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-
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
+ "http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+ <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"
+ content="LLVM Assembly Language Reference Manual.">
+ <link rel="stylesheet" href="llvm.css" type="text/css">
+</head>
+
+<body>
+
+<div class="doc_title"> LLVM Language Reference Manual </div>
<ol>
- <li><a href="#abstract">Abstract</a>
- <li><a href="#introduction">Introduction</a>
- <li><a href="#identifiers">Identifiers</a>
+ <li><a href="#abstract">Abstract</a></li>
+ <li><a href="#introduction">Introduction</a></li>
+ <li><a href="#identifiers">Identifiers</a></li>
+ <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="#callingconv">Calling Conventions</a></li>
+ <li><a href="#globalvars">Global Variables</a></li>
+ <li><a href="#functionstructure">Functions</a></li>
+ <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
+ </ol>
+ </li>
<li><a href="#typesystem">Type System</a>
<ol>
- <li><a href="#t_primitive">Primitive Types</a>
- <ol>
- <li><a href="#t_classifications">Type Classifications</a>
+ <li><a href="#t_primitive">Primitive Types</a>
+ <li><a href="#t_classifications">Type Classifications</a></li>
</ol>
+ </li>
<li><a href="#t_derived">Derived Types</a>
<ol>
- <li><a href="#t_array" >Array Type</a>
- <li><a href="#t_method" >Method Type</a>
- <li><a href="#t_pointer">Pointer Type</a>
- <li><a href="#t_struct" >Structure Type</a>
- <li><a href="#t_packed" >Packed Type</a>
+ <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="#t_struct">Structure Type</a></li>
+ <li><a href="#t_packed">Packed Type</a></li>
+ <li><a href="#t_opaque">Opaque Type</a></li>
</ol>
+ </li>
</ol>
- <li><a href="#highlevel">High Level Structure</a>
+ </li>
+ <li><a href="#constants">Constants</a>
+ <ol>
+ <li><a href="#simpleconstants">Simple Constants</a>
+ <li><a href="#aggregateconstants">Aggregate Constants</a>
+ <li><a href="#globalconstants">Global Variable and Function Addresses</a>
+ <li><a href="#undefvalues">Undefined Values</a>
+ <li><a href="#constantexprs">Constant Expressions</a>
+ </ol>
+ </li>
+ <li><a href="#othervalues">Other Values</a>
<ol>
- <li><a href="#modulestructure">Module Structure</a>
- <li><a href="#methodstructure">Method Structure</a>
+ <li><a href="#inlineasm">Inline Assembler Expressions</a>
</ol>
+ </li>
<li><a href="#instref">Instruction Reference</a>
<ol>
<li><a href="#terminators">Terminator Instructions</a>
<ol>
- <li><a href="#i_ret" >'<tt>ret</tt>' Instruction</a>
- <li><a href="#i_br" >'<tt>br</tt>' Instruction</a>
- <li><a href="#i_switch" >'<tt>switch</tt>' Instruction</a>
- <li><a href="#i_callwith">'<tt>call .. with</tt>' Instruction</a>
- </ol>
- <li><a href="#unaryops">Unary Operations</a>
- <ol>
- <li><a href="#i_not" >'<tt>not</tt>' Instruction</a>
- <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</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_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>
</ol>
+ </li>
<li><a href="#binaryops">Binary Operations</a>
<ol>
- <li><a href="#i_add" >'<tt>add</tt>' Instruction</a>
- <li><a href="#i_sub" >'<tt>sub</tt>' Instruction</a>
- <li><a href="#i_mul" >'<tt>mul</tt>' Instruction</a>
- <li><a href="#i_div" >'<tt>div</tt>' Instruction</a>
- <li><a href="#i_rem" >'<tt>rem</tt>' Instruction</a>
- <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a>
+ <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
+ <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
+ <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
+ <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
+ <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
+ <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
</ol>
+ </li>
<li><a href="#bitwiseops">Bitwise Binary Operations</a>
<ol>
- <li><a href="#i_and">'<tt>and</tt>' Instruction</a>
- <li><a href="#i_or" >'<tt>or</tt>' Instruction</a>
- <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a>
- <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a>
- <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a>
+ <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
+ <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
+ <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
+ <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
+ <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
+ </ol>
+ </li>
+ <li><a href="#vectorops">Vector Operations</a>
+ <ol>
+ <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
+ <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
+ <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
+ <li><a href="#i_vsetint">'<tt>vsetint</tt>' Instruction</a></li>
+ <li><a href="#i_vsetfp">'<tt>vsetfp</tt>' Instruction</a></li>
+ <li><a href="#i_vselect">'<tt>vselect</tt>' Instruction</a></li>
</ol>
+ </li>
<li><a href="#memoryops">Memory Access Operations</a>
<ol>
- <li><a href="#i_malloc" >'<tt>malloc</tt>' Instruction</a>
- <li><a href="#i_free" >'<tt>free</tt>' Instruction</a>
- <li><a href="#i_alloca" >'<tt>alloca</tt>' Instruction</a>
- <li><a href="#i_load" >'<tt>load</tt>' Instruction</a>
- <li><a href="#i_store" >'<tt>store</tt>' Instruction</a>
- <li><a href="#i_getfieldptr">'<tt>getfieldptr</tt>' Instruction</a>
+ <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>
+ <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
</ol>
+ </li>
<li><a href="#otherops">Other Operations</a>
<ol>
- <li><a href="#i_call" >'<tt>call</tt>' Instruction</a>
- <li><a href="#i_icall">'<tt>icall</tt>' Instruction</a>
- <li><a href="#i_phi" >'<tt>phi</tt>' Instruction</a>
+ <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
+ <li><a href="#i_cast">'<tt>cast .. to</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="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
</ol>
- <li><a href="#builtinfunc">Builtin Functions</a>
- </ol>
- <li><a href="#todo">TODO List</a>
- <ol>
- <li><a href="#exception">Exception Handling Instructions</a>
- <li><a href="#synchronization">Synchronization Instructions</a>
+ </li>
</ol>
- <li><a href="#extensions">Possible Extensions</a>
+ </li>
+ <li><a href="#intrinsics">Intrinsic Functions</a>
<ol>
- <li><a href="#i_tailcall">'<tt>tailcall</tt>' Instruction</a>
- <li><a href="#globalvars">Global Variables</a>
- <li><a href="#explicitparrellelism">Explicit Parrellelism</a>
+ <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
+ <ol>
+ <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
+ <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
+ <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
+ <ol>
+ <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
+ <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
+ <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_codegen">Code Generator Intrinsics</a>
+ <ol>
+ <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
+ <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
+ <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
+ <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
+ <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
+ <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
+ <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_libc">Standard C Library Intrinsics</a>
+ <ol>
+ <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
+ <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
+ <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
+ <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
+ <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
+
+ </ol>
+ </li>
+ <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
+ <ol>
+ <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</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>
+ </ol>
+ </li>
+ <li><a href="#int_debugger">Debugger intrinsics</a></li>
</ol>
- <li><a href="#related">Related Work</a>
+ </li>
</ol>
+<div class="doc_author">
+ <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
+ and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
+</div>
<!-- *********************************************************************** -->
-<p><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="abstract">Abstract
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="abstract">Abstract </a></div>
<!-- *********************************************************************** -->
-<blockquote>
- This document describes the LLVM assembly language IR/VM. LLVM is an SSA
- based representation that attempts to be a useful midlevel IR by providing
- type safety, low level operations, flexibility, and the capability to
- represent 'all' high level languages cleanly.
-</blockquote>
-
-
-
+<div class="doc_text">
+<p>This document is a reference manual for the LLVM assembly language.
+LLVM is an 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>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="introduction">Introduction
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="introduction">Introduction</a> </div>
<!-- *********************************************************************** -->
-The LLVM is designed to exhibit a dual nature: on one hand, it is a useful compiler IR, on the other hand, it is a bytecode representation for dynamic compilation. We contend that this is a natural and good thing, making LLVM a natural form of communication between different compiler phases, and also between a static and dynamic compiler.<p>
-
-This dual nature leads to three different representations of LLVM (the human readable assembly representation, the compact bytecode representation, and the in memory, pointer based, representation). This document describes the human readable representation and notation.<p>
-
-The LLVM representation aims to be a light weight and low level while being expressive, type safe, 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. By providing type safety, 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 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 bytecode
+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>
+
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="wellformed"><h4><hr size=0>Well Formedness</h4><ul>
+<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
+
+<div class="doc_text">
-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>
<pre>
%x = <a href="#i_add">add</a> int 1, %x
</pre>
-...because only a <tt><a href="#i_phi">phi</a></tt> node may refer to itself. The LLVM api provides a verification function (<tt>verify</tt>) that may be used to verify that a whole module or a single method is well formed. It is useful to validate whether an optimization pass performed a well formed transformation to the code.<p>
-
-
-Describe the typesetting conventions here.
+<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 bytecode. The violations pointed out
+by the verifier pass indicate bugs in transformation passes or input to
+the parser.</p>
+<!-- Describe the typesetting conventions here. --> </div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="identifiers">Identifiers
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
<!-- *********************************************************************** -->
-LLVM uses three different forms of identifiers, for different purposes:<p>
+<div class="doc_text">
+
+<p>LLVM uses three different forms of identifiers, for different
+purposes:</p>
<ol>
-<li>Numeric constants are represented as you would expect: 12, -3 123.421, etc.
-<li>Named values are represented as a string of characters with a '%' 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>'.
-<li>Unnamed values are represented as an unsigned numeric value with a '%' prefix. For example, %12, %2, %44.
-</ol><p>
+ <li>Named values are represented as a string of characters with a '%' 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. In this way, anything except a <tt>"</tt> character can be used
+ in a name.</li>
+
+ <li>Unnamed values are represented as an unsigned numeric value with a '%'
+ prefix. For example, %12, %2, %44.</li>
+
+ <li>Constants, which are described in a <a href="#constants">section about
+ constants</a>, below.</li>
+</ol>
-LLVM requires the values start with a '%' sign 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>
+<p>LLVM requires that values start with a '%' sign 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>
-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_cast">cast</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_uint">uint</a></tt>', etc...), and others. These reserved words cannot conflict with variable names, because none of them may start with a '%' character.<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_cast">cast</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_uint">uint</a></tt>', etc...),
+and others. These reserved words cannot conflict with variable names, because
+none of them start with a '%' character.</p>
-Here is an example of LLVM code to multiply the integer variable '<tt>%X</tt>' by 8:<p>
+<p>Here is an example of LLVM code to multiply the integer variable
+'<tt>%X</tt>' by 8:</p>
+
+<p>The easy way:</p>
-The easy way:
<pre>
- %result = <a href="#i_mul">mul</a> int %X, 8
+ %result = <a href="#i_mul">mul</a> uint %X, 8
</pre>
-After strength reduction:
+<p>After strength reduction:</p>
+
<pre>
- %result = <a href="#i_shl">shl</a> int %X, ubyte 3
+ %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
</pre>
-And the hard way:
+<p>And the hard way:</p>
+
<pre>
- <a href="#i_add">add</a> int %X, %X <i>; yields {int}:%0</i>
- <a href="#i_add">add</a> int %0, %0 <i>; yields {int}:%1</i>
- %result = <a href="#i_add">add</a> int %1, %1
+ <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
+ <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
+ %result = <a href="#i_add">add</a> uint %1, %1
</pre>
-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>Unnamed temporaries are created when the result of a computation is not assigned to a named value.
-<li>Unnamed temporaries are numbered sequentially
-</ol><p>
-...and it also show 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>
+ <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
+ line.</li>
+
+ <li>Unnamed temporaries are created when the result of a computation is not
+ 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>
+
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="typesystem">Type System
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
<!-- *********************************************************************** -->
-The LLVM type system is important to the overall usefulness of the language and VM runtime. By being strongly typed, a number of optimizations may be performed on the IR directly, without having to do extra analysis to derive types. A strong type system also makes it easier to comprehend generated code and assists with safety concerns.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
+</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>
+
+<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 sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
+
+<i>; External declaration of the puts function</i>
+<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
+
+<i>; Global variable / Function body section separator</i>
+implementation
+
+<i>; Definition of main function</i>
+int %main() { <i>; int()* </i>
+ <i>; Convert [13x sbyte]* to sbyte *...</i>
+ %cast210 = <a
+ href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
+
+ <i>; Call puts function to write out the string to stdout...</i>
+ <a
+ href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
+ <a
+ href="#i_ret">ret</a> int 0<br>}<br></pre>
+
+<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>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>Due to a limitation in the current LLVM assembly parser (it is limited by
+one-token lookahead), modules are split into two pieces by the "implementation"
+keyword. Global variable prototypes and definitions must occur before the
+keyword, and function definitions must occur after it. Function prototypes may
+occur either before or after it. In the future, the implementation keyword may
+become a noop, if the parser gets smarter.</p>
+
+</div>
-The assembly language form for the type system was heavily influenced by the type problems in the C language<sup><a href="#rw_stroustrup">1</a></sup>.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="linkage">Linkage Types</a>
+</div>
+<div class="doc_text">
+<p>
+All Global Variables and Functions have one of the following types of linkage:
+</p>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="t_primitive">Primitive Types
-</b></font></td></tr></table><ul>
-
-The primitive types are the fundemental building blocks of the LLVM system. The current set of primitive types are as follows:<p>
-
-<table border=0 align=center><tr><td>
-
-<table border=1 cellspacing=0 cellpadding=4 align=center>
-<tr><td><tt>void</tt></td> <td>No value</td></tr>
-<tr><td><tt>ubyte</tt></td> <td>Unsigned 8 bit value</td></tr>
-<tr><td><tt>ushort</tt></td><td>Unsigned 16 bit value</td></tr>
-<tr><td><tt>uint</tt></td> <td>Unsigned 32 bit value</td></tr>
-<tr><td><tt>ulong</tt></td> <td>Unsigned 64 bit value</td></tr>
-<tr><td><tt>float</tt></td> <td>32 bit floating point value</td></tr>
-<tr><td><tt>label</tt></td> <td>Branch destination</td></tr>
-</table>
+<dl>
-</td><td>
+ <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
-<table border=1 cellspacing=0 cellpadding=4 align=center>
-<tr><td><tt>bool</tt></td> <td>True or False value</td></tr>
-<tr><td><tt>sbyte</tt></td> <td>Signed 8 bit value</td></tr>
-<tr><td><tt>short</tt></td> <td>Signed 16 bit value</td></tr>
-<tr><td><tt>int</tt></td> <td>Signed 32 bit value</td></tr>
-<tr><td><tt>long</tt></td> <td>Signed 64 bit value</td></tr>
-<tr><td><tt>double</tt></td><td>64 bit floating point value</td></tr>
-<tr><td><tt>lock</tt></td> <td>Recursive mutex value</td></tr>
-</table>
+ <dd>Global values with internal linkage are only directly accessible by
+ objects in the current module. In particular, linking code into a module with
+ an internal global value may cause the internal to be renamed as necessary to
+ avoid collisions. Because the symbol is internal to the module, all
+ references can be updated. This corresponds to the notion of the
+ '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
+ </dd>
-</td></tr></table><p>
+ <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
+ <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
+ the twist that linking together two modules defining the same
+ <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
+ is typically used to implement inline functions. Unreferenced
+ <tt>linkonce</tt> globals are allowed to be discarded.
+ </dd>
+ <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_classifications"><h4><hr size=0>Type Classifications</h4><ul>
+ <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
+ except that unreferenced <tt>weak</tt> globals may not be discarded. This is
+ used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
+ </dd>
-These different primitive types fall into a few useful classifications:<p>
+ <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
-<table border=1 cellspacing=0 cellpadding=4 align=center>
-<tr><td><a name="t_signed">signed</td> <td><tt>sbyte, short, int, long, float, double</tt></td></tr>
-<tr><td><a name="t_unsigned">unsigned</td><td><tt>ubyte, ushort, uint, ulong</tt></td></tr>
-<tr><td><a name="t_integral">integral</td><td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td></tr>
-<tr><td><a name="t_floating">floating point</td><td><tt>float, double</tt></td></tr>
-<tr><td><a name="t_firstclass">first class</td><td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long, float, double, lock</tt></td></tr>
-</table><p>
+ <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_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>
+</dl>
+<p><a name="linkage_external">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. It is illegal for a function <i>declaration</i>
+to have any linkage type other than "externally visible".</a></p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="t_derived">Derived Types
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="callingconv">Calling Conventions</a>
+</div>
+
+<div class="doc_text">
-The real power in LLVM comes from the derived types in the system. This is what allows a programmer to represent arrays, methods, 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>
+<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>
+<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>
+
+ <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
+
+ <dd>This calling convention matches the target C calling conventions, except
+ that functions with this convention are required to take a pointer as their
+ first argument, and the return type of the function must be void. This is
+ used for C functions that return aggregates by-value. In this case, the
+ function has been transformed to take a pointer to the struct as the first
+ argument to the function. For targets where the ABI specifies specific
+ behavior for structure-return calls, the calling convention can be used to
+ distinguish between struct return functions and other functions that take a
+ pointer to a struct as the first argument.
+ </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. Implementations of
+ this convention should allow arbitrary tail call optimization 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>
+
+ <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>
+
+ <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>
+</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>
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_array"><h4><hr size=0>Array Type</h4><ul>
+</div>
-<h5>Overview:</h5>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="globalvars">Global Variables</a>
+</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 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>LLVM allows an explicit section to be specified for globals. If the target
+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>
+
+</div>
-The array type is a very simple derived type. It arranges elements sequentially in memory. There are two different forms of the array type:<p>
-<ol>
-<a name="t_array_fixed"><b><li>Fixed size array type:</b><br>
- The simplest form of the array type, has a size hard coded in as part of the type. Thus these are three distinct type qualifiers:<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="functionstructure">Functions</a>
+</div>
+
+<div class="doc_text">
+
+<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
+type</a>, an optional <a href="#callingconv">calling convention</a>, a return
+type, a function name, a (possibly empty) argument list, an optional section,
+an optional alignment, an opening curly brace,
+a list of basic blocks, and a closing curly brace. LLVM function declarations
+are defined with the "<tt>declare</tt>" keyword, an optional <a
+href="#callingconv">calling convention</a>, a return type, a function name,
+a possibly empty list of arguments, and an optional alignment.</p>
+
+<p>A function definition contains a list of basic blocks, forming the CFG 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 program 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>
+
+<p>LLVM functions are identified by their name and type signature. Hence, two
+functions with the same name but different parameter lists or return values are
+considered different functions, and LLVM will resolve references to each
+appropriately.</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>
+
+<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>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="moduleasm">Module-Level Inline Assembly</a>
+</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>
+
+<div class="doc_code"><pre>
+ module asm "inline asm code goes here"
+ module asm "more can go here"
+</pre></div>
+
+<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>
+
+<p>
+ The inline asm code is simply printed to the machine code .s file when
+ assembly code is generated.
+</p>
+</div>
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section"> <a name="typesystem">Type System</a> </div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
- <tt>[40 x int ]</tt>: Array of 40 integer values.<br>
- <tt>[41 x int ]</tt>: Array of 41 integer values.<br>
- <tt>[40 x uint]</tt>: Array of 40 unsigned integer values.<p>
+<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 IR 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>
-Fixed sized arrays are very useful for compiler optimization passes and for representing analysis results. Additionally, multidimensional arrays must have fixed sizes for all dimensions except the outer-most dimension.<p>
+</div>
-<a name="t_array_unsized"><b><li>Dynamically sized array type:</b><br>
- The dynamically sized arrays are very similar to the fixed size arrays, except that the size of the array is calculated at runtime by the virtual machine. This is useful for representing generic methods that take any size array as an argument, or when representing Java style arrays.
-</ol><p>
+<!-- ======================================================================= -->
+<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. The current set of primitive types is as follows:</p>
+
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <table>
+ <tbody>
+ <tr><th>Type</th><th>Description</th></tr>
+ <tr><td><tt>void</tt></td><td>No value</td></tr>
+ <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
+ <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
+ <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
+ <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
+ <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
+ <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
+ </tbody>
+ </table>
+ </td>
+ <td class="right">
+ <table>
+ <tbody>
+ <tr><th>Type</th><th>Description</th></tr>
+ <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
+ <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
+ <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
+ <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
+ <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
+ <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
+ </tbody>
+ </table>
+ </td>
+ </tr>
+</table>
+</div>
-Here are some examples of multidimensional arrays:<p>
-<ul>
-<table border=0 cellpadding=0 cellspacing=0>
-<tr><td><tt>[3 x [4 x int]]</tt></td><td>: 3x4 array integer values.</td></tr>
-<tr><td><tt>[[10 x int]]</tt></td><td>: Nx10 array of integer values.</td></tr>
-<tr><td><tt>[2 x [3 x [4 x uint]]]</tt></td><td>: 2x3x4 array of unsigned integer values.</td></tr>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_classifications">Type
+Classifications</a> </div>
+<div class="doc_text">
+<p>These different primitive types fall into a few useful
+classifications:</p>
+
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr><th>Classification</th><th>Types</th></tr>
+ <tr>
+ <td><a name="t_signed">signed</a></td>
+ <td><tt>sbyte, short, int, long, float, double</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_unsigned">unsigned</a></td>
+ <td><tt>ubyte, ushort, uint, ulong</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_integer">integer</a></td>
+ <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_integral">integral</a></td>
+ <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
+ </td>
+ </tr>
+ <tr>
+ <td><a name="t_floating">floating point</a></td>
+ <td><tt>float, double</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_firstclass">first class</a></td>
+ <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
+ float, double, <a href="#t_pointer">pointer</a>,
+ <a href="#t_packed">packed</a></tt></td>
+ </tr>
+ </tbody>
</table>
-</ul>
+<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. This means that all structures and arrays must be
+manipulated either by pointer or by component.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </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>
<!-- _______________________________________________________________________ -->
-</ul><a name="t_method"><h4><hr size=0>Method Type</h4><ul>
+<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
+
+<div class="doc_text">
<h5>Overview:</h5>
-The method type can be thought of as a method signature. It consists of a return type and a list of formal parameter types. Method types are usually used when to build virtual function tables (which are structures of pointers to methods) and for indirect method calls.<p>
+<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>
<h5>Syntax:</h5>
+
<pre>
- <returntype> (<parameter list>)
+ [<# elements> x <elementtype>]
</pre>
-Where '<tt><parameter list></tt>' is a comma seperated list of type specifiers.<p>
+<p>The number of elements is a constant integer value; elementtype may
+be any type with a size.</p>
<h5>Examples:</h5>
-<ul>
-<table border=0 cellpadding=0 cellspacing=0>
-<tr><td><tt>int (int)</tt></td><td>: method taking an <tt>int</tt>, returning an <tt>int</tt></td></tr>
-<tr><td><tt>float (int, int *) *</tt></td><td>: <a href="#t_pointer">Pointer</a> to a method that takes an <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>, returning <tt>float</tt>.</td></tr>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>[40 x int ]</tt><br/>
+ <tt>[41 x int ]</tt><br/>
+ <tt>[40 x uint]</tt><br/>
+ </td>
+ <td class="left">
+ Array of 40 integer values.<br/>
+ Array of 41 integer values.<br/>
+ Array of 40 unsigned integer values.<br/>
+ </td>
+ </tr>
+</table>
+<p>Here are some examples of multidimensional arrays:</p>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>[3 x [4 x int]]</tt><br/>
+ <tt>[12 x [10 x float]]</tt><br/>
+ <tt>[2 x [3 x [4 x uint]]]</tt><br/>
+ </td>
+ <td class="left">
+ 3x4 array of integer values.<br/>
+ 12x10 array of single precision floating point values.<br/>
+ 2x3x4 array of unsigned integer values.<br/>
+ </td>
+ </tr>
</table>
-</ul>
+<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 "{ int, [0 x float]}", 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.
+Function types are usually used to build virtual function tables
+(which are structures of pointers to functions), for indirect function
+calls, and when defining a function.</p>
+<p>
+The return type of a function type cannot be an aggregate type.
+</p>
+<h5>Syntax:</h5>
+<pre> <returntype> (<parameter list>)<br></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.</p>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>int (int)</tt> <br/>
+ <tt>float (int, int *) *</tt><br/>
+ <tt>int (sbyte *, ...)</tt><br/>
+ </td>
+ <td class="left">
+ function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
+ <a href="#t_pointer">Pointer</a> to a function that takes an
+ <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
+ returning <tt>float</tt>.<br/>
+ A vararg function that takes at least one <a href="#t_pointer">pointer</a>
+ to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
+ the signature for <tt>printf</tt> in LLVM.<br/>
+ </td>
+ </tr>
+</table>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="t_struct"><h4><hr size=0>Structure Type</h4><ul>
+<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>
+<h5>Syntax:</h5>
+<pre> { <type list> }<br></pre>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>{ int, int, int }</tt><br/>
+ <tt>{ float, int (int) * }</tt><br/>
+ </td>
+ <td class="left">
+ a triple of three <tt>int</tt> values<br/>
+ A pair, where the first element is a <tt>float</tt> and the second element
+ is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
+ that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
+ </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.</p>
+<h5>Syntax:</h5>
+<pre> <type> *<br></pre>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>[4x int]*</tt><br/>
+ <tt>int (int *) *</tt><br/>
+ </td>
+ <td class="left">
+ A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
+ four <tt>int</tt> values<br/>
+ A <a href="#t_pointer">pointer</a> to a <a
+ href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
+ <tt>int</tt>.<br/>
+ </td>
+ </tr>
+</table>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
+<div class="doc_text">
-The structure type is used to represent a collection of data members together in memory. Although the runtime is allowed to lay out the data members any way that it would like, they are guaranteed to be "close" to each other.<p>
+<h5>Overview:</h5>
-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_getfieldptr">getfieldptr</a></tt>' instruction.<p>
+<p>A packed type is a simple derived type that represents a vector
+of elements. Packed types are used when multiple primitive data
+are operated in parallel using a single instruction (SIMD).
+A packed 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 ...). Packed types are
+considered <a href="#t_firstclass">first class</a>.</p>
<h5>Syntax:</h5>
+
<pre>
- { <type list> }
+ < <# elements> x <elementtype> >
</pre>
+<p>The number of elements is a constant integer value; elementtype may
+be any integral or floating point type.</p>
<h5>Examples:</h5>
-<table border=0 cellpadding=0 cellspacing=0>
-<tr><td><tt>{ int, int, int }</tt></td><td>: a triple of three <tt>int</tt> values</td></tr>
-<tr><td><tt>{ float, int (int *) * }</tt></td><td>: A pair, where the first element is a <tt>float</tt> and the second element is a <a href="#t_pointer">pointer</a> to a <a href="t_method">method</a> that takes an <tt>int</tt>, returning an <tt>int</tt>.</td></tr>
-</table>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt><4 x int></tt><br/>
+ <tt><8 x float></tt><br/>
+ <tt><2 x uint></tt><br/>
+ </td>
+ <td class="left">
+ Packed vector of 4 integer values.<br/>
+ Packed vector of 8 floating-point values.<br/>
+ Packed vector of 2 unsigned integer values.<br/>
+ </td>
+ </tr>
+</table>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="t_pointer"><h4><hr size=0>Pointer Type</h4><ul>
+<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
+<div class="doc_text">
+<h5>Overview:</h5>
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_packed"><h4><hr size=0>Packed Type</h4><ul>
+<p>Opaque types are used to represent unknown types in the system. This
+corresponds (for example) to the C notion of a foward declared structure type.
+In LLVM, opaque types can eventually be resolved to any type (not just a
+structure type).</p>
+
+<h5>Syntax:</h5>
-Mention/decide that packed types work with saturation or not. Maybe have a packed+saturated type in addition to just a packed type.<p>
+<pre>
+ opaque
+</pre>
+
+<h5>Examples:</h5>
-Packed types should be 'nonsaturated' because standard data types are not saturated. Maybe have a saturated packed type?<p>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>opaque</tt>
+ </td>
+ <td class="left">
+ An opaque type.<br/>
+ </td>
+ </tr>
+</table>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="highlevel">High Level Structure
-</b></font></td></tr></table><ul>
+<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>
+
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="modulestructure">Module Structure
-</b></font></td></tr></table><ul>
+<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
+
+<div class="doc_text">
+<dl>
+ <dt><b>Boolean constants</b></dt>
-talk about the elements of a module: constant pool and method list.<p>
+ <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
+ constants of the <tt><a href="#t_primitive">bool</a></tt> type.
+ </dd>
+ <dt><b>Integer constants</b></dt>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="methodstructure">Method Structure
-</b></font></td></tr></table><ul>
+ <dd>Standard integers (such as '4') are constants of the <a
+ href="#t_integer">integer</a> type. Negative numbers may be used with signed
+ integer types.
+ </dd>
+ <dt><b>Floating point constants</b></dt>
-talk about the constant pool<p>
-talk about how basic blocks delinate labels<p>
-talk about how basic blocks end with terminators<p>
+ <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). Floating point constants must have a <a
+ href="#t_floating">floating point</a> type. </dd>
+ <dt><b>Null pointer constants</b></dt>
-<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="instref">Instruction Reference
-</b></font></td></tr></table><ul>
-<!-- *********************************************************************** -->
+ <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>
-List all of the instructions, list valid types that they accept. Tell what they
-do and stuff also.
+</dl>
+
+<p>The one non-intuitive notation for constants is the optional 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. 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>
+
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="terminators">Terminator Instructions
-</b></font></td></tr></table><ul>
+<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
+</div>
+<div class="doc_text">
+<p>Aggregate constants arise from aggregation of simple constants
+and smaller aggregate 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>{ int 4, float 17.0, int* %G }</tt>",
+ where "<tt>%G</tt>" is declared as "<tt>%G = external global int</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>[ int 42, int 11, int 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>Packed constants</b></dt>
+
+ <dd>Packed constants are represented with notation similar to packed type
+ definitions (a comma separated list of elements, surrounded by
+ less-than/greater-than's (<tt><></tt>)). For example: "<tt>< int 42,
+ int 11, int 74, int 100 ></tt>". Packed constants must have <a
+ href="#t_packed">packed 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>
+</dl>
-As was mentioned <a href="#methodstructure">previously</a>, every basic block in
-a program ends with a "Terminator" instruction. Additionally, all terminators yield a '<tt>void</tt>' value: they produce control flow, not values.<p>
+</div>
-There are three different terminator instructions: the '<a href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>' instruction, and the '<a href="#i_switch"><tt>switch</tt></a>' instruction.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="globalconstants">Global Variable and Function Addresses</a>
+</div>
+<div class="doc_text">
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_ret"><h4><hr size=0>'<tt>ret</tt>' Instruction</h4><ul>
+<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>
-<h5>Syntax:</h5>
<pre>
- ret <type> <value> <i>; Return a value from a non-void method</i>
- ret void <i>; Return from void method</i>
+ %X = global int 17
+ %Y = global int 42
+ %Z = global [2 x int*] [ int* %X, int* %Y ]
</pre>
-<h5>Overview:</h5>
-The '<tt>ret</tt>' instruction is used to return control flow (and optionally a value) from a method, back to the caller.<p>
+</div>
-There are two forms of the '<tt>ret</tt>' instructruction: one that returns a value and then causes control flow, and one that just causes control flow to occur.<p>
+<!-- ======================================================================= -->
+<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>
-<h5>Arguments:</h5>
-The '<tt>ret</tt>' instruction may return any '<a href="#t_firstclass">first class</a>' type. Notice that a method is not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>' instruction inside of the method that returns a value that does not match the return type of the method.<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>
+</div>
-<h5>Semantics:</h5>
-When the '<tt>ret</tt>' instruction is executed, control flow returns back to the calling method's context. If the instruction returns a value, that value shall be propogated into the calling method's data space.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
+</div>
-<h5>Example:</h5>
-<pre>
- ret int 5 <i>; Return an integer value of 5</i>
- ret void <i>; Return from a void method</i>
-</pre>
+<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>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_br"><h4><hr size=0>'<tt>br</tt>' Instruction</h4><ul>
+<dl>
+ <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
-<h5>Syntax:</h5>
-<pre>
- br bool <cond>, label <iftrue>, label <iffalse>
- br label <dest> <i>; Unconditional branch</i>
-</pre>
+ <dd>Cast a constant to another type.</dd>
-<h5>Overview:</h5>
-The '<tt>br</tt>' instruction is used to cause control flow to transfer to a different basic block in the current method. There are two forms of this instruction, corresponding to a conditional branch and an unconditional branch. The '<tt>br</tt>' instruction is a (useful) special case '<tt><a href="#i_switch">switch</a></tt>' instruction.<p>
+ <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
-<h5>Arguments:</h5>
+ <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>
-The conditional branch form of the '<tt>br</tt>' instruction shall take a single '<tt>bool</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>
+ <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
-<h5>Semantics:</h5>
+ <dd>Perform the <a href="#i_select">select operation</a> on
+ constants.
-Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</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>
+ <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
-<h5>Example:</h5>
-<pre>
-Test:
- %cond = <a href="#i_setcc">seteq</a> int %a, %b
- br bool %cond, label %IfEqual, label %IfUnequal
-IfEqual:
- <a href="#i_ret">ret</a> bool true
-IfUnequal:
- <a href="#i_ret">ret</a> bool false
-</pre>
+ <dd>Perform the <a href="#i_extractelement">extractelement
+ operation</a> on constants.
+ <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_switch"><h4><hr size=0>'<tt>switch</tt>' Instruction</h4><ul>
+ <dd>Perform the <a href="#i_insertelement">insertelement
+ operation</a> on constants.
-<h5>Syntax:</h5>
-<pre>
- <i>; Definitions for lookup indirect branch</i>
- %switchtype = type [<anysize> x { uint, label }]
- <i>; Lookup indirect branch</i>
- switch uint <value>, label <defaultdest>, %switchtype <switchtable>
+ <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
- <i>; Indexed indirect branch</i>
- switch uint <idxvalue>, label <defaultdest>, [<anysize> x label] <desttable>
-</pre>
+ <dd>Perform the <a href="#i_shufflevector">shufflevector
+ operation</a> on constants.
-<h5>Overview:</h5>
-The '<tt>switch</tt>' instruction is used to transfer control flow to one of several different places. It is a simple generalization of the '<tt>br</tt>' instruction, and supports a strict superset of its functionality.<p>
+ <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
-The '<tt>switch</tt>' statement supports two different styles of indirect branching: lookup branching and indexed branching. Lookup branching is generally useful if the values to switch on are spread far appart, where index branching is useful if the values to switch on are generally dense.<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>
-The two different forms of the '<tt>switch</tt>' statement are simple hints to the underlying virtual machine implementation. For example, a virtual machine may choose to implement a small indirect branch table as a series of predicated comparisons: if it is faster for the target architecture.<p>
+<!-- *********************************************************************** -->
+<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
+<!-- *********************************************************************** -->
-<h5>Arguments:</h5>
-The lookup form of the '<tt>switch</tt>' instruction uses three parameters: a '<tt>uint</tt>' comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and a sized array of pairs of comparison value constants and '<tt>label</tt>'s. The sized array must be a constant value.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+<a name="inlineasm">Inline Assembler Expressions</a>
+</div>
-The indexed form of the '<tt>switch</tt>' instruction uses three parameters: an '<tt>uint</tt>' index value, a default '<tt>label</tt>' and a sized array of '<tt>label</tt>'s. The '<tt>dests</tt>' array must be a constant array.
+<div class="doc_text">
-<h5>Semantics:</h5>
+<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>
-The lookup style switch statement 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, the corresponding destination is branched to. <p>
-The index branch form simply looks up a label element directly in a table and branches to it.<p>
+<pre>
+ int(int) asm "bswap $0", "=r,r"
+</pre>
-In either case, the compiler knows the static size of the array, because it is provided as part of the constant values type.<p>
+<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>
-<h5>Example:</h5>
<pre>
- <i>; Emulate a conditional br instruction</i>
- %Val = <a href="#i_cast">cast</a> bool %value to uint
- switch uint %Val, label %truedest, [1 x label] [label %falsedest ]
+ %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y)
+</pre>
- <i>; Emulate an unconditional br instruction</i>
- switch uint 0, label %dest, [ 0 x label] [ ]
+<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>
- <i>; Implement a jump table using the constant pool:</i>
- void "testmeth"(int %arg0)
- %switchdests = [3 x label] [ label %onzero, label %onone, label %ontwo ]
- {
- ...
- switch uint %val, label %otherwise, [3 x label] %switchdests...
- ...
- }
+<pre>
+ call void asm sideeffect "eieio", ""()
+</pre>
- <i>; Implement the equivilent jump table directly:</i>
- switch uint %val, label %otherwise, [3 x label] [ label %onzero,
- label %onone,
- label %ontwo ]
+<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).
+</p>
-</pre>
+</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>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="terminators">Terminator
+Instructions</a> </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>
+
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_callwith"><h4><hr size=0>'<tt>call .. with</tt>' Instruction</h4><ul>
+<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>
+ ret void <i>; Return from void function</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>ret</tt>' instruction is used to return control flow (and 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>
+<h5>Arguments:</h5>
+<p>The '<tt>ret</tt>' instruction may return any '<a
+ href="#t_firstclass">first class</a>' type. Notice that a function is
+not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
+instruction inside of the function that returns a value that does not
+match the return type of the function.</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>
+<h5>Example:</h5>
+<pre> ret int 5 <i>; Return an integer value of 5</i>
+ ret void <i>; Return from a void function</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> br bool <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>
+<h5>Arguments:</h5>
+<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
+single '<tt>bool</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>bool</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>
+<h5>Example:</h5>
+<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
+ href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_switch">'<tt>switch</tt>' Instruction</a>
+</div>
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = call <method ty> %<method name>(<method args>) with label <break label>
+ switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
</pre>
<h5>Overview:</h5>
-The '<tt>call .. with</tt>' instruction is used to cause control flow to transfer to a specified method, with the possibility of control flow transfer to the '<tt>break label</tt>' label, in addition to the possibility of fallthrough to the next basic block. The '<tt><a href="#i_call">call</a></tt>' instruction is closely related, but does guarantees that control flow either never returns from the invoked method, or that it returns to the instruction succeeding the '<tt><a href="#i_call">call</a></tt>' instruction.<p>
-TODO: icall .. with needs to be defined as well for an indirect call.<p>
+<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>
+
<h5>Arguments:</h5>
-This instruction requires several arguments:<p>
-<ol>
-<li>'<tt>method ty</tt>': shall be the signature of the named method being invoked. This must be a <a href="#t_method">method type</a>.
-<li>'<tt>method name</tt>': method name to be invoked.
-<li>'<tt>method args</tt>': argument list whose types match the method signature argument types.
-<li>'<tt>break label</tt>': a label that specifies the break label associated with this call.
-</ol>
+<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>
<h5>Semantics:</h5>
-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 assiciates a label with the method invocation that may be accessed via the runtime library provided by the execution environment. 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>
-
-For a more comprehensive explanation of this instruction look in the llvm/docs/2001-05-18-ExceptionHandling.txt document.
-
-<h5>Example:</h5>
-<pre>
- %retval = call int (int) %Test(int 15) with label %TestCleanup <i>; {int}:retval set</i>
-</pre>
+<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>
+<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>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="unaryops">Unary Operations
-</b></font></td></tr></table><ul>
+<h5>Example:</h5>
-Unary operators are used to do a simple operation to a single value.<p>
+<pre>
+ <i>; Emulate a conditional br instruction</i>
+ %Val = <a href="#i_cast">cast</a> bool %value to int
+ switch int %Val, label %truedest [int 0, label %falsedest ]
-There are two different unary operators: the '<a href="#i_not"><tt>not</tt></a>' instruction and the '<a href="#i_cast"><tt>cast</tt></a>' instruction.<p>
+ <i>; Emulate an unconditional br instruction</i>
+ switch uint 0, label %dest [ ]
+ <i>; Implement a jump table:</i>
+ switch uint %val, label %otherwise [ uint 0, label %onzero
+ uint 1, label %onone
+ uint 2, label %ontwo ]
+</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_not"><h4><hr size=0>'<tt>not</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = not <ty> <var> <i>; yields {ty}:result</i>
+ <result> = invoke [<a href="#callingconv">cconv</a>] <ptr to function ty> %<function ptr val>(<function args>)
+ to label <normal label> unwind label <exception label>
</pre>
<h5>Overview:</h5>
-The '<tt>not</tt>' instruction returns the <a href="#logical_integrals">logical</a> inverse of its operand.<p>
+
+<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>
<h5>Arguments:</h5>
-The single argument to '<tt>not</tt>' must be of of <a href="#t_integral">integral</a> type.<p>
+<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>'<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>
+
+ <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
+ 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>
+
+ <li>'<tt>normal label</tt>': the label reached when the called function
+ 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>
+
+</ol>
<h5>Semantics:</h5>
-The '<tt>not</tt>' instruction returns the <a href="#logical_integrals">logical</a> inverse of an <a href="#t_integral">integral</a> type.<p>
-Note that the '<tt>not</tt>' instruction is is not defined over to '<tt>bool</tt>' type. To invert a boolean value, the recommended method is to use:<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>
-<pre>
- <result> = xor bool true, <var> <i>; yields {bool}:result</i>
-</pre>
+<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>
<h5>Example:</h5>
<pre>
- %x = not int 1 <i>; {int}:x is now equal to 0</i>
- %x = not bool true <i>; {bool}:x is now equal to false</i>
+ %retval = invoke int %Test(int 15) to label %Continue
+ unwind label %TestCleanup <i>; {int}:retval set</i>
+ %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
+ unwind label %TestCleanup <i>; {int}:retval set</i>
</pre>
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_cast"><h4><hr size=0>'<tt>cast .. to</tt>' Instruction</h4><ul>
-
-<h1>TODO</h1>
-
-<a name="logical_integrals">
- Talk about what is considered true or false for integrals.
+<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
+ unwind
</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>
-<h5>Arguments:</h5>
+<h5>Semantics:</h5>
+<p>The '<tt>unwind</tt>' intrinsic 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>
+</div>
-<h5>Semantics:</h5>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
+Instruction</a> </div>
-<h5>Example:</h5>
+<div class="doc_text">
+
+<h5>Syntax:</h5>
<pre>
+ unreachable
</pre>
+<h5>Overview:</h5>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="binaryops">Binary Operations
-</b></font></td></tr></table><ul>
+<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>
-Binary operators are used to do most of the computation in a program. They require two operands, execute an operation on them, and produce a single value. The result value of a binary operator is not neccesarily the same type as its operands.<p>
+<h5>Semantics:</h5>
-There are several different binary operators:<p>
+<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
+</div>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_add"><h4><hr size=0>'<tt>add</tt>' Instruction</h4><ul>
+<!-- ======================================================================= -->
+<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, 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_packed">packed</a> data type.
+The result value of a binary operator is not
+necessarily 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>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+<pre> <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i>
</pre>
-
<h5>Overview:</h5>
-The '<tt>add</tt>' instruction returns the sum of its two operands.<p>
-
+<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
<h5>Arguments:</h5>
-The two arguments to the '<tt>add</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
-
+<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
+ This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-...<p>
-
+<p>The value produced is the integer or floating point sum of the two
+operands.</p>
<h5>Example:</h5>
-<pre>
- <result> = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
+<pre> <result> = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>sub</tt>' instruction returns the difference of its two
+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>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
+<h5>Semantics:</h5>
+<p>The value produced is the integer or floating point difference of
+the two operands.</p>
+<h5>Example:</h5>
+<pre> <result> = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
+ <result> = sub int 0, %val <i>; yields {int}:result = -%var</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<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 either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
+<h5>Semantics:</h5>
+<p>The value produced is the integer or floating point product of the
+two operands.</p>
+<p>There is no signed vs unsigned multiplication. The appropriate
+action is taken based on the type of the operand.</p>
+<h5>Example:</h5>
+<pre> <result> = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = div <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>div</tt>' instruction returns the quotient of its two
+operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
+<h5>Semantics:</h5>
+<p>The value produced is the integer or floating point quotient of the
+two operands.</p>
+<h5>Example:</h5>
+<pre> <result> = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = rem <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>rem</tt>' instruction returns the remainder from the
+division of its two operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
+<h5>Semantics:</h5>
+<p>This returns the <i>remainder</i> of a division (where the result
+has the same sign as the divisor), not the <i>modulus</i> (where the
+result has the same sign as the dividend) 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>.</p>
+<h5>Example:</h5>
+<pre> <result> = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
+Instructions</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = seteq <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+ <result> = setne <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+ <result> = setlt <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+ <result> = setgt <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+ <result> = setle <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+ <result> = setge <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
+value based on a comparison of their two operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
+be of <a href="#t_firstclass">first class</a> type (it is not possible
+to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
+or '<tt>void</tt>' values, etc...). Both arguments must have identical
+types.</p>
+<h5>Semantics:</h5>
+<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if both operands are equal.<br>
+The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if both operands are unequal.<br>
+The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is less than the second operand.<br>
+The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is greater than the second operand.<br>
+The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is less than or equal to the second operand.<br>
+The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is greater than or equal to the second
+operand.</p>
+<h5>Example:</h5>
+<pre> <result> = seteq int 4, 5 <i>; yields {bool}:result = false</i>
+ <result> = setne float 4, 5 <i>; yields {bool}:result = true</i>
+ <result> = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
+ <result> = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
+ <result> = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
+ <result> = setge sbyte 4, 5 <i>; yields {bool}:result = false</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, execute an operation on them,
+and produce a single value. The resulting value of the bitwise binary
+operators is always the same type as its first operand.</p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = and <ty> <var1>, <var2> <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>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>and</tt>' instruction must be <a
+ href="#t_integral">integral</a> 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 style="align: center">
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr>
+ <td>In0</td>
+ <td>In1</td>
+ <td>Out</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>1</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ </tbody>
+</table>
+</div>
+<h5>Example:</h5>
+<pre> <result> = and int 4, %var <i>; yields {int}:result = 4 & %var</i>
+ <result> = and int 15, 40 <i>; yields {int}:result = 8</i>
+ <result> = and int 4, 8 <i>; yields {int}:result = 0</i>
+</pre>
+</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> <var1>, <var2> <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>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>or</tt>' instruction must be <a
+ href="#t_integral">integral</a> 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 style="align: center">
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr>
+ <td>In0</td>
+ <td>In1</td>
+ <td>Out</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>0</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ </tbody>
+</table>
+</div>
+<h5>Example:</h5>
+<pre> <result> = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
+ <result> = or int 15, 40 <i>; yields {int}:result = 47</i>
+ <result> = or int 4, 8 <i>; yields {int}: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> <var1>, <var2> <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>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
+ href="#t_integral">integral</a> 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 style="align: center">
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr>
+ <td>In0</td>
+ <td>In1</td>
+ <td>Out</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>0</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>1</td>
+ <td>0</td>
+ </tr>
+ </tbody>
+</table>
+</div>
+<p> </p>
+<h5>Example:</h5>
+<pre> <result> = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
+ <result> = xor int 15, 40 <i>; yields {int}:result = 39</i>
+ <result> = xor int 4, 8 <i>; yields {int}:result = 12</i>
+ <result> = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
+</pre>
+</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> <var1>, ubyte <var2> <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>
+<h5>Arguments:</h5>
+<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
+ href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
+type.</p>
+<h5>Semantics:</h5>
+<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
+<h5>Example:</h5>
+<pre> <result> = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i>
+ <result> = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
+ <result> = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = shr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
+the right a specified number of bits.</p>
+<h5>Arguments:</h5>
+<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
+ href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
+type.</p>
+<h5>Semantics:</h5>
+<p>If the first argument is a <a href="#t_signed">signed</a> type, the
+most significant bit is duplicated in the newly free'd bit positions.
+If the first argument is unsigned, zero bits shall fill the empty
+positions.</p>
+<h5>Example:</h5>
+<pre> <result> = shr int 4, ubyte %var <i>; yields {int}:result = 4 >> %var</i>
+ <result> = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
+ <result> = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
+ <result> = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
+ <result> = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
+</pre>
+</div>
+
+<!-- ======================================================================= -->
+<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. This 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_subsubsection">
+ <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<pre>
+ <result> = extractelement <n x <ty>> <val>, uint <idx> <i>; yields <ty></i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>extractelement</tt>' instruction extracts a single scalar
+element from a packed 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_packed">packed</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 int> %vec, uint 0 <i>; yields int</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>, uint <idx> <i>; yields <n x <ty>></i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>insertelement</tt>' instruction inserts a scalar
+element into a packed 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_packed">packed</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 packed 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 int> %vec, int 1, uint 0 <i>; yields <4 x int></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>, <n x uint> <mask> <i>; yields <n 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 of the same type.
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
+with types that match each other and types that match the result of the
+instruction. The third argument is a shuffle mask, which has the same number
+of elements as the other vector type, but whose element type is always 'uint'.
+</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 registers 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 int> %v1, <4 x int> %v2,
+ <4 x uint> <uint 0, uint 4, uint 1, uint 5> <i>; yields <4 x int></i>
+ %result = shufflevector <4 x int> %v1, <4 x int> undef,
+ <4 x uint> <uint 0, uint 1, uint 2, uint 3> <i>; yields <4 x int></i> - Identity shuffle.
+</pre>
+</div>
+
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_vsetint">'<tt>vsetint</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre><result> = vsetint <op>, <n x <ty>> <var1>, <var2> <i>; yields <n x bool></i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>vsetint</tt>' instruction takes two integer vectors and
+returns a vector of boolean values representing, at each position, the
+result of the comparison between the values at that position in the
+two operands.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments to a '<tt>vsetint</tt>' instruction are a comparison
+operation and two value arguments. The value arguments must be of <a
+href="#t_integral">integral</a> <a href="#t_packed">packed</a> type,
+and they must have identical types. The operation argument must be
+one of <tt>eq</tt>, <tt>ne</tt>, <tt>slt</tt>, <tt>sgt</tt>,
+<tt>sle</tt>, <tt>sge</tt>, <tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>,
+<tt>uge</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a
+packed <tt>bool</tt> value with the same length as each operand.</p>
+
+<h5>Semantics:</h5>
+
+<p>The following table shows the semantics of '<tt>vsetint</tt>'. For
+each position of the result, the comparison is done on the
+corresponding positions of the two value arguments. Note that the
+signedness of the comparison depends on the comparison opcode and
+<i>not</i> on the signedness of the value operands. E.g., <tt>vsetint
+slt <4 x unsigned> %x, %y</tt> does an elementwise <i>signed</i>
+comparison of <tt>%x</tt> and <tt>%y</tt>.</p>
+
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr><th>Operation</th><th>Result is true iff</th><th>Comparison is</th></tr>
+ <tr><td><tt>eq</tt></td><td>var1 == var2</td><td>--</td></tr>
+ <tr><td><tt>ne</tt></td><td>var1 != var2</td><td>--</td></tr>
+ <tr><td><tt>slt</tt></td><td>var1 < var2</td><td>signed</td></tr>
+ <tr><td><tt>sgt</tt></td><td>var1 > var2</td><td>signed</td></tr>
+ <tr><td><tt>sle</tt></td><td>var1 <= var2</td><td>signed</td></tr>
+ <tr><td><tt>sge</tt></td><td>var1 >= var2</td><td>signed</td></tr>
+ <tr><td><tt>ult</tt></td><td>var1 < var2</td><td>unsigned</td></tr>
+ <tr><td><tt>ugt</tt></td><td>var1 > var2</td><td>unsigned</td></tr>
+ <tr><td><tt>ule</tt></td><td>var1 <= var2</td><td>unsigned</td></tr>
+ <tr><td><tt>uge</tt></td><td>var1 >= var2</td><td>unsigned</td></tr>
+ <tr><td><tt>true</tt></td><td>always</td><td>--</td></tr>
+ <tr><td><tt>false</tt></td><td>never</td><td>--</td></tr>
+ </tbody>
+</table>
+
+<h5>Example:</h5>
+<pre> <result> = vsetint eq <2 x int> <int 0, int 1>, <int 1, int 0> <i>; yields {<2 x bool>}:result = false, false</i>
+ <result> = vsetint ne <2 x int> <int 0, int 1>, <int 1, int 0> <i>; yields {<2 x bool>}:result = true, true</i>
+ <result> = vsetint slt <2 x int> <int 0, int 1>, <int 1, int 0> <i>; yields {<2 x bool>}:result = true, false</i>
+ <result> = vsetint sgt <2 x int> <int 0, int 1>, <int 1, int 0> <i>; yields {<2 x bool>}:result = false, true</i>
+ <result> = vsetint sle <2 x int> <int 0, int 1>, <int 1, int 0> <i>; yields {<2 x bool>}:result = true, false</i>
+ <result> = vsetint sge <2 x int> <int 0, int 1>, <int 1, int 0> <i>; yields {<2 x bool>}:result = false, true</i>
+</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_vsetfp">'<tt>vsetfp</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre><result> = vsetfp <op>, <n x <ty>> <var1>, <var2> <i>; yields <n x bool></i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>vsetfp</tt>' instruction takes two floating point vector
+arguments and returns a vector of boolean values representing, at each
+position, the result of the comparison between the values at that
+position in the two operands.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments to a '<tt>vsetfp</tt>' instruction are a comparison
+operation and two value arguments. The value arguments must be of <a
+href="t_floating">floating point</a> <a href="#t_packed">packed</a>
+type, and they must have identical types. The operation argument must
+be one of <tt>eq</tt>, <tt>ne</tt>, <tt>lt</tt>, <tt>gt</tt>,
+<tt>le</tt>, <tt>ge</tt>, <tt>oeq</tt>, <tt>one</tt>, <tt>olt</tt>,
+<tt>ogt</tt>, <tt>ole</tt>, <tt>oge</tt>, <tt>ueq</tt>, <tt>une</tt>,
+<tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>, <tt>uge</tt>, <tt>o</tt>,
+<tt>u</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a packed
+<tt>bool</tt> value with the same length as each operand.</p>
+
+<h5>Semantics:</h5>
+
+<p>The following table shows the semantics of '<tt>vsetfp</tt>' for
+floating point types. If either operand is a floating point Not a
+Number (NaN) value, the operation is unordered, and the value in the
+first column below is produced at that position. Otherwise, the
+operation is ordered, and the value in the second column is
+produced.</p>
+
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr><th>Operation</th><th>If unordered<th>Otherwise true iff</th></tr>
+ <tr><td><tt>eq</tt></td><td>undefined</td><td>var1 == var2</td></tr>
+ <tr><td><tt>ne</tt></td><td>undefined</td><td>var1 != var2</td></tr>
+ <tr><td><tt>lt</tt></td><td>undefined</td><td>var1 < var2</td></tr>
+ <tr><td><tt>gt</tt></td><td>undefined</td><td>var1 > var2</td></tr>
+ <tr><td><tt>le</tt></td><td>undefined</td><td>var1 <= var2</td></tr>
+ <tr><td><tt>ge</tt></td><td>undefined</td><td>var1 >= var2</td></tr>
+ <tr><td><tt>oeq</tt></td><td>false</td><td>var1 == var2</td></tr>
+ <tr><td><tt>one</tt></td><td>false</td><td>var1 != var2</td></tr>
+ <tr><td><tt>olt</tt></td><td>false</td><td>var1 < var2</td></tr>
+ <tr><td><tt>ogt</tt></td><td>false</td><td>var1 > var2</td></tr>
+ <tr><td><tt>ole</tt></td><td>false</td><td>var1 <= var2</td></tr>
+ <tr><td><tt>oge</tt></td><td>false</td><td>var1 >= var2</td></tr>
+ <tr><td><tt>ueq</tt></td><td>true</td><td>var1 == var2</td></tr>
+ <tr><td><tt>une</tt></td><td>true</td><td>var1 != var2</td></tr>
+ <tr><td><tt>ult</tt></td><td>true</td><td>var1 < var2</td></tr>
+ <tr><td><tt>ugt</tt></td><td>true</td><td>var1 > var2</td></tr>
+ <tr><td><tt>ule</tt></td><td>true</td><td>var1 <= var2</td></tr>
+ <tr><td><tt>uge</tt></td><td>true</td><td>var1 >= var2</td></tr>
+ <tr><td><tt>o</tt></td><td>false</td><td>always</td></tr>
+ <tr><td><tt>u</tt></td><td>true</td><td>never</td></tr>
+ <tr><td><tt>true</tt></td><td>true</td><td>always</td></tr>
+ <tr><td><tt>false</tt></td><td>false</td><td>never</td></tr>
+ </tbody>
+</table>
+
+<h5>Example:</h5>
+<pre> <result> = vsetfp eq <2 x float> <float 0.0, float 1.0>, <float 1.0, float 0.0> <i>; yields {<2 x bool>}:result = false, false</i>
+ <result> = vsetfp ne <2 x float> <float 0.0, float 1.0>, <float 1.0, float 0.0> <i>; yields {<2 x bool>}:result = true, true</i>
+ <result> = vsetfp lt <2 x float> <float 0.0, float 1.0>, <float 1.0, float 0.0> <i>; yields {<2 x bool>}:result = true, false</i>
+ <result> = vsetfp gt <2 x float> <float 0.0, float 1.0>, <float 1.0, float 0.0> <i>; yields {<2 x bool>}:result = false, true</i>
+ <result> = vsetfp le <2 x float> <float 0.0, float 1.0>, <float 1.0, float 0.0> <i>; yields {<2 x bool>}:result = true, false</i>
+ <result> = vsetfp ge <2 x float> <float 0.0, float 1.0>, <float 1.0, float 0.0> <i>; yields {<2 x bool>}:result = false, true</i>
+</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_vselect">'<tt>vselect</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<pre>
+ <result> = vselect <n x bool> <cond>, <n x <ty>> <val1>, <n x <ty>> <val2> <i>; yields <n x <ty>></i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>vselect</tt>' instruction chooses one value at each position
+of a vector based on a condition.
+</p>
+
+
+<h5>Arguments:</h5>
+
+<p>
+The '<tt>vselect</tt>' instruction requires a <a
+href="#t_packed">packed</a> <tt>bool</tt> value indicating the
+condition at each vector position, and two values of the same packed
+type. All three operands must have the same length. The type of the
+result is the same as the type of the two value operands.</p>
+
+<h5>Semantics:</h5>
+
+<p>
+At each position where the <tt>bool</tt> vector is true, that position
+of the result gets its value from the first value argument; otherwise,
+it gets its value from the second value argument.
+</p>
+
+<h5>Example:</h5>
+
+<pre>
+ %X = vselect bool <2 x bool> <bool true, bool false>, <2 x ubyte> <ubyte 17, ubyte 17>,
+ <2 x ubyte> <ubyte 42, ubyte 42> <i>; yields <2 x ubyte>:17, 42</i>
+</pre>
+</div>
+
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="memoryops">Memory Access 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>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<pre>
+ <result> = malloc <type>[, uint <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>malloc</tt>' instruction allocates memory from the system
+heap and returns a pointer to it.</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. If an 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.</p>
+
+<p>'<tt>type</tt>' must be a sized type.</p>
+
+<h5>Semantics:</h5>
+
+<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
+a pointer is returned.</p>
+
+<h5>Example:</h5>
+
+<pre>
+ %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
+
+ %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
+ %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
+ %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
+ %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i>
+ %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i>
+</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_free">'<tt>free</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<pre>
+ free <type> <value> <i>; yields {void}</i>
+</pre>
+
+<h5>Overview:</h5>
+
+<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>
+
+<h5>Semantics:</h5>
+
+<p>Access to the memory pointed to by the pointer is no longer defined
+after this instruction executes.</p>
+
+<h5>Example:</h5>
+
+<pre>
+ %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
+ free [4 x ubyte]* %array
+</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<pre>
+ <result> = alloca <type>[, uint <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>alloca</tt>' instruction allocates memory on the current
+stack frame of the procedure that is live until the current function
+returns to its caller.</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. If an 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.</p>
+
+<p>'<tt>type</tt>' may be any sized type.</p>
+
+<h5>Semantics:</h5>
+
+<p>Memory is allocated; a pointer is returned. '<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.</p>
+
+<h5>Example:</h5>
+
+<pre>
+ %ptr = alloca int <i>; yields {int*}:ptr</i>
+ %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
+ %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i>
+ %ptr = alloca int, align 1024 <i>; yields {int*}: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><br> <result> = volatile load <ty>* <pointer><br></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>
+<h5>Semantics:</h5>
+<p>The location of memory pointed to is loaded.</p>
+<h5>Examples:</h5>
+<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
+ <a
+ href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
+ %val = load int* %ptr <i>; yields {int}:val = int 3</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
+Instruction</a> </div>
+<h5>Syntax:</h5>
+<pre> store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i>
+ volatile store <ty> <value>, <ty>* <pointer> <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 in which to store it. The type of the '<tt><pointer></tt>'
+operand must be a pointer to the 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>
+<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.</p>
+<h5>Example:</h5>
+<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
+ <a
+ href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
+ %val = load int* %ptr <i>; yields {int}:val = int 3</i>
+</pre>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre>
+ <result> = getelementptr <ty>* <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.</p>
+
+<h5>Arguments:</h5>
+
+<p>This instruction takes a list of integer constants that indicate what
+elements of the aggregate object to index to. The actual types of the arguments
+provided depend on the type of the first pointer argument. The
+'<tt>getelementptr</tt>' instruction is used to index down through the type
+levels of a structure or to a specific index in an array. When indexing into a
+structure, only <tt>uint</tt>
+integer constants are allowed. When indexing into an array or pointer,
+<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
+
+<p>For example, let's consider a C code fragment and how it gets
+compiled to LLVM:</p>
+
+<pre>
+ struct RT {
+ char A;
+ int B[10][20];
+ char C;
+ };
+ struct ST {
+ int X;
+ double Y;
+ struct RT Z;
+ };
+
+ int *foo(struct ST *s) {
+ return &s[1].Z.B[5][13];
+ }
+</pre>
+
+<p>The LLVM code generated by the GCC frontend is:</p>
+
+<pre>
+ %RT = type { sbyte, [10 x [20 x int]], sbyte }
+ %ST = type { int, double, %RT }
+
+ implementation
+
+ int* %foo(%ST* %s) {
+ entry:
+ %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
+ ret int* %reg
+ }
+</pre>
+
+<h5>Semantics:</h5>
+
+<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
+on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
+and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
+<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
+types require <tt>uint</tt> <b>constants</b>.</p>
+
+<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>{ int, double, %RT
+}</tt>' type, a structure. The second index indexes into the third element of
+the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
+sbyte }</tt>' type, another structure. The third index indexes into the second
+element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
+array. The two dimensions of the array are subscripted into, yielding an
+'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
+to this element, thus computing a value of '<tt>int*</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>
+
+<pre>
+ int* %foo(%ST* %s) {
+ %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
+ %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
+ %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
+ %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
+ %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
+ ret int* %t5
+ }
+</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.
+The one exception for this rules is zero length arrays. These arrays are
+defined to be accessible as variable length arrays, which requires access
+beyond the zero'th element.</p>
+
+<h5>Example:</h5>
+
+<pre>
+ <i>; yields [12 x ubyte]*:aptr</i>
+ %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
+</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>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<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 are 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>
+<h5>Semantics:</h5>
+<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
+value specified by the parameter, depending on which basic block we
+came from in the last <a href="#terminators">terminator</a> instruction.</p>
+<h5>Example:</h5>
+<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_sub"><h4><hr size=0>'<tt>sub</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <result> = cast <ty> <value> to <ty2> <i>; yields ty2</i>
</pre>
<h5>Overview:</h5>
-The '<tt>sub</tt>' instruction returns the difference of its two operands.<p>
-Note that the '<tt>sub</tt>' instruction is the cannonical way the '<tt>neg</tt>' instruction is represented as well.<p>
+<p>
+The '<tt>cast</tt>' instruction is used as the primitive means to convert
+integers to floating point, change data type sizes, and break type safety (by
+casting pointers).
+</p>
+
<h5>Arguments:</h5>
-The two arguments to the '<tt>sub</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
+
+<p>
+The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
+class value, and a type to cast it to, which must also be a <a
+href="#t_firstclass">first class</a> type.
+</p>
<h5>Semantics:</h5>
-...<p>
+
+<p>
+This instruction follows the C rules for explicit casts when determining how the
+data being cast must change to fit in its new container.
+</p>
+
+<p>
+When casting to bool, any value that would be considered true in the context of
+a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
+all else are '<tt>false</tt>'.
+</p>
+
+<p>
+When extending an integral value from a type of one signness to another (for
+example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
+<b>source</b> value is signed, and zero-extended if the source value is
+unsigned. <tt>bool</tt> values are always zero extended into either zero or
+one.
+</p>
<h5>Example:</h5>
+
<pre>
- <result> = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
- <result> = sub int 0, %val <i>; yields {int}:result = -%var</i>
+ %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
+ %Y = cast int 123 to bool <i>; yields bool:true</i>
</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_mul"><h4><hr size=0>'<tt>mul</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_select">'<tt>select</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <result> = select bool <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
</pre>
<h5>Overview:</h5>
-The '<tt>mul</tt>' instruction returns the product of its two operands.<p>
+
+<p>
+The '<tt>select</tt>' instruction is used to choose one value based on a
+condition, without branching.
+</p>
+
<h5>Arguments:</h5>
-The two arguments to the '<tt>mul</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
+
+<p>
+The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
+</p>
<h5>Semantics:</h5>
-...<p>
-There is no signed vs unsigned multiplication. The appropriate action is taken based on the type of the operand. <p>
+<p>
+If the boolean condition evaluates to true, the instruction returns the first
+value argument; otherwise, it returns the second value argument.
+</p>
<h5>Example:</h5>
+
<pre>
- <result> = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
+ %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_div"><h4><hr size=0>'<tt>div</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_call">'<tt>call</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = div <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <result> = [tail] call [<a href="#callingconv">cconv</a>] <ty>* <fnptrval>(<param list>)
</pre>
<h5>Overview:</h5>
-The '<tt>div</tt>' instruction returns the quotient of its two operands.<p>
+
+<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
<h5>Arguments:</h5>
-The two arguments to the '<tt>div</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
+
+<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.
+ </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.
+ </li>
+ <li>
+ <p>'<tt>ty</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>
+</ol>
<h5>Semantics:</h5>
-...<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. This is a simpler case of
+the <a href="#i_invoke">invoke</a> instruction.</p>
<h5>Example:</h5>
+
<pre>
- <result> = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
+ %retval = call int %test(int %argc)
+ call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
+ %X = tail call int %foo()
+ %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_rem"><h4><hr size=0>'<tt>rem</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = rem <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <resultval> = va_arg <va_list*> <arglist>, <argty>
</pre>
<h5>Overview:</h5>
-The '<tt>rem</tt>' instruction returns the remainder from the division of its two operands.<p>
+
+<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>
<h5>Arguments:</h5>
-The two arguments to the '<tt>rem</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<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. Again, the
+actual type of <tt>va_list</tt> is target specific.</p>
<h5>Semantics:</h5>
-TODO: remainder or modulus?<p>
-...<p>
-<h5>Example:</h5>
-<pre>
- <result> = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
-</pre>
+<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>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_setcc"><h4><hr size=0>'<tt>set<i>cc</i></tt>' Instructions</h4><ul>
+<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>Syntax:</h5>
-<pre>
- <result> = seteq <ty> <var1>, <var2> <i>; yields {bool}:result</i>
- <result> = setne <ty> <var1>, <var2> <i>; yields {bool}:result</i>
- <result> = setlt <ty> <var1>, <var2> <i>; yields {bool}:result</i>
- <result> = setgt <ty> <var1>, <var2> <i>; yields {bool}:result</i>
- <result> = setle <ty> <var1>, <var2> <i>; yields {bool}:result</i>
- <result> = setge <ty> <var1>, <var2> <i>; yields {bool}:result</i>
-</pre>
+<h5>Example:</h5>
-<h5>Overview:</h5>
-The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean value based on a comparison of their two operands.<p>
+<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
-<h5>Arguments:</h5>
-The two arguments to the '<tt>set<i>cc</i></tt>' instructions must be of <a href="#t_firstclass">first class</a> or <a href="#t_derived">derived</a> type (it is not possible to compare '<tt>label</tt>'s or '<tt>void</tt>' values). Both arguments must have identical types.<p>
+</div>
-The '<tt>setlt</tt>', '<tt>setgt</tt>', '<tt>setle</tt>', and '<tt>setge</tt>' instructions do not operate on '<tt>bool</tt>' typed arguments.<p>
+<!-- *********************************************************************** -->
+<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
+<!-- *********************************************************************** -->
-<h5>Semantics:</h5>
-The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if both operands are equal.<br>
-The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if both operands are unequal.<br>
-The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if the first operand is less than the second operand.<br>
-The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if the first operand is greater than the second operand.<br>
-The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if the first operand is less than or equal to the second operand.<br>
-The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if the first operand is greater than or equal to the second operand.<p>
+<div class="doc_text">
-<h5>Example:</h5>
-<pre>
- <result> = seteq int 4, 5 <i>; yields {bool}:result = false</i>
- <result> = setne float 4, 5 <i>; yields {bool}:result = true</i>
- <result> = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
- <result> = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
- <result> = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
- <result> = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
-</pre>
+<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 instructions represent an extension mechanism for
+the LLVM language that does not require changing all of the transformations in
+LLVM to add to the language (or the bytecode 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, functions may not be named
+this. 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 that they all be documented here if any are added.</p>
+<p>To learn how to add an intrinsic function, please see the <a
+href="ExtendingLLVM.html">Extending LLVM Guide</a>.
+</p>
+
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="bitwiseops">Bitwise Binary Operations
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="int_varargs">Variable Argument Handling Intrinsics</a>
+</div>
-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, execute an operation on them, and produce a single value. The resulting value of the bitwise binary operators is always the same type as its first operand.<p>
+<div class="doc_text">
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_and"><h4><hr size=0>'<tt>and</tt>' Instruction</h4><ul>
+<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 intrinsics with any 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>
-<h5>Syntax:</h5>
<pre>
- <result> = and <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+int %test(int %X, ...) {
+ ; Initialize variable argument processing
+ %ap = alloca sbyte*
+ call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
+
+ ; Read a single integer argument
+ %tmp = va_arg sbyte** %ap, int
+
+ ; Demonstrate usage of llvm.va_copy and llvm.va_end
+ %aq = alloca sbyte*
+ call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap)
+ call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
+
+ ; Stop processing of arguments.
+ call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
+ ret int %tmp
+}
</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> declare void %llvm.va_start(<va_list>* <arglist>)<br></pre>
<h5>Overview:</h5>
-The '<tt>and</tt>' instruction returns the bitwise logical and of its two operands.<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>
-The two arguments to the '<tt>and</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_bool"><tt>bool</tt></a> values. Both arguments must have identical types.<p>
+<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
<h5>Semantics:</h5>
-...<p>
+<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 the argument points to, 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, the compiler can figure that out.</p>
-<h5>Example:</h5>
-<pre>
- <result> = and int 4, %var <i>; yields {int}:result = 4 & %var</i>
- <result> = and int 15, 40 <i>; yields {int}:result = 8</i>
- <result> = and int 4, 8 <i>; yields {int}:result = 0</i>
-</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> declare void %llvm.va_end(<va_list*> <arglist>)<br></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="#i_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 <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>.
+Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
+ href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
+with calls to <tt>llvm.va_end</tt>.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_or"><h4><hr size=0>'<tt>or</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = or <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ declare void %llvm.va_copy(<va_list>* <destarglist>,
+ <va_list>* <srcarglist>)
</pre>
<h5>Overview:</h5>
-The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its two operands.<p>
+
+<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
+the source argument list to the destination argument list.</p>
<h5>Arguments:</h5>
-The two arguments to the '<tt>or</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_bool"><tt>bool</tt></a> values. Both arguments must have identical types.<p>
+
+<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>
<h5>Semantics:</h5>
-...<p>
+<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 list. This intrinsic is necessary
+because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
+arbitrarily complex and require memory allocation, for example.</p>
-<h5>Example:</h5>
-<pre>
- <result> = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
- <result> = or int 15, 40 <i>; yields {int}:result = 47</i>
- <result> = or int 4, 8 <i>; yields {int}:result = 12</i>
-</pre>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+LLVM support for <a href="GarbageCollection.html">Accurate Garbage
+Collection</a> requires the implementation and generation of these intrinsics.
+These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
+stack</a>, as well as garbage collector implementations that require <a
+href="#i_gcread">read</a> and <a href="#i_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>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_xor"><h4><hr size=0>'<tt>xor</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = xor <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ declare void %llvm.gcroot(<ty>** %ptrloc, <ty2>* %metadata)
</pre>
<h5>Overview:</h5>
-The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of its two operands.<p>
+
+<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>
<h5>Arguments:</h5>
-The two arguments to the '<tt>xor</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_bool"><tt>bool</tt></a> values. Both arguments must have identical types.<p>
+<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>
<h5>Semantics:</h5>
-...<p>
+<p>At runtime, a call to this intrinsics 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.
+</p>
-<h5>Example:</h5>
-<pre>
- <result> = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
- <result> = xor int 15, 40 <i>; yields {int}:result = 39</i>
- <result> = xor int 4, 8 <i>; yields {int}:result = 12</i>
-</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_shl"><h4><hr size=0>'<tt>shl</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = shl <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+ declare sbyte* %llvm.gcread(sbyte* %ObjPtr, sbyte** %Ptr)
</pre>
<h5>Overview:</h5>
-The '<tt>shl</tt>' instruction returns the first operand shifted to the left a specified number of bits.
+
+<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
+locations, allowing garbage collector implementations that require read
+barriers.</p>
<h5>Arguments:</h5>
-The first argument to the '<tt>shl</tt>' instruction must be an <a href="#t_integral">integral</a> type. The second argument must be an '<tt>ubyte</tt>' type.<p>
+
+<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>
<h5>Semantics:</h5>
-... 0 bits are shifted into the emptied bit positions...<p>
+<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.</p>
-<h5>Example:</h5>
-<pre>
- <result> = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i>
- <result> = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
- <result> = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
-</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_shr"><h4><hr size=0>'<tt>shr</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = shr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+ declare void %llvm.gcwrite(sbyte* %P1, sbyte* %Obj, sbyte** %P2)
</pre>
<h5>Overview:</h5>
-The '<tt>shr</tt>' instruction returns the first operand shifted to the right a specified number of bits.
+
+<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>
<h5>Arguments:</h5>
-The first argument to the '<tt>shr</tt>' instruction must be an <a href="#t_integral">integral</a> type. The second argument must be an '<tt>ubyte</tt>' type.<p>
-<h5>Semantics:</h5>
-... if the first argument is a <a href="#t_signed">signed</a> type, the most significant bit is duplicated in the newly free'd bit positions. If the first argument is unsigned, zeros shall fill the empty positions...<p>
+<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>
-<h5>Example:</h5>
-<pre>
- <result> = shr int 4, ubyte %var <i>; yields {int}:result = 4 >> %var</i>
- <result> = shr int 4, ubyte 1 <i>; yields {int}:result = 2</i>
- <result> = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
- <result> = shr int 4, ubyte 3 <i>; yields {int}:result = 0</i>
-</pre>
+<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.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="memoryops">Memory Access Operations
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="int_codegen">Code Generator Intrinsics</a>
+</div>
-Accessing memory in SSA form is, well, sticky at best. This section describes how to read and write memory in LLVM.<p>
+<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>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_malloc"><h4><hr size=0>'<tt>malloc</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = malloc <type> <i>; yields { type *}:result</i>
- <result> = malloc [<type>], uint <NumElements> <i>; yields {[type] *}:result</i>
+ declare sbyte *%llvm.returnaddress(uint <level>)
</pre>
<h5>Overview:</h5>
-The '<tt>malloc</tt>' instruction allocates memory from the system heap and returns a pointer to it.<p>
-<h5>Arguments:</h5>
+<p>
+The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
+indicating the return address of the current function or one of its callers.
+</p>
-There are two forms of the '<tt>malloc</tt>' instruction, one for allocating a variable of a fixed type, and one for allocating an array. The array form is used to allocate an array, where the upper bound is not known until run time. If the upper bound is known at compile time, it is recommended that the first form be used with a <a href="#t_array_fixed">sized array type</a>.<p>
+<h5>Arguments:</h5>
-'<tt>type</tt>' may be any type except for a <a href="#t_array_unsized">unsized array type</a>.<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>
-Memory is allocated, a pointer is returned.<p>
-<h5>Example:</h5>
-<pre>
- %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
+<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>
- %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
- %array1 = malloc [ubyte], uint 4 <i>; yields {[ubyte]*}:array1</i>
- %array2 = malloc [ubyte], uint %size <i>; yields {[ubyte]*}:array2</i>
-</pre>
+<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>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_free"><h4><hr size=0>'<tt>free</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- free <type> <value> <i>; yields {void}</i>
+ declare sbyte *%llvm.frameaddress(uint <level>)
</pre>
-
<h5>Overview:</h5>
-The '<tt>free</tt>' instruction returns memory back to the unused memory heap, to be reallocated in the future.<p>
+<p>
+The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
+pointer value for the specified stack frame.
+</p>
<h5>Arguments:</h5>
-'<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 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>
-Memory is available for use after this point. The contents of the '<tt>value</tt>' pointer are undefined after this instruction.<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>
-<h5>Example:</h5>
-<pre>
- %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
- free [4 x ubyte]* %array
-</pre>
-
+<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>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_alloca"><h4><hr size=0>'<tt>alloca</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = alloca <type> <i>; yields {type*}:result</i>
- <result> = alloca [<type>], uint <NumElements> <i>; yields {[type] *}:result</i>
+ declare sbyte *%llvm.stacksave()
</pre>
<h5>Overview:</h5>
-The '<tt>alloca</tt>' instruction allocates memory on the current stack frame of the procedure that is live as long as the method does not return.<p>
+<p>
+The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
+the function stack, for use with <a href="#i_stackrestore">
+<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
+features like scoped automatic variable sized arrays in C99.
+</p>
-<h5>Arguments:</h5>
-There are two forms of the '<tt>alloca</tt>' instruction, one for allocating a variable of a fixed type, and one for allocating an array. The array form is used to allocate an array, where the upper bound is not known until run time. If the upper bound is known at compile time, it is recommended that the first form be used with a <a href="#t_array_fixed">sized array type</a>.<p>
+<h5>Semantics:</h5>
-'<tt>type</tt>' may be any type except for a <a href="#t_array_unsized">unsized array type</a>.<p>
+<p>
+This intrinsic returns a opaque pointer value that can be passed to <a
+href="#i_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>
-Note that a virtual machine may generate more efficient native code for a method if all of the fixed size '<tt>alloca</tt>' instructions live in the first basic block of that method.
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
+</div>
-<h5>Semantics:</h5>
-Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d memory is automatically released when the method returns. The '<tt>alloca</tt>' utility is how variable spills shall be implemented.<p>
+<div class="doc_text">
-<h5>Example:</h5>
+<h5>Syntax:</h5>
<pre>
- %ptr = alloca int <i>; yields {int*}:ptr</i>
- %ptr = alloca [int], uint 4 <i>; yields {[int]*}:ptr</i>
+ declare void %llvm.stackrestore(sbyte* %ptr)
</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="#llvm.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="#i_stacksave"><tt>llvm.stacksave</tt></a>.
+</p>
+
+</div>
+
<!-- _______________________________________________________________________ -->
-</ul><a name="i_load"><h4><hr size=0>'<tt>load</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = load <ty>* <pointer> <i>; yields {ty}:result</i>
- <result> = load <ty>* <arrayptr>, uint <idx> <i>; yields {ty}:result</i>
+ declare void %llvm.prefetch(sbyte * <address>,
+ uint <rw>, uint <locality>)
</pre>
<h5>Overview:</h5>
-The '<tt>load</tt>' instruction is used to read from memory.<p>
-<h5>Arguments:</h5>
-There are two forms of the '<tt>load</tt>' instruction: one for reading from a general pointer, and one for reading from a pointer to an array.<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>
-In the first form, '<tt><ty></tt>' may be any pointer type. If it is a pointer to an array, the first (zeroth) element is read from). In the second form, '<tt><ty></tt>' must be a pointer to an array. No bounds checking is performed on array reads.<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>
<h5>Semantics:</h5>
-...
-
-<h5>Examples:</h5>
-<pre>
- %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
- <a href="#i_store">store</a> int* %ptr, int 3 <i>; yields {void}</i>
- %val = load int* %ptr <i>; yields {int}:val = int 3</i>
-
- %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
- <a href="#i_store">store</a> [4 x ubyte]* %array,
- uint 4, ubyte 124
- %val = load [4 x ubyte]* %array, uint 4 <i>; yields {ubyte}:val = ubyte 124</i>
-
-</pre>
-
+<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>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_store"><h4><hr size=0>'<tt>store</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- store <ty>* <pointer>, <ty> <value> <i>; yields {void}</i>
- store <ty>* <arrayptr>, uint <idx>, <ty> <value> <i>; yields {void}</i>
+ declare void %llvm.pcmarker( uint <id> )
</pre>
<h5>Overview:</h5>
-The '<tt>store</tt>' instruction is used to write to memory.<p>
-<h5>Arguments:</h5>
-There are two forms of the '<tt>store</tt>' instruction: one for writing through a general pointer, and one for writing through a pointer to an array.<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>
-In the first form, '<tt><ty></tt>' may be any pointer type. If it is a pointer to an array, the first (zeroth) element is writen to). In the second form, '<tt><ty></tt>' must be a pointer to an array. No bounds checking is performed on array writes.<p>
+<h5>Arguments:</h5>
+<p>
+<tt>id</tt> is a numerical id identifying the marker.
+</p>
<h5>Semantics:</h5>
-...
-
-<h5>Example:</h5>
-<pre>
- %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
- store int* %ptr, int 3 <i>; yields {void}</i>
- %val = <a href="#i_load">load</a> int* %ptr <i>; yields {int}:val = int 3</i>
-
- %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
- store [4 x ubyte]* %array,
- uint 4, ubyte 124
- %val = <a href="#i_load">load</a> [4 x ubyte]* %array, uint 4 <i>; yields {ubyte}:val = ubyte 124</i>
-</pre>
-
+<p>
+This intrinsic does not modify the behavior of the program. Backends that do not
+support this intrinisic may ignore it.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_getfieldptr"><h4><hr size=0>'<tt>getfieldptr</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
-
+ declare ulong %llvm.readcyclecounter( )
</pre>
<h5>Overview:</h5>
-getfield takes a structure pointer, and an unsigned byte. It returns a pointer to the specified element, of the correct type. At the implementation level, this would be compiled down to an addition of a constant int.
-
-<h5>Arguments:</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>
<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>
-<h5>Example:</h5>
-<pre>
-
-</pre>
-
-
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="otherops">Other Operations
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="int_libc">Standard C Library Intrinsics</a>
+</div>
-The instructions in this catagory are the "miscellaneous" functions, that defy better classification.<p>
+<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>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_call"><h4><hr size=0>'<tt>call</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
-
+ declare void %llvm.memcpy.i32(sbyte* <dest>, sbyte* <src>,
+ uint <len>, uint <align>)
+ declare void %llvm.memcpy.i64(sbyte* <dest>, sbyte* <src>,
+ ulong <len>, uint <align>)
</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>
+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>
+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>
+</div>
-<h5>Example:</h5>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
<pre>
- %retval = call int %test(int %argc)
+ declare void %llvm.memmove.i32(sbyte* <dest>, sbyte* <src>,
+ uint <len>, uint <align>)
+ declare void %llvm.memmove.i64(sbyte* <dest>, sbyte* <src>,
+ ulong <len>, uint <align>)
</pre>
+<h5>Overview:</h5>
-<!-- _______________________________________________________________________ --></ul><a name="i_icall"><h3><hr size=0>'<tt>icall</tt>' Instruction</h3><ul>
+<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.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
+</p>
-Indirect calls are desperately needed to implement virtual function tables (C++, java) and function pointers (C, C++, ...).<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>
-A new instruction <tt>icall</tt> or similar should be introduced to represent an indirect call.<p>
+<h5>Arguments:</h5>
-Example:
-<pre>
- %retval = icall int %funcptr(int %arg1) <i>; yields {int}:%retval</i>
-</pre>
+<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>
+
+<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>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_phi"><h4><hr size=0>'<tt>phi</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
+ declare void %llvm.memset.i32(sbyte* <dest>, ubyte <val>,
+ uint <len>, uint <align>)
+ declare void %llvm.memset.i64(sbyte* <dest>, ubyte <val>,
+ ulong <len>, uint <align>)
</pre>
<h5>Overview:</h5>
+<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>
<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>
+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>
+</div>
-<h5>Example:</h5>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
<pre>
+ declare bool %llvm.isunordered.f32(float Val1, float Val2)
+ declare bool %llvm.isunordered.f64(double Val1, double Val2)
</pre>
+<h5>Overview:</h5>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="builtinfunc">Builtin Functions
-</b></font></td></tr></table><ul>
+<p>
+The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
+specified floating point values is a NAN.
+</p>
-<b>Notice:</b> Preliminary idea!<p>
+<h5>Arguments:</h5>
-Builtin functions are very similar to normal functions, except they are defined by the implementation. Invocations of these functions are very similar to method invocations, except that the syntax is a little less verbose.<p>
+<p>
+The arguments are floating point numbers of the same type.
+</p>
-Builtin functions are useful to implement semi-high level ideas like a '<tt>min</tt>' or '<tt>max</tt>' operation that can have important properties when doing program analysis. For example:
+<h5>Semantics:</h5>
-<ul>
-<li>Some optimizations can make use of identities defined over the functions,
- for example a parrallelizing compiler could make use of '<tt>min</tt>'
- identities to parrellelize a loop.
-<li>Builtin functions would have polymorphic types, where normal method calls
- may only have a single type.
-<li>Builtin functions would be known to not have side effects, simplifying
- analysis over straight method calls.
-<li>The syntax of the builtin are cleaner than the syntax of the
- '<a href="#i_call"><tt>call</tt></a>' instruction (very minor point).
-</ul>
+<p>
+If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
+false.
+</p>
+</div>
-Because these invocations are explicit in the representation, the runtime can choose to implement these builtin functions any way that they want, including:
-<ul>
-<li>Inlining the code directly into the invocation
-<li>Implementing the functions in some sort of Runtime class, convert invocation
- to a standard method call.
-<li>Implementing the functions in some sort of Runtime class, and perform
- standard inlining optimizations on it.
-</ul>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
+</div>
-Note that these builtins do not use quoted identifiers: the name of the builtin effectively becomes an identifier in the language.<p>
+<div class="doc_text">
-Example:
+<h5>Syntax:</h5>
<pre>
- ; Example of a normal method call
- %maximum = call int %maximum(int %arg1, int %arg2) <i>; yields {int}:%maximum</i>
+ declare double %llvm.sqrt.f32(float Val)
+ declare double %llvm.sqrt.f64(double Val)
+</pre>
- ; Examples of potential builtin functions
- %max = max(int %arg1, int %arg2) <i>; yields {int}:%max</i>
- %min = min(int %arg1, int %arg2) <i>; yields {int}:%min</i>
- %sin = sin(double %arg) <i>; yields {double}:%sin</i>
- %cos = cos(double %arg) <i>; yields {double}:%cos</i>
+<h5>Overview:</h5>
- ; Show that builtin's are polymorphic, like instructions
- %max = max(float %arg1, float %arg2) <i>; yields {float}:%max</i>
- %cos = cos(float %arg) <i>; yields {float}:%cos</i>
-</pre>
+<p>
+The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
+returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
+<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
+negative numbers (which allows for better optimization).
+</p>
+
+<h5>Arguments:</h5>
-The '<tt>maximum</tt>' vs '<tt>max</tt>' example illustrates the difference in calling semantics between a '<a href="#i_call"><tt>call</tt></a>' instruction and a builtin function invocation. Notice that the '<tt>maximum</tt>' example assumes that the method is defined local to the caller.<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 positive
+floating point number.
+</p>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_manip">Bit Manipulation Intrinsics</a>
+</div>
-<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="todo">TODO List
-</b></font></td></tr></table><ul>
-<!-- *********************************************************************** -->
+<div class="doc_text">
+<p>
+LLVM provides intrinsics for a few important bit manipulation operations.
+These allow efficient code generation for some algorithms.
+</p>
-This list of random topics includes things that will <b>need</b> to be addressed before the llvm may be used to implement a java like langauge. Right now, it is pretty much useless for any language, given to unavailable of structure types<p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="synchronization"><h3><hr size=0>Synchronization Instructions</h3><ul>
+<div class="doc_subsubsection">
+ <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
+</div>
-We will need some type of synchronization instructions to be able to implement stuff in Java well. The way I currently envision doing this is to introduce a '<tt>lock</tt>' type, and then add two (builtin or instructions) operations to lock and unlock the lock.<p>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre>
+ declare ushort %llvm.bswap.i16(ushort <id>)
+ declare uint %llvm.bswap.i32(uint <id>)
+ declare ulong %llvm.bswap.i64(ulong <id>)
+</pre>
-<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="extensions">Possible Extensions
-</b></font></td></tr></table><ul>
-<!-- *********************************************************************** -->
+<h5>Overview:</h5>
-These extensions are distinct from the TODO list, as they are mostly "interesting" ideas that could be implemented in the future by someone so motivated. They are not directly required to get <a href="#rw_java">Java</a> like languages working.<p>
+<p>
+The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
+64 bit quantity. These are useful for performing operations on data that is not
+in the target's native byte order.
+</p>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_tailcall"><h3><hr size=0>'<tt>tailcall</tt>' Instruction</h3><ul>
+<h5>Semantics:</h5>
-This could be useful. Who knows. '.net' does it, but is the optimization really worth the extra hassle? Using strong typing would make this trivial to implement and a runtime could always callback to using downconverting this to a normal '<a href="#i_call"><tt>call</tt></a>' instruction.<p>
+<p>
+The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low
+byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic
+returns a uint value that has the four bytes of the input uint swapped, so that
+if the input bytes are numbered 0, 1, 2, 3 then the returned uint will have its
+bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt> intrinsic extends this concept
+to 64 bits.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="globalvars"><h3><hr size=0>Global Variables</h3><ul>
+<div class="doc_subsubsection">
+ <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
+</div>
-In order to represent programs written in languages like C, we need to be able to support variables at the module (global) scope. Perhaps they should be written outside of the module definition even. Maybe global functions should be handled like this as well.<p>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre>
+ declare ubyte %llvm.ctpop.i8 (ubyte <src>)
+ declare ushort %llvm.ctpop.i16(ushort <src>)
+ declare uint %llvm.ctpop.i32(uint <src>)
+ declare ulong %llvm.ctpop.i64(ulong <src>)
+</pre>
-<!-- _______________________________________________________________________ -->
-</ul><a name="explicitparrellelism"><h3><hr size=0>Explicit Parrellelism</h3><ul>
+<h5>Overview:</h5>
-With the rise of massively parrellel architectures (like <a href="#rw_ia64">the IA64 architecture</a>, multithreaded CPU cores, and SIMD data sets) it is becoming increasingly more important to extract all of the ILP from a code stream possible. It would be interesting to research encoding methods that can explicitly represent this. One straightforward way to do this would be to introduce a "stop" instruction that is equilivent to the IA64 stop bit.<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
+unsigned integer type. The return type must match the argument type.
+</p>
-<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="related">Related Work
-</b></font></td></tr></table><ul>
-<!-- *********************************************************************** -->
+<h5>Semantics:</h5>
+
+<p>
+The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
+</p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
+</div>
-Codesigned virtual machines.<p>
+<div class="doc_text">
-<dl>
-<a name="rw_safetsa">
-<dt>SafeTSA
-<DD>Description here<p>
+<h5>Syntax:</h5>
+<pre>
+ declare ubyte %llvm.ctlz.i8 (ubyte <src>)
+ declare ushort %llvm.ctlz.i16(ushort <src>)
+ declare uint %llvm.ctlz.i32(uint <src>)
+ declare ulong %llvm.ctlz.i64(ulong <src>)
+</pre>
+
+<h5>Overview:</h5>
-<a name="rw_java">
-<dt><a href="http://www.javasoft.com">Java</a>
-<DD>Desciption here<p>
+<p>
+The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
+leading zeros in a variable.
+</p>
-<a name="rw_net">
-<dt><a href="http://www.microsoft.com/net">Microsoft .net</a>
-<DD>Desciption here<p>
+<h5>Arguments:</h5>
-<a name="rw_gccrtl">
-<dt><a href="http://www.math.umn.edu/systems_guide/gcc-2.95.1/gcc_15.html">GNU RTL Intermediate Representation</a>
-<DD>Desciption here<p>
+<p>
+The only argument is the value to be counted. The argument may be of any
+unsigned integer type. The return type must match the argument type.
+</p>
-<a name="rw_ia64">
-<dt><a href="http://developer.intel.com/design/ia-64/index.htm">IA64 Architecture & Instruction Set</a>
-<DD>Desciption here<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(int 2) = 30</tt>.
+</p>
+</div>
-<a name="rw_mmix">
-<dt><a href="http://www-cs-faculty.stanford.edu/~knuth/mmix-news.html">MMIX Instruction Set</a>
-<DD>Desciption here<p>
-<a name="rw_stroustrup">
-<dt><a href="http://www.research.att.com/~bs/devXinterview.html">"Interview With Bjarne Stroustrup"</a>
-<DD>This interview influenced the design and thought process behind LLVM in several ways, most notably the way that derived types are written in text format. See the question that starts with "you defined the C declarator syntax as an experiment that failed".<p>
-</dl>
<!-- _______________________________________________________________________ -->
-</ul><a name="rw_vectorization"><h3><hr size=0>Vectorized Architectures</h3><ul>
+<div class="doc_subsubsection">
+ <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
+</div>
-<dl>
-<a name="rw_intel_simd">
-<dt>Intel MMX, MMX2, SSE, SSE2
-<DD>Description here<p>
+<div class="doc_text">
-<a name="rw_amd_simd">
-<dt><a href="http://www.nondot.org/~sabre/os/H1ChipFeatures/3DNow!TechnologyManual.pdf">AMD 3Dnow!, 3Dnow! 2</a>
-<DD>Desciption here<p>
+<h5>Syntax:</h5>
+<pre>
+ declare ubyte %llvm.cttz.i8 (ubyte <src>)
+ declare ushort %llvm.cttz.i16(ushort <src>)
+ declare uint %llvm.cttz.i32(uint <src>)
+ declare ulong %llvm.cttz.i64(ulong <src>)
+</pre>
-<a name="rw_sun_simd">
-<dt><a href="http://www.nondot.org/~sabre/os/H1ChipFeatures/VISInstructionSetUsersManual.pdf">Sun VIS ISA</a>
-<DD>Desciption here<p>
+<h5>Overview:</h5>
+<p>
+The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
+trailing zeros.
+</p>
-</dl>
+<h5>Arguments:</h5>
-more...
+<p>
+The only argument is the value to be counted. The argument may be of any
+unsigned integer type. The return type must match the argument type.
+</p>
-<!-- *********************************************************************** -->
-</ul>
-<!-- *********************************************************************** -->
+<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_subsection">
+ <a name="int_debugger">Debugger Intrinsics</a>
+</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>
+
+<!-- *********************************************************************** -->
<hr>
-<font size=-1>
-<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
-<!-- Created: Tue Jan 23 15:19:28 CST 2001 -->
-<!-- hhmts start -->
-Last modified: Thu May 31 17:36:39 CDT 2001
-<!-- hhmts end -->
-</font>
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+<address>
+ <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
+ src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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+ src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
+
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
+ <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
+ Last modified: $Date$
+</address>
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