- %result = shufflevector <8 x i32> %v1, <8 x i32> undef,
- <4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i>
- %result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
- <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 > <i>; yields <8 x i32></i>
+<pre>
+ <result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
</pre>
-</div>
+<h5>Overview:</h5>
+<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
+ from a vector at a specified index.</p>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="aggregateops">Aggregate Operations</a>
-</div>
-<div class="doc_text">
+<h5>Arguments:</h5>
+<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
+ of <a href="#t_vector">vector</a> type. The second operand is an index
+ indicating the position from which to extract the element. The index may be
+ a variable.</p>
-<p>LLVM supports several instructions for working with aggregate values.
-</p>
+<h5>Semantics:</h5>
+<p>The result is a scalar of the same type as the element type of
+ <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
+ <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
+ results are undefined.</p>
+
+<h5>Example:</h5>
+<pre>
+ <result> = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
+</pre>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
+ <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
- <result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
+ <result> = insertelement <n x <ty>> <val>, <ty> <elt>, i32 <idx> <i>; yields <n x <ty>></i>
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
-or array element from an aggregate value.
-</p>
-
+<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
+ vector at a specified index.</p>
<h5>Arguments:</h5>
-
-<p>
-The first operand of an '<tt>extractvalue</tt>' instruction is a
-value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
-type. The operands are constant indices to specify which value to extract
-in a similar manner as indices in a
-'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
-</p>
+<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
+ of <a href="#t_vector">vector</a> type. The second operand is a scalar value
+ whose type must equal the element type of the first operand. The third
+ operand is an index indicating the position at which to insert the value.
+ The index may be a variable.</p>
<h5>Semantics:</h5>
-
-<p>
-The result is the value at the position in the aggregate specified by
-the index operands.
-</p>
+<p>The result is a vector of the same type as <tt>val</tt>. Its element values
+ are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
+ value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
+ results are undefined.</p>
<h5>Example:</h5>
-
<pre>
- %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
+ <result> = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
</pre>
-</div>
+</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
+ <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
- <result> = insertvalue <aggregate type> <val>, <ty> <val>, <idx> <i>; yields <n x <ty>></i>
+ <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <m x i32> <mask> <i>; yields <m x <ty>></i>
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>insertvalue</tt>' instruction inserts a value
-into a struct field or array element in an aggregate.
-</p>
-
+<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
+ from two input vectors, returning a vector with the same element type as the
+ input and length that is the same as the shuffle mask.</p>
<h5>Arguments:</h5>
+<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
+ with types that match each other. The third argument is a shuffle mask whose
+ element type is always 'i32'. The result of the instruction is a vector
+ whose length is the same as the shuffle mask and whose element type is the
+ same as the element type of the first two operands.</p>
-<p>
-The first operand of an '<tt>insertvalue</tt>' instruction is a
-value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
-The second operand is a first-class value to insert.
-The following operands are constant indices
-indicating the position at which to insert the value in a similar manner as
-indices in a
-'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
-The value to insert must have the same type as the value identified
-by the indices.
-</p>
+<p>The shuffle mask operand is required to be a constant vector with either
+ constant integer or undef values.</p>
<h5>Semantics:</h5>
-
-<p>
-The result is an aggregate of the same type as <tt>val</tt>. Its
-value is that of <tt>val</tt> except that the value at the position
-specified by the indices is that of <tt>elt</tt>.
-</p>
+<p>The elements of the two input vectors are numbered from left to right across
+ both of the vectors. The shuffle mask operand specifies, for each element of
+ the result vector, which element of the two input vectors the result element
+ gets. The element selector may be undef (meaning "don't care") and the
+ second operand may be undef if performing a shuffle from only one vector.</p>
<h5>Example:</h5>
-
<pre>
- %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
+ <result> = shufflevector <4 x i32> %v1, <4 x i32> %v2,
+ <4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
+ <result> = shufflevector <4 x i32> %v1, <4 x i32> undef,
+ <4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
+ <result> = shufflevector <8 x i32> %v1, <8 x i32> undef,
+ <4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i>
+ <result> = shufflevector <4 x i32> %v1, <4 x i32> %v2,
+ <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 > <i>; yields <8 x i32></i>
</pre>
-</div>
+</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="memoryops">Memory Access and Addressing Operations</a>
+<div class="doc_subsection">
+ <a name="aggregateops">Aggregate Operations</a>
</div>
<div class="doc_text">
-<p>A key design point of an SSA-based representation is how it
-represents memory. In LLVM, no memory locations are in SSA form, which
-makes things very simple. This section describes how to read, write,
-allocate, and free memory in LLVM.</p>
+<p>LLVM supports several instructions for working with aggregate values.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
+ <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
- <result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
+ <result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
</pre>
<h5>Overview:</h5>
-
-<p>The '<tt>malloc</tt>' instruction allocates memory from the system
-heap and returns a pointer to it. The object is always allocated in the generic
-address space (address space zero).</p>
+<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
+ or array element from an aggregate value.</p>
<h5>Arguments:</h5>
-
-<p>The '<tt>malloc</tt>' instruction allocates
-<tt>sizeof(<type>)*NumElements</tt>
-bytes of memory from the operating system and returns a pointer of the
-appropriate type to the program. If "NumElements" is specified, it is the
-number of elements allocated, otherwise "NumElements" is defaulted to be one.
-If a constant alignment is specified, the value result of the allocation is
-guaranteed to be aligned to at least that boundary. If not specified, or if
-zero, the target can choose to align the allocation on any convenient boundary
-compatible with the type.</p>
-
-<p>'<tt>type</tt>' must be a sized type.</p>
+<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
+ of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
+ operands are constant indices to specify which value to extract in a similar
+ manner as indices in a
+ '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
<h5>Semantics:</h5>
-
-<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
-a pointer is returned. The result of a zero byte allocation is undefined. The
-result is null if there is insufficient memory available.</p>
+<p>The result is the value at the position in the aggregate specified by the
+ index operands.</p>
<h5>Example:</h5>
-
<pre>
- %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
-
- %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
- %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
- %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
- %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
- %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
+ <result> = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
</pre>
-<p>Note that the code generator does not yet respect the
- alignment value.</p>
-
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="i_free">'<tt>free</tt>' Instruction</a>
+ <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
- free <type> <value> <i>; yields {void}</i>
+ <result> = insertvalue <aggregate type> <val>, <ty> <elt>, <idx> <i>; yields <aggregate type></i>
</pre>
<h5>Overview:</h5>
+<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
+ array element in an aggregate.</p>
-<p>The '<tt>free</tt>' instruction returns memory back to the unused
-memory heap to be reallocated in the future.</p>
<h5>Arguments:</h5>
-
-<p>'<tt>value</tt>' shall be a pointer value that points to a value
-that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
-instruction.</p>
+<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
+ of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
+ second operand is a first-class value to insert. The following operands are
+ constant indices indicating the position at which to insert the value in a
+ similar manner as indices in a
+ '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
+ value to insert must have the same type as the value identified by the
+ indices.</p>
<h5>Semantics:</h5>
-
-<p>Access to the memory pointed to by the pointer is no longer defined
-after this instruction executes. If the pointer is null, the operation
-is a noop.</p>
+<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
+ that of <tt>val</tt> except that the value at the position specified by the
+ indices is that of <tt>elt</tt>.</p>
<h5>Example:</h5>
-
<pre>
- %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
- free [4 x i8]* %array
+ %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
+ %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
</pre>
+
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="memoryops">Memory Access and Addressing Operations</a>
+</div>
+
+<div class="doc_text">
+
+<p>A key design point of an SSA-based representation is how it represents
+ memory. In LLVM, no memory locations are in SSA form, which makes things
+ very simple. This section describes how to read, write, and allocate
+ memory in LLVM.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
-currently executing function, to be automatically released when this function
-returns to its caller. The object is always allocated in the generic address
-space (address space zero).</p>
+ currently executing function, to be automatically released when this function
+ returns to its caller. The object is always allocated in the generic address
+ space (address space zero).</p>
<h5>Arguments:</h5>
-
-<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
-bytes of memory on the runtime stack, returning a pointer of the
-appropriate type to the program. If "NumElements" is specified, it is the
-number of elements allocated, otherwise "NumElements" is defaulted to be one.
-If a constant alignment is specified, the value result of the allocation is
-guaranteed to be aligned to at least that boundary. If not specified, or if
-zero, the target can choose to align the allocation on any convenient boundary
-compatible with the type.</p>
+<p>The '<tt>alloca</tt>' instruction
+ allocates <tt>sizeof(<type>)*NumElements</tt> bytes of memory on the
+ runtime stack, returning a pointer of the appropriate type to the program.
+ If "NumElements" is specified, it is the number of elements allocated,
+ otherwise "NumElements" is defaulted to be one. If a constant alignment is
+ specified, the value result of the allocation is guaranteed to be aligned to
+ at least that boundary. If not specified, or if zero, the target can choose
+ to align the allocation on any convenient boundary compatible with the
+ type.</p>
<p>'<tt>type</tt>' may be any sized type.</p>
<h5>Semantics:</h5>
-
<p>Memory is allocated; a pointer is returned. The operation is undefined if
-there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
-memory is automatically released when the function returns. The '<tt>alloca</tt>'
-instruction is commonly used to represent automatic variables that must
-have an address available. When the function returns (either with the <tt><a
- href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
-instructions), the memory is reclaimed. Allocating zero bytes
-is legal, but the result is undefined.</p>
+ there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
+ memory is automatically released when the function returns. The
+ '<tt>alloca</tt>' instruction is commonly used to represent automatic
+ variables that must have an address available. When the function returns
+ (either with the <tt><a href="#i_ret">ret</a></tt>
+ or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
+ reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
<h5>Example:</h5>
-
<pre>
%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
%ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
%ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = load <ty>* <pointer>[, align <alignment>]<br> <result> = volatile load <ty>* <pointer>[, align <alignment>]<br></pre>
+<pre>
+ <result> = load <ty>* <pointer>[, align <alignment>]
+ <result> = volatile load <ty>* <pointer>[, align <alignment>]
+</pre>
+
<h5>Overview:</h5>
<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
+
<h5>Arguments:</h5>
-<p>The argument to the '<tt>load</tt>' instruction specifies the memory
-address from which to load. The pointer must point to a <a
- href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
-marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
-the number or order of execution of this <tt>load</tt> with other
-volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
-instructions. </p>
-<p>
-The optional constant "align" argument specifies the alignment of the operation
-(that is, the alignment of the memory address). A value of 0 or an
-omitted "align" argument means that the operation has the preferential
-alignment for the target. It is the responsibility of the code emitter
-to ensure that the alignment information is correct. Overestimating
-the alignment results in an undefined behavior. Underestimating the
-alignment may produce less efficient code. An alignment of 1 is always
-safe.
-</p>
+<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
+ from which to load. The pointer must point to
+ a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
+ marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
+ number or order of execution of this <tt>load</tt> with other
+ volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
+ instructions. </p>
+
+<p>The optional constant "align" argument specifies the alignment of the
+ operation (that is, the alignment of the memory address). A value of 0 or an
+ omitted "align" argument means that the operation has the preferential
+ alignment for the target. It is the responsibility of the code emitter to
+ ensure that the alignment information is correct. Overestimating the
+ alignment results in an undefined behavior. Underestimating the alignment may
+ produce less efficient code. An alignment of 1 is always safe.</p>
+
<h5>Semantics:</h5>
-<p>The location of memory pointed to is loaded. If the value being loaded
-is of scalar type then the number of bytes read does not exceed the minimum
-number of bytes needed to hold all bits of the type. For example, loading an
-<tt>i24</tt> reads at most three bytes. When loading a value of a type like
-<tt>i20</tt> with a size that is not an integral number of bytes, the result
-is undefined if the value was not originally written using a store of the
-same type.</p>
+<p>The location of memory pointed to is loaded. If the value being loaded is of
+ scalar type then the number of bytes read does not exceed the minimum number
+ of bytes needed to hold all bits of the type. For example, loading an
+ <tt>i24</tt> reads at most three bytes. When loading a value of a type like
+ <tt>i20</tt> with a size that is not an integral number of bytes, the result
+ is undefined if the value was not originally written using a store of the
+ same type.</p>
+
<h5>Examples:</h5>
-<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
- <a
- href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
+<pre>
+ %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
+ <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
%val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
</pre>
+
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
Instruction</a> </div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
+<pre>
+ store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
</pre>
+
<h5>Overview:</h5>
<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
+
<h5>Arguments:</h5>
-<p>There are two arguments to the '<tt>store</tt>' instruction: a value
-to store and an address at which to store it. The type of the '<tt><pointer></tt>'
-operand must be a pointer to the <a href="#t_firstclass">first class</a> type
-of the '<tt><value></tt>'
-operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
-optimizer is not allowed to modify the number or order of execution of
-this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
- href="#i_store">store</a></tt> instructions.</p>
-<p>
-The optional constant "align" argument specifies the alignment of the operation
-(that is, the alignment of the memory address). A value of 0 or an
-omitted "align" argument means that the operation has the preferential
-alignment for the target. It is the responsibility of the code emitter
-to ensure that the alignment information is correct. Overestimating
-the alignment results in an undefined behavior. Underestimating the
-alignment may produce less efficient code. An alignment of 1 is always
-safe.
-</p>
+<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
+ and an address at which to store it. The type of the
+ '<tt><pointer></tt>' operand must be a pointer to
+ the <a href="#t_firstclass">first class</a> type of the
+ '<tt><value></tt>' operand. If the <tt>store</tt> is marked
+ as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
+ or order of execution of this <tt>store</tt> with other
+ volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
+ instructions.</p>
+
+<p>The optional constant "align" argument specifies the alignment of the
+ operation (that is, the alignment of the memory address). A value of 0 or an
+ omitted "align" argument means that the operation has the preferential
+ alignment for the target. It is the responsibility of the code emitter to
+ ensure that the alignment information is correct. Overestimating the
+ alignment results in an undefined behavior. Underestimating the alignment may
+ produce less efficient code. An alignment of 1 is always safe.</p>
+
<h5>Semantics:</h5>
-<p>The contents of memory are updated to contain '<tt><value></tt>'
-at the location specified by the '<tt><pointer></tt>' operand.
-If '<tt><value></tt>' is of scalar type then the number of bytes
-written does not exceed the minimum number of bytes needed to hold all
-bits of the type. For example, storing an <tt>i24</tt> writes at most
-three bytes. When writing a value of a type like <tt>i20</tt> with a
-size that is not an integral number of bytes, it is unspecified what
-happens to the extra bits that do not belong to the type, but they will
-typically be overwritten.</p>
+<p>The contents of memory are updated to contain '<tt><value></tt>' at the
+ location specified by the '<tt><pointer></tt>' operand. If
+ '<tt><value></tt>' is of scalar type then the number of bytes written
+ does not exceed the minimum number of bytes needed to hold all bits of the
+ type. For example, storing an <tt>i24</tt> writes at most three bytes. When
+ writing a value of a type like <tt>i20</tt> with a size that is not an
+ integral number of bytes, it is unspecified what happens to the extra bits
+ that do not belong to the type, but they will typically be overwritten.</p>
+
<h5>Example:</h5>
-<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
+<pre>
+ %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
store i32 3, i32* %ptr <i>; yields {void}</i>
%val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</div>
<div class="doc_text">
+
<h5>Syntax:</h5>
<pre>
<result> = getelementptr <pty>* <ptrval>{, <ty> <idx>}*
+ <result> = getelementptr inbounds <pty>* <ptrval>{, <ty> <idx>}*
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>getelementptr</tt>' instruction is used to get the address of a
-subelement of an aggregate data structure. It performs address calculation only
-and does not access memory.</p>
+<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
+ subelement of an aggregate data structure. It performs address calculation
+ only and does not access memory.</p>
<h5>Arguments:</h5>
-
<p>The first argument is always a pointer, and forms the basis of the
-calculation. The remaining arguments are indices, that indicate which of the
-elements of the aggregate object are indexed. The interpretation of each index
-is dependent on the type being indexed into. The first index always indexes the
-pointer value given as the first argument, the second index indexes a value of
-the type pointed to (not necessarily the value directly pointed to, since the
-first index can be non-zero), etc. The first type indexed into must be a pointer
-value, subsequent types can be arrays, vectors and structs. Note that subsequent
-types being indexed into can never be pointers, since that would require loading
-the pointer before continuing calculation.</p>
+ calculation. The remaining arguments are indices that indicate which of the
+ elements of the aggregate object are indexed. The interpretation of each
+ index is dependent on the type being indexed into. The first index always
+ indexes the pointer value given as the first argument, the second index
+ indexes a value of the type pointed to (not necessarily the value directly
+ pointed to, since the first index can be non-zero), etc. The first type
+ indexed into must be a pointer value, subsequent types can be arrays, vectors
+ and structs. Note that subsequent types being indexed into can never be
+ pointers, since that would require loading the pointer before continuing
+ calculation.</p>
<p>The type of each index argument depends on the type it is indexing into.
-When indexing into a (packed) structure, only <tt>i32</tt> integer
-<b>constants</b> are allowed. When indexing into an array, pointer or vector,
-integers of any width are allowed (also non-constants).</p>
+ When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
+ <b>constants</b> are allowed. When indexing into an array, pointer or
+ vector, integers of any width are allowed, and they are not required to be
+ constant.</p>
-<p>For example, let's consider a C code fragment and how it gets
-compiled to LLVM:</p>
+<p>For example, let's consider a C code fragment and how it gets compiled to
+ LLVM:</p>
<div class="doc_code">
<pre>
%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
-define i32* %foo(%ST* %s) {
+define i32* @foo(%ST* %s) {
entry:
%reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
ret i32* %reg
</div>
<h5>Semantics:</h5>
-
<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
-type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
-}</tt>' type, a structure. The second index indexes into the third element of
-the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
-i8 }</tt>' type, another structure. The third index indexes into the second
-element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
-array. The two dimensions of the array are subscripted into, yielding an
-'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
-to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
+ type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
+ }</tt>' type, a structure. The second index indexes into the third element
+ of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
+ i8 }</tt>' type, another structure. The third index indexes into the second
+ element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
+ array. The two dimensions of the array are subscripted into, yielding an
+ '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
+ pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
-<p>Note that it is perfectly legal to index partially through a
-structure, returning a pointer to an inner element. Because of this,
-the LLVM code for the given testcase is equivalent to:</p>
+<p>Note that it is perfectly legal to index partially through a structure,
+ returning a pointer to an inner element. Because of this, the LLVM code for
+ the given testcase is equivalent to:</p>
<pre>
- define i32* %foo(%ST* %s) {
+ define i32* @foo(%ST* %s) {
%t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
%t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
%t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
}
</pre>
-<p>Note that it is undefined to access an array out of bounds: array
-and pointer indexes must always be within the defined bounds of the
-array type when accessed with an instruction that dereferences the
-pointer (e.g. a load or store instruction). The one exception for
-this rule is zero length arrays. These arrays are defined to be
-accessible as variable length arrays, which requires access beyond the
-zero'th element.</p>
+<p>If the <tt>inbounds</tt> keyword is present, the result value of the
+ <tt>getelementptr</tt> is undefined if the base pointer is not an
+ <i>in bounds</i> address of an allocated object, or if any of the addresses
+ that would be formed by successive addition of the offsets implied by the
+ indices to the base address with infinitely precise arithmetic are not an
+ <i>in bounds</i> address of that allocated object.
+ The <i>in bounds</i> addresses for an allocated object are all the addresses
+ that point into the object, plus the address one byte past the end.</p>
-<p>The getelementptr instruction is often confusing. For some more insight
-into how it works, see <a href="GetElementPtr.html">the getelementptr
-FAQ</a>.</p>
+<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
+ the base address with silently-wrapping two's complement arithmetic, and
+ the result value of the <tt>getelementptr</tt> may be outside the object
+ pointed to by the base pointer. The result value may not necessarily be
+ used to access memory though, even if it happens to point into allocated
+ storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
+ section for more information.</p>
-<h5>Example:</h5>
+<p>The getelementptr instruction is often confusing. For some more insight into
+ how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
+<h5>Example:</h5>
<pre>
<i>; yields [12 x i8]*:aptr</i>
%aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
<i>; yields i32*:iptr</i>
%iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
</pre>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
</div>
+
<div class="doc_text">
+
<p>The instructions in this category are the conversion instructions (casting)
-which all take a single operand and a type. They perform various bit conversions
-on the operand.</p>
+ which all take a single operand and a type. They perform various bit
+ conversions on the operand.</p>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-<p>
-The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
-</p>
+<p>The '<tt>trunc</tt>' instruction truncates its operand to the
+ type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>
-The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
-be an <a href="#t_integer">integer</a> type, and a type that specifies the size
-and type of the result, which must be an <a href="#t_integer">integer</a>
-type. The bit size of <tt>value</tt> must be larger than the bit size of
-<tt>ty2</tt>. Equal sized types are not allowed.</p>
+<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
+ be an <a href="#t_integer">integer</a> type, and a type that specifies the
+ size and type of the result, which must be
+ an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
+ be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
+ allowed.</p>
<h5>Semantics:</h5>
-<p>
-The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
-and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
-larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
-It will always truncate bits.</p>
+<p>The '<tt>trunc</tt>' instruction truncates the high order bits
+ in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
+ source size must be larger than the destination size, <tt>trunc</tt> cannot
+ be a <i>no-op cast</i>. It will always truncate bits.</p>
<h5>Example:</h5>
<pre>
%X = trunc i32 257 to i8 <i>; yields i8:1</i>
%Y = trunc i32 123 to i1 <i>; yields i1:true</i>
- %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
+ %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-<p>The '<tt>zext</tt>' instruction zero extends its operand to type
-<tt>ty2</tt>.</p>
+<p>The '<tt>zext</tt>' instruction zero extends its operand to type
+ <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
-<a href="#t_integer">integer</a> type, and a type to cast it to, which must
-also be of <a href="#t_integer">integer</a> type. The bit size of the
-<tt>value</tt> must be smaller than the bit size of the destination type,
-<tt>ty2</tt>.</p>
+<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
+
<a href="#t_integer">integer</a> type, and a type to cast it to, which must
+
also be of <a href="#t_integer">integer</a> type. The bit size of the
+ <tt>value</tt> must be smaller than the bit size of the destination type,
+ <tt>ty2</tt>.</p>
<h5>Semantics:</h5>
<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
-bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
+ bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
<p>When zero extending from i1, the result will always be either 0 or 1.</p>
%X = zext i32 257 to i64 <i>; yields i64:257</i>
%Y = zext i1 true to i32 <i>; yields i32:1</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>
-The '<tt>sext</tt>' instruction takes a value to cast, which must be of
-<a href="#t_integer">integer</a> type, and a type to cast it to, which must
-also be of <a href="#t_integer">integer</a> type. The bit size of the
-<tt>value</tt> must be smaller than the bit size of the destination type,
-<tt>ty2</tt>.</p>
+<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
+ <a href="#t_integer">integer</a> type, and a type to cast it to, which must
+ also be of <a href="#t_integer">integer</a> type. The bit size of the
+ <tt>value</tt> must be smaller than the bit size of the destination type,
+ <tt>ty2</tt>.</p>
<h5>Semantics:</h5>
-<p>
-The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
-bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
-the type <tt>ty2</tt>.</p>
+<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
+ bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
+ of the type <tt>ty2</tt>.</p>
<p>When sign extending from i1, the extension always results in -1 or 0.</p>
%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
%Y = sext i1 true to i32 <i>; yields i32:-1</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i>
</pre>
<h5>Overview:</h5>
<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
-<tt>ty2</tt>.</p>
-
+ <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
- point</a> value to cast and a <a href="#t_floating">floating point</a> type to
-cast it to. The size of <tt>value</tt> must be larger than the size of
-<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
-<i>no-op cast</i>.</p>
+ point</a> value to cast and a <a href="#t_floating">floating point</a> type
+ to cast it to. The size of <tt>value</tt> must be larger than the size of
+ <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
+ <i>no-op cast</i>.</p>
<h5>Semantics:</h5>
-<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
-<a href="#t_floating">floating point</a> type to a smaller
-<a href="#t_floating">floating point</a> type. If the value cannot fit within
-the destination type, <tt>ty2</tt>, then the results are undefined.</p>
+<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
+ <a href="#t_floating">floating point</a> type to a smaller
+ <a href="#t_floating">floating point</a> type. If the value cannot fit
+ within the destination type, <tt>ty2</tt>, then the results are
+ undefined.</p>
<h5>Example:</h5>
<pre>
%X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
%Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<h5>Overview:</h5>
<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
-floating point value.</p>
+ floating point value.</p>
<h5>Arguments:</h5>
-<p>The '<tt>fpext</tt>' instruction takes a
-<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
-
and a <a href="#t_floating">floating point</a> type to cast it to. The source
-type must be smaller than the destination type.</p>
+<p>The '<tt>fpext</tt>' instruction takes a
+ <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
+
a <a href="#t_floating">floating point</a> type to cast it to. The source
+ type must be smaller than the destination type.</p>
<h5>Semantics:</h5>
<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
-<a href="#t_floating">floating point</a> type to a larger
-<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
-used to make a <i>no-op cast</i> because it always changes bits. Use
-<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
+ <a href="#t_floating">floating point</a> type to a larger
+ <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
+ used to make a <i>no-op cast</i> because it always changes bits. Use
+ <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
<h5>Example:</h5>
<pre>
%X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
%Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<h5>Overview:</h5>
<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
-unsigned integer equivalent of type <tt>ty2</tt>.
-</p>
+ unsigned integer equivalent of type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
-scalar or vector <a href="#t_floating">floating point</a> value, and a type
-to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
-type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
-vector integer type with the same number of elements as <tt>ty</tt></p>
+<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
+ scalar or vector <a href="#t_floating">floating point</a> value, and a type
+ to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
+ type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
+ vector integer type with the same number of elements as <tt>ty</tt></p>
<h5>Semantics:</h5>
-<p> The '<tt>fptoui</tt>' instruction converts its
-<a href="#t_floating">floating point</a> operand into the nearest (rounding
-towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
-the results are undefined.</p>
+<p>The '<tt>fptoui</tt>' instruction converts its
+
<a href="#t_floating">floating point</a> operand into the nearest (rounding
+ towards zero) unsigned integer value. If the value cannot fit
+ in <tt>ty2</tt>, the results are undefined.</p>
<h5>Example:</h5>
<pre>
%X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
%Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
- %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
+ %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-<p>The '<tt>fptosi</tt>' instruction converts
-<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
-</p>
+<p>The '<tt>fptosi</tt>' instruction converts
+ <a href="#t_floating">floating point</a> <tt>value</tt> to
+ type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
-scalar or vector <a href="#t_floating">floating point</a> value, and a type
-to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
-type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
-vector integer type with the same number of elements as <tt>ty</tt></p>
+<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
+ scalar or vector <a href="#t_floating">floating point</a> value, and a type
+ to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
+ type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
+ vector integer type with the same number of elements as <tt>ty</tt></p>
<h5>Semantics:</h5>
-<p>The '<tt>fptosi</tt>' instruction converts its
-<a href="#t_floating">floating point</a> operand into the nearest (rounding
-towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
-the results are undefined.</p>
+<p>The '<tt>fptosi</tt>' instruction converts its
+
<a href="#t_floating">floating point</a> operand into the nearest (rounding
+ towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
+ the results are undefined.</p>
<h5>Example:</h5>
<pre>
%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
%Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
- %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
+ %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<h5>Overview:</h5>
<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
-integer and converts that value to the <tt>ty2</tt> type.</p>
+ integer and converts that value to the <tt>ty2</tt> type.</p>
<h5>Arguments:</h5>
<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
-scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
-to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
-type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
-floating point type with the same number of elements as <tt>ty</tt></p>
+ scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
+ it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
+ type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
+ floating point type with the same number of elements as <tt>ty</tt></p>
<h5>Semantics:</h5>
<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
-integer quantity and converts it to the corresponding floating point value. If
-the value cannot fit in the floating point value, the results are undefined.</p>
+ integer quantity and converts it to the corresponding floating point
+ value. If the value cannot fit in the floating point value, the results are
+ undefined.</p>
<h5>Example:</h5>
<pre>
%X = uitofp i32 257 to float <i>; yields float:257.0</i>
%Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
-integer and converts that value to the <tt>ty2</tt> type.</p>
+<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
+ and converts that value to the <tt>ty2</tt> type.</p>
<h5>Arguments:</h5>
<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
-scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
-to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
-type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
-floating point type with the same number of elements as <tt>ty</tt></p>
+ scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
+ it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
+ type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
+ floating point type with the same number of elements as <tt>ty</tt></p>
<h5>Semantics:</h5>
-<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
-integer quantity and converts it to the corresponding floating point value. If
-the value cannot fit in the floating point value, the results are undefined.</p>
+<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
+ quantity and converts it to the corresponding floating point value. If the
+ value cannot fit in the floating point value, the results are undefined.</p>
<h5>Example:</h5>
<pre>
%X = sitofp i32 257 to float <i>; yields float:257.0</i>
%Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
-the integer type <tt>ty2</tt>.</p>
+<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
+ the integer type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
-must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
-<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
+<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
+
must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
+
<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
<h5>Semantics:</h5>
<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
-<tt>ty2</tt> by interpreting the pointer value as an integer and either
-truncating or zero extending that value to the size of the integer type. If
-<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
-<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
-are the same size, then nothing is done (<i>no-op cast</i>) other than a type
-change.</p>
+ <tt>ty2</tt> by interpreting the pointer value as an integer and either
+ truncating or zero extending that value to the size of the integer type. If
+ <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
+ <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
+ are the same size, then nothing is done (<i>no-op cast</i>) other than a type
+ change.</p>
<h5>Example:</h5>
<pre>
%X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
%Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
-a pointer type, <tt>ty2</tt>.</p>
+<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
+ pointer type, <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
-value to cast, and a type to cast it to, which must be a
-<a href="#t_pointer">pointer</a> type.</p>
+ value to cast, and a type to cast it to, which must be a
+
<a href="#t_pointer">pointer</a> type.</p>
<h5>Semantics:</h5>
<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
-<tt>ty2</tt> by applying either a zero extension or a truncation depending on
-the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
-size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
-the size of a pointer then a zero extension is done. If they are the same size,
-nothing is done (<i>no-op cast</i>).</p>
+ <tt>ty2</tt> by applying either a zero extension or a truncation depending on
+ the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
+ size of a pointer then a truncation is done. If <tt>value</tt> is smaller
+ than the size of a pointer then a zero extension is done. If they are the
+ same size, nothing is done (<i>no-op cast</i>).</p>
<h5>Example:</h5>
<pre>
%X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
- %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
- %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
+ %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
+ %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
-<tt>ty2</tt> without changing any bits.</p>
+ <tt>ty2</tt> without changing any bits.</p>
<h5>Arguments:</h5>
-
-<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
-a non-aggregate first class value, and a type to cast it to, which must also be
-a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
-<tt>value</tt>
-and the destination type, <tt>ty2</tt>, must be identical. If the source
-type is a pointer, the destination type must also be a pointer. This
-instruction supports bitwise conversion of vectors to integers and to vectors
-of other types (as long as they have the same size).</p>
+<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
+ non-aggregate first class value, and a type to cast it to, which must also be
+ a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
+ of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
+ identical. If the source type is a pointer, the destination type must also be
+ a pointer. This instruction supports bitwise conversion of vectors to
+ integers and to vectors of other types (as long as they have the same
+ size).</p>
<h5>Semantics:</h5>
<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
-<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
-this conversion. The conversion is done as if the <tt>value</tt> had been
-stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
-converted to other pointer types with this instruction. To convert pointers to
-other types, use the <a href="#i_inttoptr">inttoptr</a> or
-<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
+ <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
+ this conversion. The conversion is done as if the <tt>value</tt> had been
+ stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
+ be converted to other pointer types with this instruction. To convert
+ pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
+
<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
<h5>Example:</h5>
<pre>
%X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
- %Z = bitcast <2 x int> %V to i64; <i>; yields i64: %V</i>
+ %Z = bitcast <2 x int> %V to i64; <i>; yields i64: %V</i>
</pre>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
+
<div class="doc_text">
-<p>The instructions in this category are the "miscellaneous"
-instructions, which defy better classification.</p>
+
+<p>The instructions in this category are the "miscellaneous" instructions, which
+ defy better classification.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = icmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1>}:result</i>
+<pre>
+ <result> = icmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1>}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>icmp</tt>' instruction returns a boolean value or
-a vector of boolean values based on comparison
-of its two integer, integer vector, or pointer operands.</p>
+<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
+ boolean values based on comparison of its two integer, integer vector, or
+ pointer operands.</p>
+
<h5>Arguments:</h5>
<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
-the condition code indicating the kind of comparison to perform. It is not
-a value, just a keyword. The possible condition code are:
-</p>
+ the condition code indicating the kind of comparison to perform. It is not a
+ value, just a keyword. The possible condition code are:</p>
+
<ol>
<li><tt>eq</tt>: equal</li>
<li><tt>ne</tt>: not equal </li>
<li><tt>slt</tt>: signed less than</li>
<li><tt>sle</tt>: signed less or equal</li>
</ol>
+
<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
-<a href="#t_pointer">pointer</a>
-or integer <a href="#t_vector">vector</a> typed.
-They must also be identical types.</p>
+ <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
+ typed. They must also be identical types.</p>
+
<h5>Semantics:</h5>
-<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
-the condition code given as <tt>cond</tt>. The comparison performed always
-yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
-</p>
+<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
+ condition code given as <tt>cond</tt>. The comparison performed always yields
+ either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
+ result, as follows:</p>
+
<ol>
- <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
- <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
- </li>
- <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
- <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
+ <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
+ <tt>false</tt> otherwise. No sign interpretation is necessary or
+ performed.</li>
+
+ <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
+ <tt>false</tt> otherwise. No sign interpretation is necessary or
+ performed.</li>
+
<li><tt>ugt</tt>: interprets the operands as unsigned values and yields
- <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
+
<li><tt>uge</tt>: interprets the operands as unsigned values and yields
- <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is greater than or equal
+ to <tt>op2</tt>.</li>
+
<li><tt>ult</tt>: interprets the operands as unsigned values and yields
- <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
+
<li><tt>ule</tt>: interprets the operands as unsigned values and yields
- <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
+
<li><tt>sgt</tt>: interprets the operands as signed values and yields
- <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
+
<li><tt>sge</tt>: interprets the operands as signed values and yields
- <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is greater than or equal
+ to <tt>op2</tt>.</li>
+
<li><tt>slt</tt>: interprets the operands as signed values and yields
- <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
+
<li><tt>sle</tt>: interprets the operands as signed values and yields
- <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
+ <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
</ol>
+
<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
-values are compared as if they were integers.</p>
-<p>If the operands are integer vectors, then they are compared
-element by element. The result is an <tt>i1</tt> vector with
-the same number of elements as the values being compared.
-Otherwise, the result is an <tt>i1</tt>.
-</p>
+ values are compared as if they were integers.</p>
+
+<p>If the operands are integer vectors, then they are compared element by
+ element. The result is an <tt>i1</tt> vector with the same number of elements
+ as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
<h5>Example:</h5>
-<pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
+<pre>
+ <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
<result> = icmp ne float* %X, %X <i>; yields: result=false</i>
<result> = icmp ult i16 4, 5 <i>; yields: result=true</i>
<result> = icmp sgt i16 4, 5 <i>; yields: result=false</i>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> <result> = fcmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1>}:result</i>
+<pre>
+ <result> = fcmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1>}:result</i>
</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>fcmp</tt>' instruction returns a boolean value
-or vector of boolean values based on comparison
-of its operands.</p>
-<p>
-If the operands are floating point scalars, then the result
-type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
-</p>
-<p>If the operands are floating point vectors, then the result type
-is a vector of boolean with the same number of elements as the
-operands being compared.</p>
+<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
+ values based on comparison of its operands.</p>
+
+<p>If the operands are floating point scalars, then the result type is a boolean
+(<a href="#t_integer"><tt>i1</tt></a>).</p>
+
+<p>If the operands are floating point vectors, then the result type is a vector
+ of boolean with the same number of elements as the operands being
+ compared.</p>
+
<h5>Arguments:</h5>
<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
-the condition code indicating the kind of comparison to perform. It is not
-a value, just a keyword. The possible condition code are:</p>
+ the condition code indicating the kind of comparison to perform. It is not a
+ value, just a keyword. The possible condition code are:</p>
+
<ol>
<li><tt>false</tt>: no comparison, always returns false</li>
<li><tt>oeq</tt>: ordered and equal</li>
<li><tt>uno</tt>: unordered (either nans)</li>
<li><tt>true</tt>: no comparison, always returns true</li>
</ol>
+
<p><i>Ordered</i> means that neither operand is a QNAN while
-<i>unordered</i> means that either operand may be a QNAN.</p>
-<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
-either a <a href="#t_floating">floating point</a> type
-or a <a href="#t_vector">vector</a> of floating point type.
-They must have identical types.</p>
+ <i>unordered</i> means that either operand may be a QNAN.</p>
+
+<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
+ a <a href="#t_floating">floating point</a> type or
+ a <a href="#t_vector">vector</a> of floating point type. They must have
+ identical types.</p>
+
<h5>Semantics:</h5>
<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
-according to the condition code given as <tt>cond</tt>.
-If the operands are vectors, then the vectors are compared
-element by element.
-Each comparison performed
-always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
+ according to the condition code given as <tt>cond</tt>. If the operands are
+ vectors, then the vectors are compared element by element. Each comparison
+ performed always yields an <a href="#t_integer">i1</a> result, as
+ follows:</p>
+
<ol>
<li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
- <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
- <tt>op1</tt> is equal to <tt>op2</tt>.</li>
+
+ <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
+ <tt>op1</tt> is equal to <tt>op2</tt>.</li>
+
<li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
- <tt>op1</tt> is greather than <tt>op2</tt>.</li>
- <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
- <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
- <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
- <tt>op1</tt> is less than <tt>op2</tt>.</li>
- <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
- <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
- <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
- <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
+ <tt>op1</tt> is greather than <tt>op2</tt>.</li>
+
+ <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
+ <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
+
+ <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
+ <tt>op1</tt> is less than <tt>op2</tt>.</li>
+
+ <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
+ <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
+
+ <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
+ <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
+
<li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
- <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
- <tt>op1</tt> is equal to <tt>op2</tt>.</li>
- <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
- <tt>op1</tt> is greater than <tt>op2</tt>.</li>
- <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
- <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
- <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
- <tt>op1</tt> is less than <tt>op2</tt>.</li>
- <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
- <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
- <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
- <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
+
+ <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
+ <tt>op1</tt> is equal to <tt>op2</tt>.</li>
+
+ <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
+ <tt>op1</tt> is greater than <tt>op2</tt>.</li>
+
+ <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
+ <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
+
+ <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
+ <tt>op1</tt> is less than <tt>op2</tt>.</li>
+
+ <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
+ <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
+
+ <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
+ <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
+
<li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
+
<li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
</ol>
<h5>Example:</h5>
-<pre> <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
+<pre>
+ <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
<result> = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
<result> = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
<result> = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
-</div>
-<div class="doc_text">
-<h5>Syntax:</h5>
-<pre> <result> = vicmp <cond> <ty> <op1>, <op2> <i>; yields {ty}:result</i>
-</pre>
-<h5>Overview:</h5>
-<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
-element-wise comparison of its two integer vector operands.</p>
-<h5>Arguments:</h5>
-<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
-the condition code indicating the kind of comparison to perform. It is not
-a value, just a keyword. The possible condition code are:</p>
-<ol>
- <li><tt>eq</tt>: equal</li>
- <li><tt>ne</tt>: not equal </li>
- <li><tt>ugt</tt>: unsigned greater than</li>
- <li><tt>uge</tt>: unsigned greater or equal</li>
- <li><tt>ult</tt>: unsigned less than</li>
- <li><tt>ule</tt>: unsigned less or equal</li>
- <li><tt>sgt</tt>: signed greater than</li>
- <li><tt>sge</tt>: signed greater or equal</li>
- <li><tt>slt</tt>: signed less than</li>
- <li><tt>sle</tt>: signed less or equal</li>
-</ol>
-<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
-<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
-<h5>Semantics:</h5>
-<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
-according to the condition code given as <tt>cond</tt>. The comparison yields a
-<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
-identical type as the values being compared. The most significant bit in each
-element is 1 if the element-wise comparison evaluates to true, and is 0
-otherwise. All other bits of the result are undefined. The condition codes
-are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
-instruction</a>.</p>
-
-<h5>Example:</h5>
-<pre>
- <result> = vicmp eq <2 x i32> < i32 4, i32 0>, < i32 5, i32 0> <i>; yields: result=<2 x i32> < i32 0, i32 -1 ></i>
- <result> = vicmp ult <2 x i8 > < i8 1, i8 2>, < i8 2, i8 2 > <i>; yields: result=<2 x i8> < i8 -1, i8 0 ></i>
-</pre>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
-</div>
-<div class="doc_text">
-<h5>Syntax:</h5>
-<pre> <result> = vfcmp <cond> <ty> <op1>, <op2></pre>
-<h5>Overview:</h5>
-<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
-element-wise comparison of its two floating point vector operands. The output
-elements have the same width as the input elements.</p>
-<h5>Arguments:</h5>
-<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
-the condition code indicating the kind of comparison to perform. It is not
-a value, just a keyword. The possible condition code are:</p>
-<ol>
- <li><tt>false</tt>: no comparison, always returns false</li>
- <li><tt>oeq</tt>: ordered and equal</li>
- <li><tt>ogt</tt>: ordered and greater than </li>
- <li><tt>oge</tt>: ordered and greater than or equal</li>
- <li><tt>olt</tt>: ordered and less than </li>
- <li><tt>ole</tt>: ordered and less than or equal</li>
- <li><tt>one</tt>: ordered and not equal</li>
- <li><tt>ord</tt>: ordered (no nans)</li>
- <li><tt>ueq</tt>: unordered or equal</li>
- <li><tt>ugt</tt>: unordered or greater than </li>
- <li><tt>uge</tt>: unordered or greater than or equal</li>
- <li><tt>ult</tt>: unordered or less than </li>
- <li><tt>ule</tt>: unordered or less than or equal</li>
- <li><tt>une</tt>: unordered or not equal</li>
- <li><tt>uno</tt>: unordered (either nans)</li>
- <li><tt>true</tt>: no comparison, always returns true</li>
-</ol>
-<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
-<a href="#t_floating">floating point</a> typed. They must also be identical
-types.</p>
-<h5>Semantics:</h5>
-<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
-according to the condition code given as <tt>cond</tt>. The comparison yields a
-<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
-an identical number of elements as the values being compared, and each element
-having identical with to the width of the floating point elements. The most
-significant bit in each element is 1 if the element-wise comparison evaluates to
-true, and is 0 otherwise. All other bits of the result are undefined. The
-condition codes are evaluated identically to the
-<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
-
-<h5>Example:</h5>
-<pre>
- <i>; yields: result=<2 x i32> < i32 0, i32 -1 ></i>
- <result> = vfcmp oeq <2 x float> < float 4, float 0 >, < float 5, float 0 >
-
- <i>; yields: result=<2 x i64> < i64 -1, i64 0 ></i>
- <result> = vfcmp ult <2 x double> < double 1, double 2 >, < double 2, double 2>
-</pre>
-</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_phi">'<tt>phi</tt>' Instruction</a>
<div class="doc_text">
<h5>Syntax:</h5>
+<pre>
+ <result> = phi <ty> [ <val0>, <label0>], ...
+</pre>
-<pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre>
<h5>Overview:</h5>
-<p>The '<tt>phi</tt>' instruction is used to implement the φ node in
-the SSA graph representing the function.</p>
-<h5>Arguments:</h5>
-
-<p>The type of the incoming values is specified with the first type
-field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
-as arguments, with one pair for each predecessor basic block of the
-current block. Only values of <a href="#t_firstclass">first class</a>
-type may be used as the value arguments to the PHI node. Only labels
-may be used as the label arguments.</p>
+<p>The '<tt>phi</tt>' instruction is used to implement the φ node in the
+ SSA graph representing the function.</p>
-<p>There must be no non-phi instructions between the start of a basic
-block and the PHI instructions: i.e. PHI instructions must be first in
-a basic block.</p>
-
-<p>For the purposes of the SSA form, the use of each incoming value is
-deemed to occur on the edge from the corresponding predecessor block
-to the current block (but after any definition of an '<tt>invoke</tt>'
-instruction's return value on the same edge).</p>
+<h5>Arguments:</h5>
+<p>The type of the incoming values is specified with the first type field. After
+ this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
+ one pair for each predecessor basic block of the current block. Only values
+ of <a href="#t_firstclass">first class</a> type may be used as the value
+ arguments to the PHI node. Only labels may be used as the label
+ arguments.</p>
+
+<p>There must be no non-phi instructions between the start of a basic block and
+ the PHI instructions: i.e. PHI instructions must be first in a basic
+ block.</p>
+
+<p>For the purposes of the SSA form, the use of each incoming value is deemed to
+ occur on the edge from the corresponding predecessor block to the current
+ block (but after any definition of an '<tt>invoke</tt>' instruction's return
+ value on the same edge).</p>
<h5>Semantics:</h5>
-
<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
-specified by the pair corresponding to the predecessor basic block that executed
-just prior to the current block.</p>
+ specified by the pair corresponding to the predecessor basic block that
+ executed just prior to the current block.</p>
<h5>Example:</h5>
<pre>
%nextindvar = add i32 %indvar, 1
br label %Loop
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<result> = select <i>selty</i> <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>select</tt>' instruction is used to choose one value based on a
-condition, without branching.
-</p>
+<p>The '<tt>select</tt>' instruction is used to choose one value based on a
+ condition, without branching.</p>
<h5>Arguments:</h5>
-
-<p>
-The '<tt>select</tt>' instruction requires an 'i1' value or
-a vector of 'i1' values indicating the
-condition, and two values of the same <a href="#t_firstclass">first class</a>
-type. If the val1/val2 are vectors and
-the condition is a scalar, then entire vectors are selected, not
-individual elements.
-</p>
+<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
+ values indicating the condition, and two values of the
+ same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
+ vectors and the condition is a scalar, then entire vectors are selected, not
+ individual elements.</p>
<h5>Semantics:</h5>
+<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
+ first value argument; otherwise, it returns the second value argument.</p>
-<p>
-If the condition is an i1 and it evaluates to 1, the instruction returns the first
-value argument; otherwise, it returns the second value argument.
-</p>
-<p>
-If the condition is a vector of i1, then the value arguments must
-be vectors of the same size, and the selection is done element
-by element.
-</p>
+<p>If the condition is a vector of i1, then the value arguments must be vectors
+ of the same size, and the selection is done element by element.</p>
<h5>Example:</h5>
-
<pre>
%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
</pre>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_call">'<tt>call</tt>' Instruction</a>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
<h5>Arguments:</h5>
-
<p>This instruction requires several arguments:</p>
<ol>
- <li>
- <p>The optional "tail" marker indicates whether the callee function accesses
- any allocas or varargs in the caller. If the "tail" marker is present, the
- function call is eligible for tail call optimization. Note that calls may
- be marked "tail" even if they do not occur before a <a
- href="#i_ret"><tt>ret</tt></a> instruction.</p>
- </li>
- <li>
- <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
- convention</a> the call should use. If none is specified, the call defaults
- to using C calling conventions.</p>
+ <li>The optional "tail" marker indicates that the callee function does not
+ access any allocas or varargs in the caller. Note that calls may be
+ marked "tail" even if they do not occur before
+ a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
+ present, the function call is eligible for tail call optimization,
+ but <a href="CodeGenerator.html#tailcallopt">might not in fact be
+ optimized into a jump</a>. As of this writing, the extra requirements for
+ a call to actually be optimized are:
+ <ul>
+ <li>Caller and callee both have the calling
+ convention <tt>fastcc</tt>.</li>
+ <li>The call is in tail position (ret immediately follows call and ret
+ uses value of call or is void).</li>
+ <li>Option <tt>-tailcallopt</tt> is enabled,
+ or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
+ <li><a href="CodeGenerator.html#tailcallopt">Platform specific
+ constraints are met.</a></li>
+ </ul>
</li>
- <li>
- <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
- return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
- and '<tt>inreg</tt>' attributes are valid here.</p>
- </li>
+ <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
+ convention</a> the call should use. If none is specified, the call
+ defaults to using C calling conventions. The calling convention of the
+ call must match the calling convention of the target function, or else the
+ behavior is undefined.</li>
- <li>
- <p>'<tt>ty</tt>': the type of the call instruction itself which is also
- the type of the return value. Functions that return no value are marked
- <tt><a href="#t_void">void</a></tt>.</p>
- </li>
- <li>
- <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
- value being invoked. The argument types must match the types implied by
- this signature. This type can be omitted if the function is not varargs
- and if the function type does not return a pointer to a function.</p>
- </li>
- <li>
- <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
- be invoked. In most cases, this is a direct function invocation, but
- indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
- to function value.</p>
- </li>
- <li>
- <p>'<tt>function args</tt>': argument list whose types match the
- function signature argument types. All arguments must be of
- <a href="#t_firstclass">first class</a> type. If the function signature
- indicates the function accepts a variable number of arguments, the extra
- arguments can be specified.</p>
- </li>
- <li>
- <p>The optional <a href="#fnattrs">function attributes</a> list. Only
- '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
- '<tt>readnone</tt>' attributes are valid here.</p>
- </li>
+ <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
+ return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
+ '<tt>inreg</tt>' attributes are valid here.</li>
+
+ <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
+ type of the return value. Functions that return no value are marked
+ <tt><a href="#t_void">void</a></tt>.</li>
+
+ <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
+ being invoked. The argument types must match the types implied by this
+ signature. This type can be omitted if the function is not varargs and if
+ the function type does not return a pointer to a function.</li>
+
+ <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
+ be invoked. In most cases, this is a direct function invocation, but
+ indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
+ to function value.</li>
+
+ <li>'<tt>function args</tt>': argument list whose types match the function
+ signature argument types. All arguments must be of
+ <a href="#t_firstclass">first class</a> type. If the function signature
+ indicates the function accepts a variable number of arguments, the extra
+ arguments can be specified.</li>
+
+ <li>The optional <a href="#fnattrs">function attributes</a> list. Only
+ '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
+ '<tt>readnone</tt>' attributes are valid here.</li>
</ol>
<h5>Semantics:</h5>
-
-<p>The '<tt>call</tt>' instruction is used to cause control flow to
-transfer to a specified function, with its incoming arguments bound to
-the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
-instruction in the called function, control flow continues with the
-instruction after the function call, and the return value of the
-function is bound to the result argument.</p>
+<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
+ a specified function, with its incoming arguments bound to the specified
+ values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
+ function, control flow continues with the instruction after the function
+ call, and the return value of the function is bound to the result
+ argument.</p>
<h5>Example:</h5>
-
<pre>
%retval = call i32 @test(i32 %argc)
call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
%ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
</pre>
+<p>llvm treats calls to some functions with names and arguments that match the
+standard C99 library as being the C99 library functions, and may perform
+optimizations or generate code for them under that assumption. This is
+something we'd like to change in the future to provide better support for
+freestanding environments and non-C-based langauges.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
<resultval> = va_arg <va_list*> <arglist>, <argty>
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
-the "variable argument" area of a function call. It is used to implement the
-<tt>va_arg</tt> macro in C.</p>
+ the "variable argument" area of a function call. It is used to implement the
+ <tt>va_arg</tt> macro in C.</p>
<h5>Arguments:</h5>
-
-<p>This instruction takes a <tt>va_list*</tt> value and the type of
-the argument. It returns a value of the specified argument type and
-increments the <tt>va_list</tt> to point to the next argument. The
-actual type of <tt>va_list</tt> is target specific.</p>
+<p>This instruction takes a <tt>va_list*</tt> value and the type of the
+ argument. It returns a value of the specified argument type and increments
+ the <tt>va_list</tt> to point to the next argument. The actual type
+ of <tt>va_list</tt> is target specific.</p>
<h5>Semantics:</h5>
-
-<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
-type from the specified <tt>va_list</tt> and causes the
-<tt>va_list</tt> to point to the next argument. For more information,
-see the variable argument handling <a href="#int_varargs">Intrinsic
-Functions</a>.</p>
+<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
+ from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
+ to the next argument. For more information, see the variable argument
+ handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
<p>It is legal for this instruction to be called in a function which does not
-take a variable number of arguments, for example, the <tt>vfprintf</tt>
-function.</p>
+ take a variable number of arguments, for example, the <tt>vfprintf</tt>
+ function.</p>
-<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
-href="#intrinsics">intrinsic function</a> because it takes a type as an
-argument.</p>
+<p><tt>va_arg</tt> is an LLVM instruction instead of
+ an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
+ argument.</p>
<h5>Example:</h5>
-
<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
-<p>Note that the code generator does not yet fully support va_arg
- on many targets. Also, it does not currently support va_arg with
- aggregate types on any target.</p>
+<p>Note that the code generator does not yet fully support va_arg on many
+ targets. Also, it does not currently support va_arg with aggregate types on
+ any target.</p>
</div>
<div class="doc_text">
<p>LLVM supports the notion of an "intrinsic function". These functions have
-well known names and semantics and are required to follow certain restrictions.
-Overall, these intrinsics represent an extension mechanism for the LLVM
-language that does not require changing all of the transformations in LLVM when
-adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
+ well known names and semantics and are required to follow certain
+ restrictions. Overall, these intrinsics represent an extension mechanism for
+ the LLVM language that does not require changing all of the transformations
+ in LLVM when adding to the language (or the bitcode reader/writer, the
+ parser, etc...).</p>
<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
-prefix is reserved in LLVM for intrinsic names; thus, function names may not
-begin with this prefix. Intrinsic functions must always be external functions:
-you cannot define the body of intrinsic functions. Intrinsic functions may
-only be used in call or invoke instructions: it is illegal to take the address
-of an intrinsic function. Additionally, because intrinsic functions are part
-of the LLVM language, it is required if any are added that they be documented
-here.</p>
-
-<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
-a family of functions that perform the same operation but on different data
-types. Because LLVM can represent over 8 million different integer types,
-overloading is used commonly to allow an intrinsic function to operate on any
-integer type. One or more of the argument types or the result type can be
-overloaded to accept any integer type. Argument types may also be defined as
-exactly matching a previous argument's type or the result type. This allows an
-intrinsic function which accepts multiple arguments, but needs all of them to
-be of the same type, to only be overloaded with respect to a single argument or
-the result.</p>
-
-<p>Overloaded intrinsics will have the names of its overloaded argument types
-encoded into its function name, each preceded by a period. Only those types
-which are overloaded result in a name suffix. Arguments whose type is matched
-against another type do not. For example, the <tt>llvm.ctpop</tt> function can
-take an integer of any width and returns an integer of exactly the same integer
-width. This leads to a family of functions such as
-<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
-Only one type, the return type, is overloaded, and only one type suffix is
-required. Because the argument's type is matched against the return type, it
-does not require its own name suffix.</p>
-
-<p>To learn how to add an intrinsic function, please see the
-<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
-</p>
+ prefix is reserved in LLVM for intrinsic names; thus, function names may not
+ begin with this prefix. Intrinsic functions must always be external
+ functions: you cannot define the body of intrinsic functions. Intrinsic
+ functions may only be used in call or invoke instructions: it is illegal to
+ take the address of an intrinsic function. Additionally, because intrinsic
+ functions are part of the LLVM language, it is required if any are added that
+ they be documented here.</p>
+
+<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
+ family of functions that perform the same operation but on different data
+ types. Because LLVM can represent over 8 million different integer types,
+ overloading is used commonly to allow an intrinsic function to operate on any
+ integer type. One or more of the argument types or the result type can be
+ overloaded to accept any integer type. Argument types may also be defined as
+ exactly matching a previous argument's type or the result type. This allows
+ an intrinsic function which accepts multiple arguments, but needs all of them
+ to be of the same type, to only be overloaded with respect to a single
+ argument or the result.</p>
+
+<p>Overloaded intrinsics will have the names of its overloaded argument types
+ encoded into its function name, each preceded by a period. Only those types
+ which are overloaded result in a name suffix. Arguments whose type is matched
+ against another type do not. For example, the <tt>llvm.ctpop</tt> function
+ can take an integer of any width and returns an integer of exactly the same
+ integer width. This leads to a family of functions such as
+ <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
+ %val)</tt>. Only one type, the return type, is overloaded, and only one type
+ suffix is required. Because the argument's type is matched against the return
+ type, it does not require its own name suffix.</p>
+
+<p>To learn how to add an intrinsic function, please see the
+ <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
</div>
<div class="doc_text">
-<p>Variable argument support is defined in LLVM with the <a
- href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
-intrinsic functions. These functions are related to the similarly
-named macros defined in the <tt><stdarg.h></tt> header file.</p>
+<p>Variable argument support is defined in LLVM with
+ the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
+ intrinsic functions. These functions are related to the similarly named
+ macros defined in the <tt><stdarg.h></tt> header file.</p>
-<p>All of these functions operate on arguments that use a
-target-specific value type "<tt>va_list</tt>". The LLVM assembly
-language reference manual does not define what this type is, so all
-transformations should be prepared to handle these functions regardless of
-the type used.</p>
+<p>All of these functions operate on arguments that use a target-specific value
+ type "<tt>va_list</tt>". The LLVM assembly language reference manual does
+ not define what this type is, so all transformations should be prepared to
+ handle these functions regardless of the type used.</p>
<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
-instruction and the variable argument handling intrinsic functions are
-used.</p>
+ instruction and the variable argument handling intrinsic functions are
+ used.</p>
<div class="doc_code">
<pre>
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> declare void %llvm.va_start(i8* <arglist>)<br></pre>
+<pre>
+ declare void %llvm.va_start(i8* <arglist>)
+</pre>
+
<h5>Overview:</h5>
-<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
-<tt>*<arglist></tt> for subsequent use by <tt><a
-href="#i_va_arg">va_arg</a></tt>.</p>
+<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*<arglist></tt>
+ for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
<h5>Arguments:</h5>
-
<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
-macro available in C. In a target-dependent way, it initializes the
-<tt>va_list</tt> element to which the argument points, so that the next call to
-<tt>va_arg</tt> will produce the first variable argument passed to the function.
-Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
-last argument of the function as the compiler can figure that out.</p>
+ macro available in C. In a target-dependent way, it initializes
+ the <tt>va_list</tt> element to which the argument points, so that the next
+ call to <tt>va_arg</tt> will produce the first variable argument passed to
+ the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
+ need to know the last argument of the function as the compiler can figure
+ that out.</p>
</div>
</div>
<div class="doc_text">
+
<h5>Syntax:</h5>
-<pre> declare void @llvm.va_end(i8* <arglist>)<br></pre>
-<h5>Overview:</h5>
+<pre>
+ declare void @llvm.va_end(i8* <arglist>)
+</pre>
+<h5>Overview:</h5>
<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
-which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
-or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
+ which has been initialized previously
+ with <tt><a href="#int_va_start">llvm.va_start</a></tt>
+ or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
<h5>Arguments:</h5>
-
<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
-macro available in C. In a target-dependent way, it destroys the
-<tt>va_list</tt> element to which the argument points. Calls to <a
-href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
-<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
-<tt>llvm.va_end</tt>.</p>
+ macro available in C. In a target-dependent way, it destroys
+ the <tt>va_list</tt> element to which the argument points. Calls
+ to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
+ and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
+ with calls to <tt>llvm.va_end</tt>.</p>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
-from the source argument list to the destination argument list.</p>
+ from the source argument list to the destination argument list.</p>
<h5>Arguments:</h5>
-
<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
-The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
-
+ The second argument is a pointer to a <tt>va_list</tt> element to copy
+ from.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
-macro available in C. In a target-dependent way, it copies the source
-<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
-intrinsic is necessary because the <tt><a href="#int_va_start">
-llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
-example, memory allocation.</p>
+ macro available in C. In a target-dependent way, it copies the
+ source <tt>va_list</tt> element into the destination <tt>va_list</tt>
+ element. This intrinsic is necessary because
+ the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
+ arbitrarily complex and require, for example, memory allocation.</p>
</div>
<div class="doc_text">
-<p>
-LLVM support for <a href="GarbageCollection.html">Accurate Garbage
+<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Collection</a> (GC) requires the implementation and generation of these
-intrinsics.
-These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
-stack</a>, as well as garbage collector implementations that require <a
-href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
-Front-ends for type-safe garbage collected languages should generate these
-intrinsics to make use of the LLVM garbage collectors. For more details, see <a
-href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
-</p>
+intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
+roots on the stack</a>, as well as garbage collector implementations that
+require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
+barriers. Front-ends for type-safe garbage collected languages should generate
+these intrinsics to make use of the LLVM garbage collectors. For more details,
+see <a href="GarbageCollection.html">Accurate Garbage Collection with
+LLVM</a>.</p>
-<p>The garbage collection intrinsics only operate on objects in the generic
- address space (address space zero).</p>
+<p>The garbage collection intrinsics only operate on objects in the generic
+ address space (address space zero).</p>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
-the code generator, and allows some metadata to be associated with it.</p>
+ the code generator, and allows some metadata to be associated with it.</p>
<h5>Arguments:</h5>
-
<p>The first argument specifies the address of a stack object that contains the
-root pointer. The second pointer (which must be either a constant or a global
-value address) contains the meta-data to be associated with the root.</p>
+ root pointer. The second pointer (which must be either a constant or a
+ global value address) contains the meta-data to be associated with the
+ root.</p>
<h5>Semantics:</h5>
-
<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
-location. At compile-time, the code generator generates information to allow
-the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
-intrinsic may only be used in a function which <a href="#gc">specifies a GC
-algorithm</a>.</p>
+ location. At compile-time, the code generator generates information to allow
+ the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
+
intrinsic may only be used in a function which <a href="#gc">specifies a GC
+ algorithm</a>.</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
-locations, allowing garbage collector implementations that require read
-barriers.</p>
+ locations, allowing garbage collector implementations that require read
+ barriers.</p>
<h5>Arguments:</h5>
-
<p>The second argument is the address to read from, which should be an address
-allocated from the garbage collector. The first object is a pointer to the
-start of the referenced object, if needed by the language runtime (otherwise
-null).</p>
+ allocated from the garbage collector. The first object is a pointer to the
+ start of the referenced object, if needed by the language runtime (otherwise
+ null).</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
-instruction, but may be replaced with substantially more complex code by the
-garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
-may only be used in a function which <a href="#gc">specifies a GC
-algorithm</a>.</p>
+ instruction, but may be replaced with substantially more complex code by the
+ garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
+
may only be used in a function which <a href="#gc">specifies a GC
+ algorithm</a>.</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
<div class="doc_text">
<h5>Syntax:</h5>
-
<pre>
declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
-locations, allowing garbage collector implementations that require write
-barriers (such as generational or reference counting collectors).</p>
+ locations, allowing garbage collector implementations that require write
+ barriers (such as generational or reference counting collectors).</p>
<h5>Arguments:</h5>
-
<p>The first argument is the reference to store, the second is the start of the
-object to store it to, and the third is the address of the field of Obj to
-store to. If the runtime does not require a pointer to the object, Obj may be
-null.</p>
+ object to store it to, and the third is the address of the field of Obj to
+ store to. If the runtime does not require a pointer to the object, Obj may
+ be null.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
-instruction, but may be replaced with substantially more complex code by the
-garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
-may only be used in a function which <a href="#gc">specifies a GC
-algorithm</a>.</p>
+ instruction, but may be replaced with substantially more complex code by the
+ garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
+
may only be used in a function which <a href="#gc">specifies a GC
+ algorithm</a>.</p>
</div>
-
-
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="int_codegen">Code Generator Intrinsics</a>
</div>
<div class="doc_text">
-<p>
-These intrinsics are provided by LLVM to expose special features that may only
-be implemented with code generator support.
-</p>
+
+<p>These intrinsics are provided by LLVM to expose special features that may
+ only be implemented with code generator support.</p>
</div>
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
-target-specific value indicating the return address of the current function
-or one of its callers.
-</p>
+<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
+ target-specific value indicating the return address of the current function
+ or one of its callers.</p>
<h5>Arguments:</h5>
-
-<p>
-The argument to this intrinsic indicates which function to return the address
-for. Zero indicates the calling function, one indicates its caller, etc. The
-argument is <b>required</b> to be a constant integer value.
-</p>
+<p>The argument to this intrinsic indicates which function to return the address
+ for. Zero indicates the calling function, one indicates its caller, etc.
+ The argument is <b>required</b> to be a constant integer value.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
+ indicating the return address of the specified call frame, or zero if it
+ cannot be identified. The value returned by this intrinsic is likely to be
+ incorrect or 0 for arguments other than zero, so it should only be used for
+ debugging purposes.</p>
-<p>
-The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
-the return address of the specified call frame, or zero if it cannot be
-identified. The value returned by this intrinsic is likely to be incorrect or 0
-for arguments other than zero, so it should only be used for debugging purposes.
-</p>
+<p>Note that calling this intrinsic does not prevent function inlining or other
+ aggressive transformations, so the value returned may not be that of the
+ obvious source-language caller.</p>
-<p>
-Note that calling this intrinsic does not prevent function inlining or other
-aggressive transformations, so the value returned may not be that of the obvious
-source-language caller.
-</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
-target-specific frame pointer value for the specified stack frame.
-</p>
+<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
+ target-specific frame pointer value for the specified stack frame.</p>
<h5>Arguments:</h5>
-
-<p>
-The argument to this intrinsic indicates which function to return the frame
-pointer for. Zero indicates the calling function, one indicates its caller,
-etc. The argument is <b>required</b> to be a constant integer value.
-</p>
+<p>The argument to this intrinsic indicates which function to return the frame
+ pointer for. Zero indicates the calling function, one indicates its caller,
+ etc. The argument is <b>required</b> to be a constant integer value.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
+ indicating the frame address of the specified call frame, or zero if it
+ cannot be identified. The value returned by this intrinsic is likely to be
+ incorrect or 0 for arguments other than zero, so it should only be used for
+ debugging purposes.</p>
-<p>
-The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
-the frame address of the specified call frame, or zero if it cannot be
-identified. The value returned by this intrinsic is likely to be incorrect or 0
-for arguments other than zero, so it should only be used for debugging purposes.
-</p>
+<p>Note that calling this intrinsic does not prevent function inlining or other
+ aggressive transformations, so the value returned may not be that of the
+ obvious source-language caller.</p>
-<p>
-Note that calling this intrinsic does not prevent function inlining or other
-aggressive transformations, so the value returned may not be that of the obvious
-source-language caller.
-</p>
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
-the function stack, for use with <a href="#int_stackrestore">
-<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
-features like scoped automatic variable sized arrays in C99.
-</p>
+<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
+ of the function stack, for use
+ with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
+ useful for implementing language features like scoped automatic variable
+ sized arrays in C99.</p>
<h5>Semantics:</h5>
-
-<p>
-This intrinsic returns a opaque pointer value that can be passed to <a
-href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
-<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
-<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
-state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
-practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
-that were allocated after the <tt>llvm.stacksave</tt> was executed.
-</p>
+<p>This intrinsic returns a opaque pointer value that can be passed
+ to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
+ an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
+ from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
+ to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
+ In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
+ stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
</div>
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
-the function stack to the state it was in when the corresponding <a
-href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
-useful for implementing language features like scoped automatic variable sized
-arrays in C99.
-</p>
+<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
+ the function stack to the state it was in when the
+ corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
+ executed. This is useful for implementing language features like scoped
+ automatic variable sized arrays in C99.</p>
<h5>Semantics:</h5>
-
-<p>
-See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
-</p>
+<p>See the description
+ for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
</pre>
<h5>Overview:</h5>
-
-
-<p>
-The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
-a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
-no
-effect on the behavior of the program but can change its performance
-characteristics.
-</p>
+<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
+ insert a prefetch instruction if supported; otherwise, it is a noop.
+ Prefetches have no effect on the behavior of the program but can change its
+ performance characteristics.</p>
<h5>Arguments:</h5>
-
-<p>
-<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
-determining if the fetch should be for a read (0) or write (1), and
-<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
-locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
-<tt>locality</tt> arguments must be constant integers.
-</p>
+<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
+ specifier determining if the fetch should be for a read (0) or write (1),
+ and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
+ locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
+ and <tt>locality</tt> arguments must be constant integers.</p>
<h5>Semantics:</h5>
-
-<p>
-This intrinsic does not modify the behavior of the program. In particular,
-prefetches cannot trap and do not produce a value. On targets that support this
-intrinsic, the prefetch can provide hints to the processor cache for better
-performance.
-</p>
+<p>This intrinsic does not modify the behavior of the program. In particular,
+ prefetches cannot trap and do not produce a value. On targets that support
+ this intrinsic, the prefetch can provide hints to the processor cache for
+ better performance.</p>
</div>
</pre>
<h5>Overview:</h5>
-
-
-<p>
-The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
-(PC) in a region of
-code to simulators and other tools. The method is target specific, but it is
-expected that the marker will use exported symbols to transmit the PC of the
-marker.
-The marker makes no guarantees that it will remain with any specific instruction
-after optimizations. It is possible that the presence of a marker will inhibit
-optimizations. The intended use is to be inserted after optimizations to allow
-correlations of simulation runs.
-</p>
+<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
+ Counter (PC) in a region of code to simulators and other tools. The method
+ is target specific, but it is expected that the marker will use exported
+ symbols to transmit the PC of the marker. The marker makes no guarantees
+ that it will remain with any specific instruction after optimizations. It is
+ possible that the presence of a marker will inhibit optimizations. The
+ intended use is to be inserted after optimizations to allow correlations of
+ simulation runs.</p>
<h5>Arguments:</h5>
-
-<p>
-<tt>id</tt> is a numerical id identifying the marker.
-</p>
+<p><tt>id</tt> is a numerical id identifying the marker.</p>
<h5>Semantics:</h5>
-
-<p>
-This intrinsic does not modify the behavior of the program. Backends that do not
-support this intrinisic may ignore it.
-</p>
+<p>This intrinsic does not modify the behavior of the program. Backends that do
+ not support this intrinisic may ignore it.</p>
</div>
</pre>
<h5>Overview:</h5>
-
-
-<p>
-The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
-counter register (or similar low latency, high accuracy clocks) on those targets
-that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
-As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
-should only be used for small timings.
-</p>
+<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
+ counter register (or similar low latency, high accuracy clocks) on those
+ targets that support it. On X86, it should map to RDTSC. On Alpha, it
+ should map to RPCC. As the backing counters overflow quickly (on the order
+ of 9 seconds on alpha), this should only be used for small timings.</p>
<h5>Semantics:</h5>
-
-<p>
-When directly supported, reading the cycle counter should not modify any memory.
-Implementations are allowed to either return a application specific value or a
-system wide value. On backends without support, this is lowered to a constant 0.
-</p>
+<p>When directly supported, reading the cycle counter should not modify any
+ memory. Implementations are allowed to either return a application specific
+ value or a system wide value. On backends without support, this is lowered
+ to a constant 0.</p>
</div>
</div>
<div class="doc_text">
-<p>
-LLVM provides intrinsics for a few important standard C library functions.
-These intrinsics allow source-language front-ends to pass information about the
-alignment of the pointer arguments to the code generator, providing opportunity
-for more efficient code generation.
-</p>
+
+<p>LLVM provides intrinsics for a few important standard C library functions.
+ These intrinsics allow source-language front-ends to pass information about
+ the alignment of the pointer arguments to the code generator, providing
+ opportunity for more efficient code generation.</p>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
-width. Not all targets support all bit widths however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+
<pre>
declare void @llvm.memcpy.i8(i8 * <dest>, i8 * <src>,
- i8 <len>, i32 <align>)
+ i8 <len>, i32 <align>)
declare void @llvm.memcpy.i16(i8 * <dest>, i8 * <src>,
i16 <len>, i32 <align>)
declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
</pre>
<h5>Overview:</h5>
+<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
+ source location to the destination location.</p>
-<p>
-The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
-location to the destination location.
-</p>
-
-<p>
-Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
-intrinsics do not return a value, and takes an extra alignment argument.
-</p>
+<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
+ intrinsics do not return a value, and takes an extra alignment argument.</p>
<h5>Arguments:</h5>
+<p>The first argument is a pointer to the destination, the second is a pointer
+ to the source. The third argument is an integer argument specifying the
+ number of bytes to copy, and the fourth argument is the alignment of the
+ source and destination locations.</p>
-<p>
-The first argument is a pointer to the destination, the second is a pointer to
-the source. The third argument is an integer argument
-specifying the number of bytes to copy, and the fourth argument is the alignment
-of the source and destination locations.
-</p>
-
-<p>
-If the call to this intrinisic has an alignment value that is not 0 or 1, then
-the caller guarantees that both the source and destination pointers are aligned
-to that boundary.
-</p>
+<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
+ then the caller guarantees that both the source and destination pointers are
+ aligned to that boundary.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
+ source location to the destination location, which are not allowed to
+ overlap. It copies "len" bytes of memory over. If the argument is known to
+ be aligned to some boundary, this can be specified as the fourth argument,
+ otherwise it should be set to 0 or 1.</p>
-<p>
-The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
-location to the destination location, which are not allowed to overlap. It
-copies "len" bytes of memory over. If the argument is known to be aligned to
-some boundary, this can be specified as the fourth argument, otherwise it should
-be set to 0 or 1.
-</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
-width. Not all targets support all bit widths however.</p>
+ width. Not all targets support all bit widths however.</p>
+
<pre>
declare void @llvm.memmove.i8(i8 * <dest>, i8 * <src>,
- i8 <len>, i32 <align>)
+ i8 <len>, i32 <align>)
declare void @llvm.memmove.i16(i8 * <dest>, i8 * <src>,
i16 <len>, i32 <align>)
declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
</pre>
<h5>Overview:</h5>
+<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
+ source location to the destination location. It is similar to the
+ '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
+ overlap.</p>
-<p>
-The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
-location to the destination location. It is similar to the
-'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
-</p>
-
-<p>
-Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
-intrinsics do not return a value, and takes an extra alignment argument.
-</p>
+<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
+ intrinsics do not return a value, and takes an extra alignment argument.</p>
<h5>Arguments:</h5>
+<p>The first argument is a pointer to the destination, the second is a pointer
+ to the source. The third argument is an integer argument specifying the
+ number of bytes to copy, and the fourth argument is the alignment of the
+ source and destination locations.</p>
-<p>
-The first argument is a pointer to the destination, the second is a pointer to
-the source. The third argument is an integer argument
-specifying the number of bytes to copy, and the fourth argument is the alignment
-of the source and destination locations.
-</p>
-
-<p>
-If the call to this intrinisic has an alignment value that is not 0 or 1, then
-the caller guarantees that the source and destination pointers are aligned to
-that boundary.
-</p>
+<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
+ then the caller guarantees that the source and destination pointers are
+ aligned to that boundary.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
+ source location to the destination location, which may overlap. It copies
+ "len" bytes of memory over. If the argument is known to be aligned to some
+ boundary, this can be specified as the fourth argument, otherwise it should
+ be set to 0 or 1.</p>
-<p>
-The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
-location to the destination location, which may overlap. It
-copies "len" bytes of memory over. If the argument is known to be aligned to
-some boundary, this can be specified as the fourth argument, otherwise it should
-be set to 0 or 1.
-</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
-width. Not all targets support all bit widths however.</p>
+ width. Not all targets support all bit widths however.</p>
+
<pre>
declare void @llvm.memset.i8(i8 * <dest>, i8 <val>,
- i8 <len>, i32 <align>)
+ i8 <len>, i32 <align>)
declare void @llvm.memset.i16(i8 * <dest>, i8 <val>,
i16 <len>, i32 <align>)
declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
</pre>
<h5>Overview:</h5>
+<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
+ particular byte value.</p>
-<p>
-The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
-byte value.
-</p>
-
-<p>
-Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
-does not return a value, and takes an extra alignment argument.
-</p>
+<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
+ intrinsic does not return a value, and takes an extra alignment argument.</p>
<h5>Arguments:</h5>
+<p>The first argument is a pointer to the destination to fill, the second is the
+ byte value to fill it with, the third argument is an integer argument
+ specifying the number of bytes to fill, and the fourth argument is the known
+ alignment of destination location.</p>
-<p>
-The first argument is a pointer to the destination to fill, the second is the
-byte value to fill it with, the third argument is an integer
-argument specifying the number of bytes to fill, and the fourth argument is the
-known alignment of destination location.
-</p>
-
-<p>
-If the call to this intrinisic has an alignment value that is not 0 or 1, then
-the caller guarantees that the destination pointer is aligned to that boundary.
-</p>
+<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
+ then the caller guarantees that the destination pointer is aligned to that
+ boundary.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
+ at the destination location. If the argument is known to be aligned to some
+ boundary, this can be specified as the fourth argument, otherwise it should
+ be set to 0 or 1.</p>
-<p>
-The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
-the
-destination location. If the argument is known to be aligned to some boundary,
-this can be specified as the fourth argument, otherwise it should be set to 0 or
-1.
-</p>
</div>
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
-floating point or vector of floating point type. Not all targets support all
-types however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
<pre>
declare float @llvm.sqrt.f32(float %Val)
declare double @llvm.sqrt.f64(double %Val)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
-returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
-<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
-negative numbers other than -0.0 (which allows for better optimization, because
-there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
-defined to return -0.0 like IEEE sqrt.
-</p>
+<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
+ returning the same value as the libm '<tt>sqrt</tt>' functions would.
+ Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
+ behavior for negative numbers other than -0.0 (which allows for better
+ optimization, because there is no need to worry about errno being
+ set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
<h5>Arguments:</h5>
-
-<p>
-The argument and return value are floating point numbers of the same type.
-</p>
+<p>The argument and return value are floating point numbers of the same
+ type.</p>
<h5>Semantics:</h5>
+<p>This function returns the sqrt of the specified operand if it is a
+ nonnegative floating point number.</p>
-<p>
-This function returns the sqrt of the specified operand if it is a nonnegative
-floating point number.
-</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
-floating point or vector of floating point type. Not all targets support all
-types however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
<pre>
declare float @llvm.powi.f32(float %Val, i32 %power)
declare double @llvm.powi.f64(double %Val, i32 %power)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
-specified (positive or negative) power. The order of evaluation of
-multiplications is not defined. When a vector of floating point type is
-used, the second argument remains a scalar integer value.
-</p>
+<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
+ specified (positive or negative) power. The order of evaluation of
+ multiplications is not defined. When a vector of floating point type is
+ used, the second argument remains a scalar integer value.</p>
<h5>Arguments:</h5>
-
-<p>
-The second argument is an integer power, and the first is a value to raise to
-that power.
-</p>
+<p>The second argument is an integer power, and the first is a value to raise to
+ that power.</p>
<h5>Semantics:</h5>
+<p>This function returns the first value raised to the second power with an
+ unspecified sequence of rounding operations.</p>
-<p>
-This function returns the first value raised to the second power with an
-unspecified sequence of rounding operations.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
-floating point or vector of floating point type. Not all targets support all
-types however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
<pre>
declare float @llvm.sin.f32(float %Val)
declare double @llvm.sin.f64(double %Val)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
-</p>
+<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
<h5>Arguments:</h5>
-
-<p>
-The argument and return value are floating point numbers of the same type.
-</p>
+<p>The argument and return value are floating point numbers of the same
+ type.</p>
<h5>Semantics:</h5>
+<p>This function returns the sine of the specified operand, returning the same
+ values as the libm <tt>sin</tt> functions would, and handles error conditions
+ in the same way.</p>
-<p>
-This function returns the sine of the specified operand, returning the
-same values as the libm <tt>sin</tt> functions would, and handles error
-conditions in the same way.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
-floating point or vector of floating point type. Not all targets support all
-types however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
<pre>
declare float @llvm.cos.f32(float %Val)
declare double @llvm.cos.f64(double %Val)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
-</p>
+<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
<h5>Arguments:</h5>
-
-<p>
-The argument and return value are floating point numbers of the same type.
-</p>
+<p>The argument and return value are floating point numbers of the same
+ type.</p>
<h5>Semantics:</h5>
+<p>This function returns the cosine of the specified operand, returning the same
+ values as the libm <tt>cos</tt> functions would, and handles error conditions
+ in the same way.</p>
-<p>
-This function returns the cosine of the specified operand, returning the
-same values as the libm <tt>cos</tt> functions would, and handles error
-conditions in the same way.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
-floating point or vector of floating point type. Not all targets support all
-types however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
<pre>
declare float @llvm.pow.f32(float %Val, float %Power)
declare double @llvm.pow.f64(double %Val, double %Power)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
-specified (positive or negative) power.
-</p>
+<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
+ specified (positive or negative) power.</p>
<h5>Arguments:</h5>
-
-<p>
-The second argument is a floating point power, and the first is a value to
-raise to that power.
-</p>
+<p>The second argument is a floating point power, and the first is a value to
+ raise to that power.</p>
<h5>Semantics:</h5>
+<p>This function returns the first value raised to the second power, returning
+ the same values as the libm <tt>pow</tt> functions would, and handles error
+ conditions in the same way.</p>
-<p>
-This function returns the first value raised to the second power,
-returning the
-same values as the libm <tt>pow</tt> functions would, and handles error
-conditions in the same way.</p>
</div>
-
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="int_manip">Bit Manipulation Intrinsics</a>
</div>
<div class="doc_text">
-<p>
-LLVM provides intrinsics for a few important bit manipulation operations.
-These allow efficient code generation for some algorithms.
-</p>
+
+<p>LLVM provides intrinsics for a few important bit manipulation operations.
+ These allow efficient code generation for some algorithms.</p>
</div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic function. You can use bswap on any integer
-type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
+ type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
+
<pre>
declare i16 @llvm.bswap.i16(i16 <id>)
declare i32 @llvm.bswap.i32(i32 <id>)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
-values with an even number of bytes (positive multiple of 16 bits). These are
-useful for performing operations on data that is not in the target's native
-byte order.
-</p>
+<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
+ values with an even number of bytes (positive multiple of 16 bits). These
+ are useful for performing operations on data that is not in the target's
+ native byte order.</p>
<h5>Semantics:</h5>
-
-<p>
-The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
-and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
-intrinsic returns an i32 value that has the four bytes of the input i32
-swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
-i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
-<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
-additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
-</p>
+<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
+ and low byte of the input i16 swapped. Similarly,
+ the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
+ bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
+ 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
+ The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
+ extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
+ more, respectively).</p>
</div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
-width. Not all targets support all bit widths however.</p>
+ width. Not all targets support all bit widths however.</p>
+
<pre>
declare i8 @llvm.ctpop.i8(i8 <src>)
declare i16 @llvm.ctpop.i16(i16 <src>)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
-value.
-</p>
+<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
+ in a value.</p>
<h5>Arguments:</h5>
-
-<p>
-The only argument is the value to be counted. The argument may be of any
-integer type. The return type must match the argument type.
-</p>
+<p>The only argument is the value to be counted. The argument may be of any
+ integer type. The return type must match the argument type.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
-<p>
-The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
-</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
-integer bit width. Not all targets support all bit widths however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+
<pre>
declare i8 @llvm.ctlz.i8 (i8 <src>)
declare i16 @llvm.ctlz.i16(i16 <src>)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
-leading zeros in a variable.
-</p>
+<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
+ leading zeros in a variable.</p>
<h5>Arguments:</h5>
-
-<p>
-The only argument is the value to be counted. The argument may be of any
-integer type. The return type must match the argument type.
-</p>
+<p>The only argument is the value to be counted. The argument may be of any
+ integer type. The return type must match the argument type.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
+ zeros in a variable. If the src == 0 then the result is the size in bits of
+ the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
-<p>
-The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
-in a variable. If the src == 0 then the result is the size in bits of the type
-of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
-</p>
</div>
-
-
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
-integer bit width. Not all targets support all bit widths however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+
<pre>
declare i8 @llvm.cttz.i8 (i8 <src>)
declare i16 @llvm.cttz.i16(i16 <src>)
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
-trailing zeros.
-</p>
-
-<h5>Arguments:</h5>
-
-<p>
-The only argument is the value to be counted. The argument may be of any
-integer type. The return type must match the argument type.
-</p>
-
-<h5>Semantics:</h5>
-
-<p>
-The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
-in a variable. If the src == 0 then the result is the size in bits of the type
-of src. For example, <tt>llvm.cttz(2) = 1</tt>.
-</p>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
-</div>
-
-<div class="doc_text">
-
-<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
-on any integer bit width.</p>
-<pre>
- declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
- declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
-</pre>
-
-<h5>Overview:</h5>
-<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
-range of bits from an integer value and returns them in the same bit width as
-the original value.</p>
-
-<h5>Arguments:</h5>
-<p>The first argument, <tt>%val</tt> and the result may be integer types of
-any bit width but they must have the same bit width. The second and third
-arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
-
-<h5>Semantics:</h5>
-<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
-of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
-<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
-operates in forward mode.</p>
-<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
-right by <tt>%loBit</tt> bits and then ANDing it with a mask with
-only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
-<ol>
- <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
- by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
- <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
- to determine the number of bits to retain.</li>
- <li>A mask of the retained bits is created by shifting a -1 value.</li>
- <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
-</ol>
-<p>In reverse mode, a similar computation is made except that the bits are
-returned in the reverse order. So, for example, if <tt>X</tt> has the value
-<tt>i16 0x0ACF (101011001111)</tt> and we apply
-<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
-<tt>i16 0x0026 (000000100110)</tt>.</p>
-</div>
-
-<div class="doc_subsubsection">
- <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
-</div>
-
-<div class="doc_text">
-
-<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
-on any integer bit width.</p>
-<pre>
- declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
- declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
-</pre>
-
-<h5>Overview:</h5>
-<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
-of bits in an integer value with another integer value. It returns the integer
-with the replaced bits.</p>
+<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
+ trailing zeros.</p>
<h5>Arguments:</h5>
-<p>The first argument, <tt>%val</tt>, and the result may be integer types of
-any bit width, but they must have the same bit width. <tt>%val</tt> is the value
-whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
-integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
-type since they specify only a bit index.</p>
+<p>The only argument is the value to be counted. The argument may be of any
+ integer type. The return type must match the argument type.</p>
<h5>Semantics:</h5>
-<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
-of operation: forwards and reverse. If <tt>%lo</tt> is greater than
-<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
-operates in forward mode.</p>
-
-<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
-truncating it down to the size of the replacement area or zero extending it
-up to that size.</p>
-
-<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
-are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
-in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
-to the <tt>%hi</tt>th bit.</p>
-
-<p>In reverse mode, a similar computation is made except that the bits are
-reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
-<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
-
-<h5>Examples:</h5>
-
-<pre>
- llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
- llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
- llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F
- llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
- llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
-</pre>
+<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
+ zeros in a variable. If the src == 0 then the result is the size in bits of
+ the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
</div>
</div>
<div class="doc_text">
-<p>
-LLVM provides intrinsics for some arithmetic with overflow operations.
-</p>
+
+<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-
<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
-on any integer bit width.</p>
+ on any integer bit width.</p>
<pre>
declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
-a signed addition of the two arguments, and indicate whether an overflow
-occurred during the signed summation.</p>
+ a signed addition of the two arguments, and indicate whether an overflow
+ occurred during the signed summation.</p>
<h5>Arguments:</h5>
-
<p>The arguments (%a and %b) and the first element of the result structure may
-be of integer types of any bit width, but they must have the same bit width. The
-second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
-and <tt>%b</tt> are the two values that will undergo signed addition.</p>
+ be of integer types of any bit width, but they must have the same bit
+ width. The second element of the result structure must be of
+ type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
+ undergo signed addition.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
-a signed addition of the two variables. They return a structure — the
-first element of which is the signed summation, and the second element of which
-is a bit specifying if the signed summation resulted in an overflow.</p>
+ a signed addition of the two variables. They return a structure — the
+ first element of which is the signed summation, and the second element of
+ which is a bit specifying if the signed summation resulted in an
+ overflow.</p>
<h5>Examples:</h5>
<pre>
<div class="doc_text">
<h5>Syntax:</h5>
-
<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
-on any integer bit width.</p>
+ on any integer bit width.</p>
<pre>
declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
-an unsigned addition of the two arguments, and indicate whether a carry occurred
-during the unsigned summation.</p>
+ an unsigned addition of the two arguments, and indicate whether a carry
+ occurred during the unsigned summation.</p>
<h5>Arguments:</h5>
-
<p>The arguments (%a and %b) and the first element of the result structure may
-be of integer types of any bit width, but they must have the same bit width. The
-second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
-and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
+ be of integer types of any bit width, but they must have the same bit
+ width. The second element of the result structure must be of
+ type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
+ undergo unsigned addition.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
-an unsigned addition of the two arguments. They return a structure — the
-first element of which is the sum, and the second element of which is a bit
-specifying if the unsigned summation resulted in a carry.</p>
+ an unsigned addition of the two arguments. They return a structure —
+ the first element of which is the sum, and the second element of which is a
+ bit specifying if the unsigned summation resulted in a carry.</p>
<h5>Examples:</h5>
<pre>
<div class="doc_text">
<h5>Syntax:</h5>
-
<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
-on any integer bit width.</p>
+ on any integer bit width.</p>
<pre>
declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
-a signed subtraction of the two arguments, and indicate whether an overflow
-occurred during the signed subtraction.</p>
+ a signed subtraction of the two arguments, and indicate whether an overflow
+ occurred during the signed subtraction.</p>
<h5>Arguments:</h5>
-
<p>The arguments (%a and %b) and the first element of the result structure may
-be of integer types of any bit width, but they must have the same bit width. The
-second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
-and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
+ be of integer types of any bit width, but they must have the same bit
+ width. The second element of the result structure must be of
+ type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
+ undergo signed subtraction.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
-a signed subtraction of the two arguments. They return a structure — the
-first element of which is the subtraction, and the second element of which is a bit
-specifying if the signed subtraction resulted in an overflow.</p>
+ a signed subtraction of the two arguments. They return a structure —
+ the first element of which is the subtraction, and the second element of
+ which is a bit specifying if the signed subtraction resulted in an
+ overflow.</p>
<h5>Examples:</h5>
<pre>
<div class="doc_text">
<h5>Syntax:</h5>
-
<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
-on any integer bit width.</p>
+ on any integer bit width.</p>
<pre>
declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
-an unsigned subtraction of the two arguments, and indicate whether an overflow
-occurred during the unsigned subtraction.</p>
+ an unsigned subtraction of the two arguments, and indicate whether an
+ overflow occurred during the unsigned subtraction.</p>
<h5>Arguments:</h5>
-
<p>The arguments (%a and %b) and the first element of the result structure may
-be of integer types of any bit width, but they must have the same bit width. The
-second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
-and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
+ be of integer types of any bit width, but they must have the same bit
+ width. The second element of the result structure must be of
+ type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
+ undergo unsigned subtraction.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
-an unsigned subtraction of the two arguments. They return a structure — the
-first element of which is the subtraction, and the second element of which is a bit
-specifying if the unsigned subtraction resulted in an overflow.</p>
+ an unsigned subtraction of the two arguments. They return a structure —
+ the first element of which is the subtraction, and the second element of
+ which is a bit specifying if the unsigned subtraction resulted in an
+ overflow.</p>
<h5>Examples:</h5>
<pre>
<div class="doc_text">
<h5>Syntax:</h5>
-
<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
-on any integer bit width.</p>
+ on any integer bit width.</p>
<pre>
declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
<h5>Overview:</h5>
<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
-a signed multiplication of the two arguments, and indicate whether an overflow
-occurred during the signed multiplication.</p>
+ a signed multiplication of the two arguments, and indicate whether an
+ overflow occurred during the signed multiplication.</p>
<h5>Arguments:</h5>
-
<p>The arguments (%a and %b) and the first element of the result structure may
-be of integer types of any bit width, but they must have the same bit width. The
-second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
-and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
+ be of integer types of any bit width, but they must have the same bit
+ width. The second element of the result structure must be of
+ type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
+ undergo signed multiplication.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
-a signed multiplication of the two arguments. They return a structure —
-the first element of which is the multiplication, and the second element of
-which is a bit specifying if the signed multiplication resulted in an
-overflow.</p>
+ a signed multiplication of the two arguments. They return a structure —
+ the first element of which is the multiplication, and the second element of
+ which is a bit specifying if the signed multiplication resulted in an
+ overflow.</p>
<h5>Examples:</h5>
<pre>
<div class="doc_text">
<h5>Syntax:</h5>
-
<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
-on any integer bit width.</p>
+ on any integer bit width.</p>
<pre>
declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
</pre>
<h5>Overview:</h5>
-
<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
-a unsigned multiplication of the two arguments, and indicate whether an overflow
-occurred during the unsigned multiplication.</p>
+ a unsigned multiplication of the two arguments, and indicate whether an
+ overflow occurred during the unsigned multiplication.</p>
<h5>Arguments:</h5>
-
<p>The arguments (%a and %b) and the first element of the result structure may
-be of integer types of any bit width, but they must have the same bit width. The
-second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
-and <tt>%b</tt> are the two values that will undergo unsigned
-multiplication.</p>
+ be of integer types of any bit width, but they must have the same bit
+ width. The second element of the result structure must be of
+ type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
+ undergo unsigned multiplication.</p>
<h5>Semantics:</h5>
-
<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
-an unsigned multiplication of the two arguments. They return a structure —
-the first element of which is the multiplication, and the second element of
-which is a bit specifying if the unsigned multiplication resulted in an
-overflow.</p>
+ an unsigned multiplication of the two arguments. They return a structure
+ — the first element of which is the multiplication, and the second
+ element of which is a bit specifying if the unsigned multiplication resulted
+ in an overflow.</p>
<h5>Examples:</h5>
<pre>
</div>
<div class="doc_text">
-<p>
-The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
-are described in the <a
-href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
-Debugging</a> document.
-</p>
-</div>
+<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
+ prefix), are described in
+ the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
+ Level Debugging</a> document.</p>
+
+</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
</div>
<div class="doc_text">
-<p> The LLVM exception handling intrinsics (which all start with
-<tt>llvm.eh.</tt> prefix), are described in the <a
-href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
-Handling</a> document. </p>
+
+<p>The LLVM exception handling intrinsics (which all start with
+ <tt>llvm.eh.</tt> prefix), are described in
+ the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
+ Handling</a> document.</p>
+
</div>
<!-- ======================================================================= -->
</div>
<div class="doc_text">
-<p>
- This intrinsic makes it possible to excise one parameter, marked with
- the <tt>nest</tt> attribute, from a function. The result is a callable
- function pointer lacking the nest parameter - the caller does not need
- to provide a value for it. Instead, the value to use is stored in
- advance in a "trampoline", a block of memory usually allocated
- on the stack, which also contains code to splice the nest value into the
- argument list. This is used to implement the GCC nested function address
- extension.
-</p>
-<p>
- For example, if the function is
- <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
- pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
+
+<p>This intrinsic makes it possible to excise one parameter, marked with
+ the <tt>nest</tt> attribute, from a function. The result is a callable
+ function pointer lacking the nest parameter - the caller does not need to
+ provide a value for it. Instead, the value to use is stored in advance in a
+ "trampoline", a block of memory usually allocated on the stack, which also
+ contains code to splice the nest value into the argument list. This is used
+ to implement the GCC nested function address extension.</p>
+
+<p>For example, if the function is
+ <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
+ pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
+ follows:</p>
+
+<div class="doc_code">
<pre>
%tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
%tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
%p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
%fp = bitcast i8* %p to i32 (i32, i32)*
</pre>
- <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
- to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
+</div>
+
+<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
+ to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
<pre>
-declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
+ declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
</pre>
+
<h5>Overview:</h5>
-<p>
- This fills the memory pointed to by <tt>tramp</tt> with code
- and returns a function pointer suitable for executing it.
-</p>
+<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
+ function pointer suitable for executing it.</p>
+
<h5>Arguments:</h5>
-<p>
- The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
- pointers. The <tt>tramp</tt> argument must point to a sufficiently large
- and sufficiently aligned block of memory; this memory is written to by the
- intrinsic. Note that the size and the alignment are target-specific - LLVM
- currently provides no portable way of determining them, so a front-end that
- generates this intrinsic needs to have some target-specific knowledge.
- The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
-</p>
+<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
+ pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
+ sufficiently aligned block of memory; this memory is written to by the
+ intrinsic. Note that the size and the alignment are target-specific - LLVM
+ currently provides no portable way of determining them, so a front-end that
+ generates this intrinsic needs to have some target-specific knowledge.
+ The <tt>func</tt> argument must hold a function bitcast to
+ an <tt>i8*</tt>.</p>
+
<h5>Semantics:</h5>
-<p>
- The block of memory pointed to by <tt>tramp</tt> is filled with target
- dependent code, turning it into a function. A pointer to this function is
- returned, but needs to be bitcast to an
- <a href="#int_trampoline">appropriate function pointer type</a>
- before being called. The new function's signature is the same as that of
- <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
- removed. At most one such <tt>nest</tt> argument is allowed, and it must be
- of pointer type. Calling the new function is equivalent to calling
- <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
- missing <tt>nest</tt> argument. If, after calling
- <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
- modified, then the effect of any later call to the returned function pointer is
- undefined.
-</p>
+<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
+ dependent code, turning it into a function. A pointer to this function is
+ returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
+ function pointer type</a> before being called. The new function's signature
+ is the same as that of <tt>func</tt> with any arguments marked with
+ the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
+ is allowed, and it must be of pointer type. Calling the new function is
+ equivalent to calling <tt>func</tt> with the same argument list, but
+ with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
+ calling <tt>llvm.init.trampoline</tt>, the memory pointed to
+ by <tt>tramp</tt> is modified, then the effect of any later call to the
+ returned function pointer is undefined.</p>
+
</div>
<!-- ======================================================================= -->
</div>
<div class="doc_text">
-<p>
- These intrinsic functions expand the "universal IR" of LLVM to represent
- hardware constructs for atomic operations and memory synchronization. This
- provides an interface to the hardware, not an interface to the programmer. It
- is aimed at a low enough level to allow any programming models or APIs
- (Application Programming Interfaces) which
- need atomic behaviors to map cleanly onto it. It is also modeled primarily on
- hardware behavior. Just as hardware provides a "universal IR" for source
- languages, it also provides a starting point for developing a "universal"
- atomic operation and synchronization IR.
-</p>
-<p>
- These do <em>not</em> form an API such as high-level threading libraries,
- software transaction memory systems, atomic primitives, and intrinsic
- functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
- application libraries. The hardware interface provided by LLVM should allow
- a clean implementation of all of these APIs and parallel programming models.
- No one model or paradigm should be selected above others unless the hardware
- itself ubiquitously does so.
-</p>
+<p>These intrinsic functions expand the "universal IR" of LLVM to represent
+ hardware constructs for atomic operations and memory synchronization. This
+ provides an interface to the hardware, not an interface to the programmer. It
+ is aimed at a low enough level to allow any programming models or APIs
+ (Application Programming Interfaces) which need atomic behaviors to map
+ cleanly onto it. It is also modeled primarily on hardware behavior. Just as
+ hardware provides a "universal IR" for source languages, it also provides a
+ starting point for developing a "universal" atomic operation and
+ synchronization IR.</p>
+
+<p>These do <em>not</em> form an API such as high-level threading libraries,
+ software transaction memory systems, atomic primitives, and intrinsic
+ functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
+ application libraries. The hardware interface provided by LLVM should allow
+ a clean implementation of all of these APIs and parallel programming models.
+ No one model or paradigm should be selected above others unless the hardware
+ itself ubiquitously does so.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
<pre>
-declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>,
-i1 <device> )
-
+ declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>, i1 <device> )
</pre>
+
<h5>Overview:</h5>
-<p>
- The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
- specific pairs of memory access types.
-</p>
+<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
+ specific pairs of memory access types.</p>
+
<h5>Arguments:</h5>
-<p>
- The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
- The first four arguments enables a specific barrier as listed below. The fith
- argument specifies that the barrier applies to io or device or uncached memory.
+<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
+ The first four arguments enables a specific barrier as listed below. The
+ fith argument specifies that the barrier applies to io or device or uncached
+ memory.</p>
+
+<ul>
+ <li><tt>ll</tt>: load-load barrier</li>
+ <li><tt>ls</tt>: load-store barrier</li>
+ <li><tt>sl</tt>: store-load barrier</li>
+ <li><tt>ss</tt>: store-store barrier</li>
+ <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
+</ul>
-</p>
- <ul>
- <li><tt>ll</tt>: load-load barrier</li>
- <li><tt>ls</tt>: load-store barrier</li>
- <li><tt>sl</tt>: store-load barrier</li>
- <li><tt>ss</tt>: store-store barrier</li>
- <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
- </ul>
<h5>Semantics:</h5>
-<p>
- This intrinsic causes the system to enforce some ordering constraints upon
- the loads and stores of the program. This barrier does not indicate
- <em>when</em> any events will occur, it only enforces an <em>order</em> in
- which they occur. For any of the specified pairs of load and store operations
- (f.ex. load-load, or store-load), all of the first operations preceding the
- barrier will complete before any of the second operations succeeding the
- barrier begin. Specifically the semantics for each pairing is as follows:
-</p>
- <ul>
- <li><tt>ll</tt>: All loads before the barrier must complete before any load
- after the barrier begins.</li>
-
- <li><tt>ls</tt>: All loads before the barrier must complete before any
- store after the barrier begins.</li>
- <li><tt>ss</tt>: All stores before the barrier must complete before any
- store after the barrier begins.</li>
- <li><tt>sl</tt>: All stores before the barrier must complete before any
- load after the barrier begins.</li>
- </ul>
-<p>
- These semantics are applied with a logical "and" behavior when more than one
- is enabled in a single memory barrier intrinsic.
-</p>
-<p>
- Backends may implement stronger barriers than those requested when they do not
- support as fine grained a barrier as requested. Some architectures do not
- need all types of barriers and on such architectures, these become noops.
-</p>
+<p>This intrinsic causes the system to enforce some ordering constraints upon
+ the loads and stores of the program. This barrier does not
+ indicate <em>when</em> any events will occur, it only enforces
+ an <em>order</em> in which they occur. For any of the specified pairs of load
+ and store operations (f.ex. load-load, or store-load), all of the first
+ operations preceding the barrier will complete before any of the second
+ operations succeeding the barrier begin. Specifically the semantics for each
+ pairing is as follows:</p>
+
+<ul>
+ <li><tt>ll</tt>: All loads before the barrier must complete before any load
+ after the barrier begins.</li>
+ <li><tt>ls</tt>: All loads before the barrier must complete before any
+ store after the barrier begins.</li>
+ <li><tt>ss</tt>: All stores before the barrier must complete before any
+ store after the barrier begins.</li>
+ <li><tt>sl</tt>: All stores before the barrier must complete before any
+ load after the barrier begins.</li>
+</ul>
+
+<p>These semantics are applied with a logical "and" behavior when more than one
+ is enabled in a single memory barrier intrinsic.</p>
+
+<p>Backends may implement stronger barriers than those requested when they do
+ not support as fine grained a barrier as requested. Some architectures do
+ not need all types of barriers and on such architectures, these become
+ noops.</p>
+
<h5>Example:</h5>
<pre>
-%ptr = malloc i32
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
store i32 4, %ptr
%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
<i>; guarantee the above finishes</i>
store i32 8, %ptr <i>; before this begins</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<p>
- This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
- any integer bit width and for different address spaces. Not all targets
- support all bit widths however.</p>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
+ any integer bit width and for different address spaces. Not all targets
+ support all bit widths however.</p>
<pre>
-declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
-declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
-declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
-declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* <ptr>, i64 <cmp>, i64 <val> )
-
+ declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
+ declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
+ declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
+ declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* <ptr>, i64 <cmp>, i64 <val> )
</pre>
+
<h5>Overview:</h5>
-<p>
- This loads a value in memory and compares it to a given value. If they are
- equal, it stores a new value into the memory.
-</p>
+<p>This loads a value in memory and compares it to a given value. If they are
+ equal, it stores a new value into the memory.</p>
+
<h5>Arguments:</h5>
-<p>
- The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
- well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
- same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
- this integer type. While any bit width integer may be used, targets may only
- lower representations they support in hardware.
+<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
+ as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
+ same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
+ this integer type. While any bit width integer may be used, targets may only
+ lower representations they support in hardware.</p>
-</p>
<h5>Semantics:</h5>
-<p>
- This entire intrinsic must be executed atomically. It first loads the value
- in memory pointed to by <tt>ptr</tt> and compares it with the value
- <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
- loaded value is yielded in all cases. This provides the equivalent of an
- atomic compare-and-swap operation within the SSA framework.
-</p>
-<h5>Examples:</h5>
+<p>This entire intrinsic must be executed atomically. It first loads the value
+ in memory pointed to by <tt>ptr</tt> and compares it with the
+ value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
+ memory. The loaded value is yielded in all cases. This provides the
+ equivalent of an atomic compare-and-swap operation within the SSA
+ framework.</p>
+<h5>Examples:</h5>
<pre>
-%ptr = malloc i32
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
store i32 4, %ptr
%val1 = add i32 4, 4
%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>
- This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
- integer bit width. Not all targets support all bit widths however.</p>
-<pre>
-declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
-declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
-declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
-declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
+<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+<pre>
+ declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
+ declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
+ declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
+ declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
</pre>
+
<h5>Overview:</h5>
-<p>
- This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
- the value from memory. It then stores the value in <tt>val</tt> in the memory
- at <tt>ptr</tt>.
-</p>
+<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
+ the value from memory. It then stores the value in <tt>val</tt> in the memory
+ at <tt>ptr</tt>.</p>
+
<h5>Arguments:</h5>
+<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
+ the <tt>val</tt> argument and the result must be integers of the same bit
+ width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
+ integer type. The targets may only lower integer representations they
+ support.</p>
-<p>
- The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
- <tt>val</tt> argument and the result must be integers of the same bit width.
- The first argument, <tt>ptr</tt>, must be a pointer to a value of this
- integer type. The targets may only lower integer representations they
- support.
-</p>
<h5>Semantics:</h5>
-<p>
- This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
- stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
- equivalent of an atomic swap operation within the SSA framework.
+<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
+ stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
+ equivalent of an atomic swap operation within the SSA framework.</p>
-</p>
<h5>Examples:</h5>
<pre>
-%ptr = malloc i32
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
store i32 4, %ptr
%val1 = add i32 4, 4
%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<p>
- This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
- integer bit width. Not all targets support all bit widths however.</p>
-<pre>
-declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
+<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
+ any integer bit width. Not all targets support all bit widths however.</p>
+<pre>
+ declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
</pre>
+
<h5>Overview:</h5>
-<p>
- This intrinsic adds <tt>delta</tt> to the value stored in memory at
- <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
-</p>
+<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
+ at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
+
<h5>Arguments:</h5>
-<p>
+<p>The intrinsic takes two arguments, the first a pointer to an integer value
+ and the second an integer value. The result is also an integer value. These
+ integer types can have any bit width, but they must all have the same bit
+ width. The targets may only lower integer representations they support.</p>
- The intrinsic takes two arguments, the first a pointer to an integer value
- and the second an integer value. The result is also an integer value. These
- integer types can have any bit width, but they must all have the same bit
- width. The targets may only lower integer representations they support.
-</p>
<h5>Semantics:</h5>
-<p>
- This intrinsic does a series of operations atomically. It first loads the
- value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
- to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
-</p>
+<p>This intrinsic does a series of operations atomically. It first loads the
+ value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
+ to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
<h5>Examples:</h5>
<pre>
-%ptr = malloc i32
- store i32 4, %ptr
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
+ store i32 4, %ptr
%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
<i>; yields {i32}:result1 = 4</i>
%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
<i>; yields {i32}:result3 = 10</i>
%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<p>
- This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
- any integer bit width and for different address spaces. Not all targets
- support all bit widths however.</p>
-<pre>
-declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* <ptr>, i64 <delta> )
+<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
+ any integer bit width and for different address spaces. Not all targets
+ support all bit widths however.</p>
+<pre>
+ declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* <ptr>, i64 <delta> )
</pre>
+
<h5>Overview:</h5>
-<p>
- This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
- <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
-</p>
+<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
+ <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
+
<h5>Arguments:</h5>
-<p>
+<p>The intrinsic takes two arguments, the first a pointer to an integer value
+ and the second an integer value. The result is also an integer value. These
+ integer types can have any bit width, but they must all have the same bit
+ width. The targets may only lower integer representations they support.</p>
- The intrinsic takes two arguments, the first a pointer to an integer value
- and the second an integer value. The result is also an integer value. These
- integer types can have any bit width, but they must all have the same bit
- width. The targets may only lower integer representations they support.
-</p>
<h5>Semantics:</h5>
-<p>
- This intrinsic does a series of operations atomically. It first loads the
- value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
- result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
-</p>
+<p>This intrinsic does a series of operations atomically. It first loads the
+ value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
+ result to <tt>ptr</tt>. It yields the original value stored
+ at <tt>ptr</tt>.</p>
<h5>Examples:</h5>
<pre>
-%ptr = malloc i32
- store i32 8, %ptr
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
+ store i32 8, %ptr
%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
<i>; yields {i32}:result1 = 8</i>
%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
<i>; yields {i32}:result3 = 2</i>
%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
</pre>
+
</div>
<!-- _______________________________________________________________________ -->
<a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
<a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
<a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
-
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<p>
- These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
- <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
- <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
- address spaces. Not all targets support all bit widths however.</p>
-<pre>
-declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.and.i64.p0i64( i64* <ptr>, i64 <delta> )
+<p>These are overloaded intrinsics. You can
+ use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
+ <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
+ bit width and for different address spaces. Not all targets support all bit
+ widths however.</p>
+<pre>
+ declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.and.i64.p0i64( i64* <ptr>, i64 <delta> )
</pre>
<pre>
-declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.or.i64.p0i64( i64* <ptr>, i64 <delta> )
-
+ declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.or.i64.p0i64( i64* <ptr>, i64 <delta> )
</pre>
<pre>
-declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* <ptr>, i64 <delta> )
-
+ declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* <ptr>, i64 <delta> )
</pre>
<pre>
-declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* <ptr>, i64 <delta> )
-
+ declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* <ptr>, i64 <delta> )
</pre>
+
<h5>Overview:</h5>
-<p>
- These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
- the value stored in memory at <tt>ptr</tt>. It yields the original value
- at <tt>ptr</tt>.
-</p>
+<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
+ the value stored in memory at <tt>ptr</tt>. It yields the original value
+ at <tt>ptr</tt>.</p>
+
<h5>Arguments:</h5>
-<p>
+<p>These intrinsics take two arguments, the first a pointer to an integer value
+ and the second an integer value. The result is also an integer value. These
+ integer types can have any bit width, but they must all have the same bit
+ width. The targets may only lower integer representations they support.</p>
- These intrinsics take two arguments, the first a pointer to an integer value
- and the second an integer value. The result is also an integer value. These
- integer types can have any bit width, but they must all have the same bit
- width. The targets may only lower integer representations they support.
-</p>
<h5>Semantics:</h5>
-<p>
- These intrinsics does a series of operations atomically. They first load the
- value stored at <tt>ptr</tt>. They then do the bitwise operation
- <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
- value stored at <tt>ptr</tt>.
-</p>
+<p>These intrinsics does a series of operations atomically. They first load the
+ value stored at <tt>ptr</tt>. They then do the bitwise
+ operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
+ original value stored at <tt>ptr</tt>.</p>
<h5>Examples:</h5>
<pre>
-%ptr = malloc i32
- store i32 0x0F0F, %ptr
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
+ store i32 0x0F0F, %ptr
%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
<i>; yields {i32}:result0 = 0x0F0F</i>
%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
<i>; yields {i32}:result3 = FF</i>
%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
</pre>
-</div>
+</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
<a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
<a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
-
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
-<p>
- These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
- <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
- <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
- address spaces. Not all targets
- support all bit widths however.</p>
-<pre>
-declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.max.i64.p0i64( i64* <ptr>, i64 <delta> )
+<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
+ <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
+ <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
+ address spaces. Not all targets support all bit widths however.</p>
+<pre>
+ declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.max.i64.p0i64( i64* <ptr>, i64 <delta> )
</pre>
<pre>
-declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.min.i64..p0i64( i64* <ptr>, i64 <delta> )
-
+ declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.min.i64..p0i64( i64* <ptr>, i64 <delta> )
</pre>
<pre>
-declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* <ptr>, i64 <delta> )
-
+ declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* <ptr>, i64 <delta> )
</pre>
<pre>
-declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
-declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
-declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
-declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* <ptr>, i64 <delta> )
-
+ declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
+ declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
+ declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
+ declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* <ptr>, i64 <delta> )
</pre>
+
<h5>Overview:</h5>
-<p>
- These intrinsics takes the signed or unsigned minimum or maximum of
- <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
- original value at <tt>ptr</tt>.
-</p>
+<p>These intrinsics takes the signed or unsigned minimum or maximum of
+ <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
+ original value at <tt>ptr</tt>.</p>
+
<h5>Arguments:</h5>
-<p>
+<p>These intrinsics take two arguments, the first a pointer to an integer value
+ and the second an integer value. The result is also an integer value. These
+ integer types can have any bit width, but they must all have the same bit
+ width. The targets may only lower integer representations they support.</p>
- These intrinsics take two arguments, the first a pointer to an integer value
- and the second an integer value. The result is also an integer value. These
- integer types can have any bit width, but they must all have the same bit
- width. The targets may only lower integer representations they support.
-</p>
<h5>Semantics:</h5>
-<p>
- These intrinsics does a series of operations atomically. They first load the
- value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
- <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
- the original value stored at <tt>ptr</tt>.
-</p>
+<p>These intrinsics does a series of operations atomically. They first load the
+ value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
+ max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
+ yield the original value stored at <tt>ptr</tt>.</p>
<h5>Examples:</h5>
<pre>
-%ptr = malloc i32
- store i32 7, %ptr
+%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
+%ptr = bitcast i8* %mallocP to i32*
+ store i32 7, %ptr
%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
<i>; yields {i32}:result0 = 7</i>
%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
<i>; yields {i32}:result3 = 8</i>
%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
</pre>
+
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_memorymarkers">Memory Use Markers</a>
+</div>
+
+<div class="doc_text">
+
+<p>This class of intrinsics exists to information about the lifetime of memory
+ objects and ranges where variables are immutable.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ declare void @llvm.lifetime.start(i64 <size>, i8* nocapture <ptr>)
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
+ object's lifetime.</p>
+
+<h5>Arguments:</h5>
+<p>The first argument is a constant integer representing the size of the
+ object, or -1 if it is variable sized. The second argument is a pointer to
+ the object.</p>
+
+<h5>Semantics:</h5>
+<p>This intrinsic indicates that before this point in the code, the value of the
+ memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
+ never be used and has an undefined value. A load from the pointer that
+ precedes this intrinsic can be replaced with
+ <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ declare void @llvm.lifetime.end(i64 <size>, i8* nocapture <ptr>)
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
+ object's lifetime.</p>
+
+<h5>Arguments:</h5>
+<p>The first argument is a constant integer representing the size of the
+ object, or -1 if it is variable sized. The second argument is a pointer to
+ the object.</p>
+
+<h5>Semantics:</h5>
+<p>This intrinsic indicates that after this point in the code, the value of the
+ memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
+ never be used and has an undefined value. Any stores into the memory object
+ following this intrinsic may be removed as dead.
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ declare {}* @llvm.invariant.start(i64 <size>, i8* nocapture <ptr>) readonly
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
+ a memory object will not change.</p>
+
+<h5>Arguments:</h5>
+<p>The first argument is a constant integer representing the size of the
+ object, or -1 if it is variable sized. The second argument is a pointer to
+ the object.</p>
+
+<h5>Semantics:</h5>
+<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
+ the return value, the referenced memory location is constant and
+ unchanging.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ declare void @llvm.invariant.end({}* <start>, i64 <size>, i8* nocapture <ptr>)
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
+ a memory object are mutable.</p>
+
+<h5>Arguments:</h5>
+<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
+ The second argument is a constant integer representing the size of the
+ object, or -1 if it is variable sized and the third argument is a pointer
+ to the object.</p>
+
+<h5>Semantics:</h5>
+<p>This intrinsic indicates that the memory is mutable again.</p>
+
</div>
<!-- ======================================================================= -->
</div>
<div class="doc_text">
-<p> This class of intrinsics is designed to be generic and has
-no specific purpose. </p>
+
+<p>This class of intrinsics is designed to be generic and has no specific
+ purpose.</p>
+
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.var.annotation</tt>' intrinsic
-</p>
+<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
<h5>Arguments:</h5>
-
-<p>
-The first argument is a pointer to a value, the second is a pointer to a
-global string, the third is a pointer to a global string which is the source
-file name, and the last argument is the line number.
-</p>
+<p>The first argument is a pointer to a value, the second is a pointer to a
+ global string, the third is a pointer to a global string which is the source
+ file name, and the last argument is the line number.</p>
<h5>Semantics:</h5>
+<p>This intrinsic allows annotation of local variables with arbitrary strings.
+ This can be useful for special purpose optimizations that want to look for
+ these annotations. These have no other defined use, they are ignored by code
+ generation and optimization.</p>
-<p>
-This intrinsic allows annotation of local variables with arbitrary strings.
-This can be useful for special purpose optimizations that want to look for these
-annotations. These have no other defined use, they are ignored by code
-generation and optimization.
-</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_text">
<h5>Syntax:</h5>
-<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
-any integer bit width.
-</p>
+<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
+ any integer bit width.</p>
+
<pre>
declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.annotation</tt>' intrinsic.
-</p>
+<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
<h5>Arguments:</h5>
-
-<p>
-The first argument is an integer value (result of some expression),
-the second is a pointer to a global string, the third is a pointer to a global
-string which is the source file name, and the last argument is the line number.
-It returns the value of the first argument.
-</p>
+<p>The first argument is an integer value (result of some expression), the
+ second is a pointer to a global string, the third is a pointer to a global
+ string which is the source file name, and the last argument is the line
+ number. It returns the value of the first argument.</p>
<h5>Semantics:</h5>
+<p>This intrinsic allows annotations to be put on arbitrary expressions with
+ arbitrary strings. This can be useful for special purpose optimizations that
+ want to look for these annotations. These have no other defined use, they
+ are ignored by code generation and optimization.</p>
-<p>
-This intrinsic allows annotations to be put on arbitrary expressions
-with arbitrary strings. This can be useful for special purpose optimizations
-that want to look for these annotations. These have no other defined use, they
-are ignored by code generation and optimization.
-</p>
</div>
<!-- _______________________________________________________________________ -->
</pre>
<h5>Overview:</h5>
-
-<p>
-The '<tt>llvm.trap</tt>' intrinsic
-</p>
+<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
<h5>Arguments:</h5>
-
-<p>
-None
-</p>
+<p>None.</p>
<h5>Semantics:</h5>
+<p>This intrinsics is lowered to the target dependent trap instruction. If the
+ target does not have a trap instruction, this intrinsic will be lowered to
+ the call of the <tt>abort()</tt> function.</p>
-<p>
-This intrinsics is lowered to the target dependent trap instruction. If the
-target does not have a trap instruction, this intrinsic will be lowered to the
-call of the abort() function.
-</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
</div>
+
<div class="doc_text">
+
<h5>Syntax:</h5>
<pre>
-declare void @llvm.stackprotector( i8* <guard>, i8** <slot> )
+ declare void @llvm.stackprotector( i8* <guard>, i8** <slot> )
+</pre>
+
+<h5>Overview:</h5>
+<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
+ stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
+ ensure that it is placed on the stack before local variables.</p>
+
+<h5>Arguments:</h5>
+<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
+ arguments. The first argument is the value loaded from the stack
+ guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
+ that has enough space to hold the value of the guard.</p>
+
+<h5>Semantics:</h5>
+<p>This intrinsic causes the prologue/epilogue inserter to force the position of
+ the <tt>AllocaInst</tt> stack slot to be before local variables on the
+ stack. This is to ensure that if a local variable on the stack is
+ overwritten, it will destroy the value of the guard. When the function exits,
+ the guard on the stack is checked against the original guard. If they're
+ different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
+ function.</p>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ declare i32 @llvm.objectsize.i32( i8* <object>, i1 <type> )
+ declare i64 @llvm.objectsize.i64( i8* <object>, i1 <type> )
</pre>
+
<h5>Overview:</h5>
-<p>
- The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
- it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
- it is placed on the stack before local variables.
-</p>
+<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
+ to the optimizers to discover at compile time either a) when an
+ operation like memcpy will either overflow a buffer that corresponds to
+ an object, or b) to determine that a runtime check for overflow isn't
+ necessary. An object in this context means an allocation of a
+ specific class, structure, array, or other object.</p>
+
<h5>Arguments:</h5>
-<p>
- The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
- first argument is the value loaded from the stack guard
- <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
- has enough space to hold the value of the guard.
-</p>
+<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
+ argument is a pointer to or into the <tt>object</tt>. The second argument
+ is a boolean 0 or 1. This argument determines whether you want the
+ maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
+ 1, variables are not allowed.</p>
+
<h5>Semantics:</h5>
-<p>
- This intrinsic causes the prologue/epilogue inserter to force the position of
- the <tt>AllocaInst</tt> stack slot to be before local variables on the
- stack. This is to ensure that if a local variable on the stack is overwritten,
- it will destroy the value of the guard. When the function exits, the guard on
- the stack is checked against the original guard. If they're different, then
- the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
-</p>
+<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
+ representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
+ (depending on the <tt>type</tt> argument if the size cannot be determined
+ at compile time.</p>
+
</div>
<!-- *********************************************************************** -->
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