The LLVM code representation is designed to be used in three -different forms: as an in-memory compiler IR, as an on-disk bytecode +different forms: as an in-memory compiler IR, as an on-disk bitcode representation (suitable for fast loading by a Just-In-Time compiler), and as a human readable assembly language representation. This allows LLVM to provide a powerful intermediate representation for efficient @@ -250,19 +271,22 @@ 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:
+...because the definition of %x 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 +the optimizer before it outputs bitcode. The violations pointed out by the verifier pass indicate bugs in transformation passes or input to the parser.
+LLVM uses three different forms of identifiers, for different -purposes:
+LLVM identifiers come in two basic types: global and local. Global + identifiers (functions, global variables) begin with the @ character. Local + identifiers (register names, types) begin with the % character. Additionally, + there are three different formats for identifiers, for different purposes:
LLVM requires that values start with a '%' sign for two reasons: Compilers +
LLVM requires that values start with a prefix for two reasons: Compilers don't need to worry about name clashes with reserved words, and the set of reserved words may be expanded in the future without penalty. Additionally, unnamed identifiers allow a compiler to quickly come up with a temporary @@ -301,30 +327,36 @@ languages. There are keywords for different opcodes 'ret', etc...), for primitive type names ('void', 'i32', etc...), and others. These reserved words cannot conflict with variable names, because -none of them start with a '%' character.
+none of them start with a prefix character ('%' or '@').Here is an example of LLVM code to multiply the integer variable '%X' by 8:
The easy way:
+After strength reduction:
+And the hard way:
+- add i32 %X, %X ; yields {i32}:%0 - add i32 %0, %0 ; yields {i32}:%1 - %result = add i32 %1, %1 +add i32 %X, %X ; yields {i32}:%0 +add i32 %0, %0 ; yields {i32}:%1 +%result = add i32 %1, %1+
This last way of multiplying %X by 8 illustrates several important lexical features of LLVM:
@@ -365,24 +397,27 @@ 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: +; Declare the string constant as a global constant... -%.LC0 = internal constant [13 x i8 ] c"hello world\0A\00" ; [13 x i8 ]* +@.LC0 = internal constant [13 x i8] c"hello world\0A\00" ; [13 x i8]* ; External declaration of the puts function -declare i32 %puts(i8 *) ; i32(i8 *)* +declare i32 @puts(i8 *) ; i32(i8 *)* ; Definition of main function -define i32 %main() { ; i32()* +define i32 @main() { ; i32()* ; Convert [13x i8 ]* to i8 *... %cast210 = getelementptr [13 x i8 ]* %.LC0, i64 0, i64 0 ; i8 * + href="#i_getelementptr">getelementptr [13 x i8 ]* @.LC0, i64 0, i64 0 ; i8 * ; Call puts function to write out the string to stdout... call i32 %puts(i8 * %cast210) ; i32 + href="#i_call">call i32 @puts(i8 * %cast210) ; i32 ret i32 0+ href="#i_ret">ret i32 0
}
This example is made up of a global variable named ".LC0", an external declaration of the "puts" @@ -453,7 +488,6 @@ All Global Variables and Functions have one of the following types of linkage: until linked, if not linked, the symbol becomes null instead of being an undefined reference. -
The next two types of linkage are targeted for Microsoft Windows platform @@ -497,7 +532,8 @@ outside of the current module.
It is illegal for a function declaration to have any linkage type other than "externally visible", dllimport, or extern_weak.
- +Aliases can have only external, internal and weak +linkages.
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 never be modified (enabling better +an explicit section to be placed in, and may have an optional explicit alignment +specified. A variable may be defined as "thread_local", which means that it +will not be shared by threads (each thread will have a separated copy of the +variable). A variable may be defined as a global "constant," which indicates +that the contents of the variable will never 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.
@@ -636,9 +680,11 @@ a power of 2.For example, the following defines a global with an initializer, section, and alignment:
+- %G = constant float 1.0, section "foo", align 4 +@G = constant float 1.0, section "foo", align 4+
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 @@ -673,17 +720,12 @@ basic block a symbol table entry), contains a list of instructions, and ends with a terminator instruction (such as a branch or function return).
-The first basic block in a program is special in two ways: it is immediately +
The first basic block in a function is special in two ways: it is immediately executed on entrance to the function, and it is not allowed to have predecessor basic blocks (i.e. there can not be any branches to the entry block of a function). Because the block can have no predecessors, it also cannot have any PHI nodes.
-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.
-LLVM allows an explicit section to be specified for functions. If the target supports it, it will emit functions to the section specified.
@@ -695,32 +737,59 @@ a power of 2. + + +Aliases act as "second name" for the aliasee value (which can be either + function or global variable or bitcast of global value). Aliases may have an + optional linkage type, and an + optional visibility style.
+ ++@<Name> = [Linkage] [Visibility] alias <AliaseeTy> @<Aliasee> ++
The return type and each parameter of a function type may have a set of parameter attributes associated with them. Parameter attributes are used to communicate additional information about the result or parameters of - a function. Parameter attributes are considered to be part of the function - type so two functions types that differ only by the parameter attributes - are different function types.
+ a function. Parameter attributes are considered to be part of the function, + not of the function type, so functions with different parameter attributes + can have the same function type.Parameter attributes are simple keywords that follow the type specified. If multiple parameter attributes are needed, they are space separated. For - example:
- %someFunc = i16 (i8 sext %someParam) zext - %someFunc = i16 (i8 zext %someParam) zext-
Note that the two function types above are unique because the parameter has - a different attribute (sext in the first one, zext in the second). Also note - that the attribute for the function result (zext) comes immediately after the - argument list.
+ example: + ++declare i32 @printf(i8* noalias , ...) nounwind +declare i32 @atoi(i8*) nounwind readonly ++
Note that any attributes for the function result (nounwind, + readonly) come immediately after the argument list.
Currently, only the following parameter attributes are defined:
Each function may specify a garbage collector name, which is simply a +string.
+ +define void @f() gc "name" { ...The compiler declares the supported values of name. Specifying a +collector which will cause the compiler to alter its output in order to support +the named garbage collection algorithm.
+- module asm "inline asm code goes here" - module asm "more can go here" -
+module asm "inline asm code goes here" +module asm "more can go here" ++
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 @@ -778,13 +881,12 @@ desired. The syntax is very simple:
A module may specify a target specific data layout string that specifies how
-data is to be laid out in memory. The syntax for the data layout is simply:
-
target datalayout = "layout specification" --The layout specification consists of a list of specifications separated -by the minus sign character ('-'). Each specification starts with a letter -and may include other information after the letter to define some aspect of the -data layout. The specifications accepted are as follows: +data is to be laid out in memory. The syntax for the data layout is simply: +
target datalayout = "layout specification"+
The layout specification consists of a list of specifications +separated by the minus sign character ('-'). Each specification starts with a +letter and may include other information after the letter to define some +aspect of the data layout. The specifications accepted are as follows:
| Type | Description |
|---|---|
| i1 | True or False value |
| i16 | 16-bit value |
| i64 | 64-bit value |
| float | 32-bit floating point value |
| double | 64-bit floating point value |
The integer type is a very simple derived type that simply specifies an +arbitrary bit width for the integer type desired. Any bit width from 1 bit to +2^23-1 (about 8 million) can be specified.
+ ++ iN ++ +
The number of bits the integer will occupy is specified by the N +value.
+ +|
+ i1 + i4 + i8 + i16 + i32 + i42 + i64 + i1942652 + |
+
+ A boolean integer of 1 bit + A nibble sized integer of 4 bits. + A byte sized integer of 8 bits. + A half word sized integer of 16 bits. + A word sized integer of 32 bits. + An integer whose bit width is the answer. + A double word sized integer of 64 bits. + A really big integer of over 1 million bits. + |
+
|
- { i32, i32, i32 } - { float, i32 (i32) * } - |
-
- a triple of three i32 values - A pair, where the first element is a float and the second element - is a pointer to a function - that takes an i32, returning an i32. - |
+ { i32, i32, i32 } | +A triple of three i32 values | +
| { float, i32 (i32) * } | +A pair, where the first element is a float and the + second element is a pointer to a + function that takes an i32, returning + an i32. |
|
- < { i32, i32, i32 } > - < { float, i32 (i32) * } > - |
-
- a triple of three i32 values - A pair, where the first element is a float and the second element - is a pointer to a function - that takes an i32, returning an i32. - |
+ < { i32, i32, i32 } > | +A triple of three i32 values | +
| < { float, i32 (i32) * } > | +A pair, where the first element is a float and the + second element is a pointer to a + function that takes an i32, returning + an i32. |
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. +corresponds (for example) to the C notion of a forward declared structure type. In LLVM, opaque types can eventually be resolved to any type (not just a structure type).
@@ -1281,7 +1420,7 @@ and smaller aggregate constants.- %X = global i32 17 - %Y = global i32 42 - %Z = global [2 x i32*] [ i32* %X, i32* %Y ] +@X = global i32 17 +@Y = global i32 42 +@Z = global [2 x i32*] [ i32* @X, i32* @Y ]+
- i32 (i32) asm "bswap $0", "=r,r" +i32 (i32) asm "bswap $0", "=r,r"+
Inline assembler expressions may only be used as the callee operand of a call instruction. Thus, typically we have:
+Inline asms with side effects not visible in the constraint list must be marked @@ -1508,9 +1661,11 @@ as having side effects. This is done through the use of the 'sideeffect' keyword, like so:
+- call void asm sideeffect "eieio", ""() +call void asm sideeffect "eieio", ""()+
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 @@ -1744,10 +1899,10 @@ exception. Additionally, this is important for implementation of
- %retval = invoke i32 %Test(i32 15) to label %Continue
- unwind label %TestCleanup ; {i32}:retval set
- %retval = invoke coldcc i32 %Test(i32 15) to label %Continue
- unwind label %TestCleanup ; {i32}:retval set
+ %retval = invoke i32 %Test(i32 15) to label %Continue
+ unwind label %TestCleanup ; {i32}:retval set
+ %retval = invoke coldcc i32 %Test(i32 15) to label %Continue
+ unwind label %TestCleanup ; {i32}:retval set
@@ -1861,7 +2016,8 @@ Both arguments must have identical types.
The value produced is the integer or floating point difference of the two operands.
<result> = sub i32 4, %var ; yields {i32}:result = 4 - %var
+
+ <result> = sub i32 4, %var ; yields {i32}:result = 4 - %var
<result> = sub i32 0, %val ; yields {i32}:result = -%var
@@ -1948,10 +2104,10 @@ Instruction
The 'fdiv' instruction returns the quotient of its two
operands.
Arguments:
-The two arguments to the 'div' instruction must be
+
The two arguments to the 'fdiv' instruction must be
floating point values. Both arguments must have
identical types. This instruction can also take vector
-versions of the values in which case the elements must be floating point.
+versions of floating point values.
Semantics:
The value produced is the floating point quotient of the two operands.
Example:
@@ -1971,7 +2127,8 @@ unsigned division of its two arguments.
Arguments:
The two arguments to the 'urem' instruction must be
integer values. Both arguments must have identical
-types.
+types. This instruction can also take vector versions
+of the values in which case the elements must be integers.
Semantics:
This instruction returns the unsigned integer remainder of a division.
This instruction always performs an unsigned division to get the remainder,
@@ -1990,7 +2147,10 @@ Instruction
The 'srem' instruction returns the remainder from the -signed division of its two operands.
+signed division of its two operands. This instruction can also take +vector versions of the values in which case +the elements must be integers. +The two arguments to the 'srem' instruction must be integer values. Both arguments must have identical @@ -2022,7 +2182,8 @@ division of its two operands.
The two arguments to the 'frem' instruction must be floating point values. Both arguments must have -identical types.
+identical types. This instruction can also take vector +versions of floating point values.This instruction returns the remainder of a division.
<result> = shl <ty> <var1>, <var2> ; yields {ty}:result
+
The 'shl' instruction returns the first operand shifted to the left a specified number of bits.
+Both arguments to the 'shl' instruction must be the same integer type.
+The value produced is var1 * 2var2.
+ +The value produced is var1 * 2var2. If +var2 is (statically or dynamically) equal to or larger than the number +of bits in var1, the result is undefined.
+
<result> = shl i32 4, %var ; yields {i32}: 4 << %var
<result> = shl i32 4, 2 ; yields {i32}: 16
<result> = shl i32 1, 10 ; yields {i32}: 1024
+ <result> = shl i32 1, 32 ; undefined
@@ -2073,16 +2244,18 @@ Instruction
The 'lshr' instruction (logical shift right) returns the first -operand shifted to the right a specified number of bits.
+operand shifted to the right a specified number of bits with zero fill.Both arguments to the 'lshr' instruction must be the same integer type.
This instruction always performs a logical shift right operation. The most significant bits of the result will be filled with zero bits after the -shift.
+shift. If var2 is (statically or dynamically) equal to or larger than +the number of bits in var1, the result is undefined.
@@ -2090,6 +2263,7 @@ shift.
<result> = lshr i32 4, 2 ; yields {i32}:result = 1
<result> = lshr i8 4, 3 ; yields {i8}:result = 0
<result> = lshr i8 -2, 1 ; yields {i8}:result = 0x7FFFFFFF
+ <result> = lshr i32 1, 32 ; undefined
@@ -2104,7 +2278,7 @@ Instruction
The 'ashr' instruction (arithmetic shift right) returns the first -operand shifted to the right a specified number of bits.
+operand shifted to the right a specified number of bits with sign extension.Both arguments to the 'ashr' instruction must be the same @@ -2113,7 +2287,9 @@ operand shifted to the right a specified number of bits.
This instruction always performs an arithmetic shift right operation, The most significant bits of the result will be filled with the sign bit -of var1.
+of var1. If var2 is (statically or dynamically) equal to or +larger than the number of bits in var1, the result is undefined. +
@@ -2121,6 +2297,7 @@ of var1.
<result> = ashr i32 4, 2 ; yields {i32}:result = 1
<result> = ashr i8 4, 3 ; yields {i8}:result = 0
<result> = ashr i8 -2, 1 ; yields {i8}:result = -1
+ <result> = ashr i32 1, 32 ; undefined
@@ -2297,7 +2474,7 @@ identical types.
LLVM supports several instructions to represent vector operations in a -target-independent manner. This instructions cover the element-access and +target-independent manner. These instructions cover the element-access and vector-specific operations needed to process vectors effectively. While LLVM does directly support these vector operations, many sophisticated algorithms will want to use target-specific intrinsics to take full advantage of a specific @@ -2445,7 +2622,7 @@ operand may be undef if performing a shuffle from only one vector.
%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
- <4 x i32> <i32 0, i32 4, i32 1, i32 5> ; yields <4 x i32>
+ <4 x i32> <i32 0, i32 4, i32 1, i32 5> ; yields <4 x i32>
%result = shufflevector <4 x i32> %v1, <4 x i32> undef,
<4 x i32> <i32 0, i32 1, i32 2, i32 3> ; yields <4 x i32> - Identity shuffle.
@@ -2507,11 +2684,11 @@ a pointer is returned.
%array = malloc [4 x i8 ] ; yields {[%4 x i8]*}:array
- %size = add i32 2, 2 ; yields {i32}:size = i32 4
- %array1 = malloc i8, i32 4 ; yields {i8*}:array1
- %array2 = malloc [12 x i8], i32 %size ; yields {[12 x i8]*}:array2
- %array3 = malloc i32, i32 4, align 1024 ; yields {i32*}:array3
- %array4 = malloc i32, align 1024 ; yields {i32*}:array4
+ %size = add i32 2, 2 ; yields {i32}:size = i32 4
+ %array1 = malloc i8, i32 4 ; yields {i8*}:array1
+ %array2 = malloc [12 x i8], i32 %size ; yields {[12 x i8]*}:array2
+ %array3 = malloc i32, i32 4, align 1024 ; yields {i32*}:array3
+ %array4 = malloc i32, align 1024 ; yields {i32*}:array4
The 'alloca' instruction allocates memory on the current -stack frame of the procedure that is live until the current function +
The 'alloca' instruction allocates memory on the stack frame of the +currently executing function, to be automatically released when this function returns to its caller.
%ptr = alloca i32 ; yields {i32*}:ptr
- %ptr = alloca i32, i32 4 ; yields {i32*}:ptr
- %ptr = alloca i32, i32 4, align 1024 ; yields {i32*}:ptr
+ %ptr = alloca i32, i32 4 ; yields {i32*}:ptr
+ %ptr = alloca i32, i32 4, align 1024 ; yields {i32*}:ptr
%ptr = alloca i32, align 1024 ; yields {i32*}:ptr
@@ -2607,7 +2784,7 @@ instructions), the memory is reclaimed.
Instruction
<result> = load <ty>* <pointer>+
<result> = volatile load <ty>* <pointer>
<result> = load <ty>* <pointer>[, align <alignment>]
<result> = volatile load <ty>* <pointer>[, align <alignment>]
The 'load' instruction is used to read from memory.
store <ty> <value>, <ty>* <pointer> ; yields {void}
- volatile store <ty> <value>, <ty>* <pointer> ; yields {void}
+ store <ty> <value>, <ty>* <pointer>[, align <alignment>] ; yields {void}
+ volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] ; yields {void}
Overview:
The 'store' instruction is used to write to memory.
Arguments:
There are two arguments to the 'store' instruction: a value
-to store and an address in which to store it. The type of the '<pointer>'
+to store and an address at which to store it. The type of the '<pointer>'
operand must be a pointer to the type of the '<value>'
operand. If the store is marked as volatile, then the
optimizer is not allowed to modify the number or order of execution of
@@ -2650,9 +2827,8 @@ this store with other volatile load and <pointer>' operand.
Example:
%ptr = alloca i32 ; yields {i32*}:ptr
- store i32 3, i32* %ptr ; yields {void}
- %val = load i32* %ptr ; yields {i32}:val = i32 3
+ store i32 3, i32* %ptr ; yields {void}
+ %val = load i32* %ptr ; yields {i32}:val = i32 3
For example, let's consider a C code fragment and how it gets compiled to LLVM:
+
- struct RT {
- char A;
- i32 B[10][20];
- char C;
- };
- struct ST {
- i32 X;
- double Y;
- struct RT Z;
- };
-
- define i32 *foo(struct ST *s) {
- return &s[1].Z.B[5][13];
- }
+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];
+}
+The LLVM code generated by the GCC frontend is:
+
- %RT = type { i8 , [10 x [20 x i32]], i8 }
- %ST = type { i32, double, %RT }
+%RT = type { i8 , [10 x [20 x i32]], i8 }
+%ST = type { i32, double, %RT }
- define i32* %foo(%ST* %s) {
- entry:
- %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
- ret i32* %reg
- }
+define i32* %foo(%ST* %s) {
+entry:
+ %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
+ ret i32* %reg
+}
+In the example above, the first index is indexing into the '%ST*' @@ -2743,8 +2923,8 @@ the LLVM code for the given testcase is equivalent to:
define i32* %foo(%ST* %s) {
%t1 = getelementptr %ST* %s, i32 1 ; yields %ST*:%t1
- %t2 = getelementptr %ST* %t1, i32 0, i32 2 ; yields %RT*:%t2
- %t3 = getelementptr %RT* %t2, i32 0, i32 1 ; yields [10 x [20 x i32]]*:%t3
+ %t2 = getelementptr %ST* %t1, i32 0, i32 2 ; yields %RT*:%t2
+ %t3 = getelementptr %RT* %t2, i32 0, i32 1 ; yields [10 x [20 x i32]]*:%t3
%t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 ; yields [20 x i32]*:%t4
%t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 ; yields i32*:%t5
ret i32* %t5
@@ -2842,10 +3022,7 @@ also be of integer type. The bit size of the
Semantics:
The zext fills the high order bits of the value with zero
-bits until it reaches the size of the destination type, ty2. When the
-the operand and the type are the same size, no bit filling is done and the
-cast is considered a no-op cast because no bits change (only the type
-changes).
+bits until it reaches the size of the destination type, ty2.
When zero extending from i1, the result will always be either 0 or 1.
@@ -2882,9 +3059,7 @@ also be of integer type. The bit size of the
The 'sext' instruction performs a sign extension by copying the sign
bit (highest order bit) of the value until it reaches the bit size of
-the type ty2. When the the operand and the type are the same size,
-no bit filling is done and the cast is considered a no-op cast because
-no bits change (only the type changes).
+the type ty2.
When sign extending from i1, the extension always results in -1 or 0.
@@ -2976,34 +3151,32 @@ used to make a no-op cast because it always changes bits. Use
Syntax:
- <result> = fp2uint <ty> <value> to <ty2> ; yields ty2
+ <result> = fptoui <ty> <value> to <ty2> ; yields ty2
Overview:
-The 'fp2uint' converts a floating point value to its
+
The 'fptoui' converts a floating point value to its
unsigned integer equivalent of type ty2.
Arguments:
-The 'fp2uint' instruction takes a value to cast, which must be a
-floating point value, and a type to cast it to, which
-must be an integer type.
+The 'fptoui' instruction takes a value to cast, which must be a
+scalar or vector floating point value, and a type
+to cast it to ty2, which must be an integer
+type. If ty is a vector floating point type, ty2 must be a
+vector integer type with the same number of elements as ty
Semantics:
- The 'fp2uint' instruction converts its
+
The 'fptoui' instruction converts its
floating point operand into the nearest (rounding
towards zero) unsigned integer value. If the value cannot fit in ty2,
the results are undefined.
-When converting to i1, the conversion is done as a comparison against
-zero. If the value was zero, the i1 result will be false.
-If the value was non-zero, the i1 result will be true.
-
Example:
- %X = fp2uint double 123.0 to i32 ; yields i32:123
- %Y = fp2uint float 1.0E+300 to i1 ; yields i1:true
- %X = fp2uint float 1.04E+17 to i8 ; yields undefined:1
+ %X = fptoui double 123.0 to i32 ; yields i32:123
+ %Y = fptoui float 1.0E+300 to i1 ; yields undefined:1
+ %X = fptoui float 1.04E+17 to i8 ; yields undefined:1
@@ -3023,11 +3196,12 @@ If the value was non-zero, the i1 result will be true.
floating point value to type ty2.
-
Arguments:
The 'fptosi' instruction takes a value to cast, which must be a
-floating point value, and a type to cast it to, which
-must also be an integer type.
+scalar or vector floating point value, and a type
+to cast it to ty2, which must be an integer
+type. If ty is a vector floating point type, ty2 must be a
+vector integer type with the same number of elements as ty
Semantics:
The 'fptosi' instruction converts its
@@ -3035,14 +3209,10 @@ must also be an integer type.
towards zero) signed integer value. If the value cannot fit in ty2,
the results are undefined.
-When converting to i1, the conversion is done as a comparison against
-zero. If the value was zero, the i1 result will be false.
-If the value was non-zero, the i1 result will be true.
-
Example:
%X = fptosi double -123.0 to i32 ; yields i32:-123
- %Y = fptosi float 1.0E-247 to i1 ; yields i1:true
+ %Y = fptosi float 1.0E-247 to i1 ; yields undefined:1
%X = fptosi float 1.04E+17 to i8 ; yields undefined:1
@@ -3062,22 +3232,22 @@ If the value was non-zero, the i1 result will be true.
The 'uitofp' instruction regards value as an unsigned
integer and converts that value to the ty2 type.
-
Arguments:
-The 'uitofp' instruction takes a value to cast, which must be an
-integer value, and a type to cast it to, which must
-be a floating point type.
+The 'uitofp' instruction takes a value to cast, which must be a
+scalar or vector integer value, and a type to cast it
+to ty2, which must be an floating point
+type. If ty is a vector integer type, ty2 must be a vector
+floating point type with the same number of elements as ty
Semantics:
The 'uitofp' instruction interprets its operand as an unsigned
integer quantity and converts it to the corresponding floating point value. If
the value cannot fit in the floating point value, the results are undefined.
-
Example:
%X = uitofp i32 257 to float ; yields float:257.0
- %Y = uitofp i8 -1 to double ; yields double:255.0
+ %Y = uitofp i8 -1 to double ; yields double:255.0
@@ -3097,9 +3267,11 @@ the value cannot fit in the floating point value, the results are undefined.
integer and converts that value to the ty2 type.
Arguments:
-The 'sitofp' instruction takes a value to cast, which must be an
-integer value, and a type to cast it to, which must be
-a floating point type.
+The 'sitofp' instruction takes a value to cast, which must be a
+scalar or vector integer value, and a type to cast it
+to ty2, which must be an floating point
+type. If ty is a vector integer type, ty2 must be a vector
+floating point type with the same number of elements as ty
Semantics:
The 'sitofp' instruction interprets its operand as a signed
@@ -3109,7 +3281,7 @@ the value cannot fit in the floating point value, the results are undefined.
Example:
%X = sitofp i32 257 to float ; yields float:257.0
- %Y = sitofp i8 -1 to double ; yields double:-1.0
+ %Y = sitofp i8 -1 to double ; yields double:-1.0
@@ -3139,12 +3311,13 @@ must be a pointer value, and a type to cast it to
truncating or zero extending that value to the size of the integer type. If
value is smaller than ty2 then a zero extension is done. If
value is larger than ty2 then a truncation is done. If they
-are the same size, then nothing is done (no-op cast).
+are the same size, then nothing is done (no-op cast) other than a type
+change.
Example:
- %X = ptrtoint i32* %X to i8 ; yields truncation on 32-bit
- %Y = ptrtoint i32* %x to i64 ; yields zero extend on 32-bit
+ %X = ptrtoint i32* %X to i8 ; yields truncation on 32-bit architecture
+ %Y = ptrtoint i32* %x to i64 ; yields zero extension on 32-bit architecture
@@ -3178,9 +3351,9 @@ nothing is done (no-op cast).
Example:
- %X = inttoptr i32 255 to i32* ; yields zero extend on 64-bit
- %X = inttoptr i32 255 to i32* ; yields no-op on 32-bit
- %Y = inttoptr i16 0 to i32* ; yields zero extend on 32-bit
+ %X = inttoptr i32 255 to i32* ; yields zero extension on 64-bit architecture
+ %X = inttoptr i32 255 to i32* ; yields no-op on 32-bit architecture
+ %Y = inttoptr i64 0 to i32* ; yields truncation on 32-bit architecture
@@ -3217,7 +3390,7 @@ other types, use the inttoptr or
Example:
- %X = bitcast i8 255 to i8 ; yields i8 :-1
+ %X = bitcast i8 255 to i8 ; yields i8 :-1
%Y = bitcast i32* %x to sint* ; yields sint*:%x
%Z = bitcast <2xint> %V to i64; ; yields i64: %V
@@ -3235,16 +3408,15 @@ instructions, which defy better classification.
Syntax:
- <result> = icmp <cond> <ty> <var1>, <var2>
-; yields {i1}:result
+ <result> = icmp <cond> <ty> <var1>, <var2> ; yields {i1}:result
Overview:
The 'icmp' instruction returns a boolean value based on comparison
of its two integer operands.
Arguments:
The 'icmp' instruction takes three operands. The first operand is
-the condition code which indicates the kind of comparison to perform. It is not
-a value, just a keyword. The possibilities for the condition code are:
+the condition code indicating the kind of comparison to perform. It is not
+a value, just a keyword. The possible condition code are:
- eq: equal
- ne: not equal
@@ -3287,7 +3459,7 @@ yields a i1 result, as follows:
true if var1 is less than or equal to var2.
If the operands are pointer typed, the pointer
-values are treated as integers and then compared.
+values are compared as if they were integers.
Example:
<result> = icmp eq i32 4, 5 ; yields: result=false
@@ -3304,16 +3476,15 @@ values are treated as integers and then compared.
Syntax:
- <result> = fcmp <cond> <ty> <var1>, <var2>
-; yields {i1}:result
+ <result> = fcmp <cond> <ty> <var1>, <var2> ; yields {i1}:result
Overview:
The 'fcmp' instruction returns a boolean value based on comparison
of its floating point operands.
Arguments:
The 'fcmp' instruction takes three operands. The first operand is
-the condition code which indicates the kind of comparison to perform. It is not
-a value, just a keyword. The possibilities for the condition code are:
+the condition code indicating the kind of comparison to perform. It is not
+a value, just a keyword. The possible condition code are:
- false: no comparison, always returns false
- oeq: ordered and equal
@@ -3332,13 +3503,11 @@ a value, just a keyword. The possibilities for the condition code are:
- uno: unordered (either nans)
- true: no comparison, always returns true
-In the preceding, ordered means that neither operand is a QNAN while
+
Ordered means that neither operand is a QNAN while
unordered means that either operand may be a QNAN.
The val1 and val2 arguments must be
floating point typed. They must have identical
types.
-In the foregoing, ordered means that neither operand is a QNAN and
-unordered means that either operand is a QNAN.
Semantics:
The 'fcmp' compares var1 and var2 according to
the condition code given as cond. The comparison performed always
@@ -3392,7 +3561,7 @@ Instruction
The 'phi' instruction is used to implement the φ node in
the SSA graph representing the function.
Arguments:
-The type of the incoming values are specified with the first type
+
The type of the incoming values is specified with the first type
field. After this, the 'phi' instruction takes a list of pairs
as arguments, with one pair for each predecessor basic block of the
current block. Only values of first class
@@ -3402,9 +3571,9 @@ may be used as the label arguments.
block and the PHI instructions: i.e. PHI instructions must be first in
a basic block.
Semantics:
-At runtime, the 'phi' instruction logically takes on the
-value specified by the parameter, depending on which basic block we
-came from in the last terminator instruction.
+At runtime, the 'phi' instruction logically takes on the value
+specified by the pair corresponding to the predecessor basic block that executed
+just prior to the current block.
Example:
Loop: ; Infinite loop that counts from 0 on up...
%indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
%nextindvar = add i32 %indvar, 1
br label %Loop
@@ -3460,7 +3629,7 @@ value argument; otherwise, it returns the second value argument.
Syntax:
- <result> = [tail] call [cconv] <ty>* <fnptrval>(<param list>)
+ <result> = [tail] call [cconv] <ty> [<fnty>*] <fnptrval>(<param list>)
Overview:
@@ -3485,10 +3654,15 @@ value argument; otherwise, it returns the second value argument.
to using C calling conventions.
'ty': 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.
+'ty': the type of the call instruction itself which is also + the type of the return value. Functions that return no value are marked + void.
+'fnty': 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.
'fnptrval': An LLVM value containing a pointer to a function to @@ -3518,10 +3692,11 @@ the invoke instruction.
- %retval = call i32 %test(i32 %argc) - call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42); - %X = tail call i32 %foo() - %Y = tail call fastcc i32 %foo() + %retval = call i32 @test(i32 %argc) + call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42); + %X = tail call i32 @foo() + %Y = tail call fastcc i32 @foo() + %Z = call void %foo(i8 97 signext)@@ -3549,7 +3724,7 @@ the "variable argument" area of a function call. It is used to implement the
This instruction takes a va_list* value and the type of the argument. It returns a value of the specified argument type and -increments the va_list to point to the next argument. Again, the +increments the va_list to point to the next argument. The actual type of va_list is target specific.
LLVM supports the notion of an "intrinsic function". These functions have well known names and semantics and are required to follow certain restrictions. Overall, these intrinsics represent an extension mechanism for the LLVM -language that does not require changing all of the transformations in LLVM to -add to the language (or the bytecode reader/writer, the parser, -etc...).
+language that does not require changing all of the transformations in LLVM when +adding to the language (or the bitcode reader/writer, the parser, etc...).Intrinsic function names must all start with an "llvm." 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.
- -Some intrinsic functions can be overloaded. That is, the intrinsic represents -a family of functions that perform the same operation but on different data -types. This is most frequent with the integer types. Since LLVM can represent -over 8 million different integer types, there is a way to declare an intrinsic -that can be overloaded based on its arguments. Such intrinsics will have the -names of the arbitrary types encoded into the intrinsic function name, each -preceded by a period. For example, the llvm.ctpop function can take an -integer of any width. This leads to a family of functions such as -i32 @llvm.ctpop.i8(i8 %val) and i32 @llvm.ctpop.i29(i29 %val). -
- +prefix is reserved in LLVM for intrinsic names; thus, function names may not +begin with this prefix. Intrinsic functions must always be external functions: +you cannot define the body of intrinsic functions. Intrinsic functions may +only be used in call or invoke instructions: it is illegal to take the address +of an intrinsic function. Additionally, because intrinsic functions are part +of the LLVM language, it is required if any are added that they be documented +here. + +Some intrinsic functions can be overloaded, i.e., the intrinsic represents +a family of functions that perform the same operation but on different data +types. Because LLVM can represent over 8 million different integer types, +overloading is used commonly to allow an intrinsic function to operate on any +integer type. One or more of the argument types or the result type can be +overloaded to accept any integer type. Argument types may also be defined as +exactly matching a previous argument's type or the result type. This allows an +intrinsic function which accepts multiple arguments, but needs all of them to +be of the same type, to only be overloaded with respect to a single argument or +the result.
+ +Overloaded intrinsics will have the names of its overloaded argument types +encoded into its function name, each preceded by a period. Only those types +which are overloaded result in a name suffix. Arguments whose type is matched +against another type do not. For example, the llvm.ctpop function can +take an integer of any width and returns an integer of exactly the same integer +width. This leads to a family of functions such as +i8 @llvm.ctpop.i8(i8 %val) and i29 @llvm.ctpop.i29(i29 %val). +Only one type, the return type, is overloaded, and only one type suffix is +required. Because the argument's type is matched against the return type, it +does not require its own name suffix.
To learn how to add an intrinsic function, please see the Extending LLVM Guide. @@ -3628,27 +3813,28 @@ named macros defined in the <stdarg.h> header file.
All of these functions operate on arguments that use a target-specific value type "va_list". 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.
+transformations should be prepared to handle these functions regardless of +the type used.This example shows how the va_arg instruction and the variable argument handling intrinsic functions are used.
+
define i32 @test(i32 %X, ...) {
; Initialize variable argument processing
- %ap = alloca i8 *
+ %ap = alloca i8*
%ap2 = bitcast i8** %ap to i8*
call void @llvm.va_start(i8* %ap2)
; Read a single integer argument
- %tmp = va_arg i8 ** %ap, i32
+ %tmp = va_arg i8** %ap, i32
; Demonstrate usage of llvm.va_copy and llvm.va_end
- %aq = alloca i8 *
+ %aq = alloca i8*
%aq2 = bitcast i8** %aq to i8*
- call void @llvm.va_copy(i8 *%aq2, i8* %ap2)
+ call void @llvm.va_copy(i8* %aq2, i8* %ap2)
call void @llvm.va_end(i8* %aq2)
; Stop processing of arguments.
@@ -3662,6 +3848,8 @@ declare void @llvm.va_end(i8*)
The 'llvm.va_start' intrinsic works just like the va_start macro available in C. In a target-dependent way, it initializes the -va_list element the argument points to, so that the next call to +va_list element to which the argument points, so that the next call to va_arg will produce the first variable argument passed to the function. Unlike the C va_start macro, this intrinsic does not need to know the -last argument of the function, the compiler can figure that out.
+last argument of the function as the compiler can figure that out.declare void @llvm.va_end(i8* <arglist>)
The 'llvm.va_end' intrinsic destroys <arglist> +
The 'llvm.va_end' intrinsic destroys *<arglist>, which has been initialized previously with llvm.va_start or llvm.va_copy.
The argument is a va_list to destroy.
+The argument is a pointer to a va_list to destroy.
The 'llvm.va_end' intrinsic works just like the va_end -macro available in C. In a target-dependent way, it destroys the va_list. -Calls to llvm.va_start and llvm.va_copy must be matched exactly -with calls to llvm.va_end.
+macro available in C. In a target-dependent way, it destroys the +va_list element to which the argument points. Calls to llvm.va_start and +llvm.va_copy must be matched exactly with calls to +llvm.va_end. @@ -3734,8 +3923,8 @@ with calls to llvm.va_end.The 'llvm.va_copy' intrinsic copies the current argument position from -the source argument list to the destination argument list.
+The 'llvm.va_copy' intrinsic copies the current argument position +from the source argument list to the destination argument list.
The 'llvm.va_copy' intrinsic works just like the va_copy macro -available in C. In a target-dependent way, it copies the source -va_list element into the destination list. This intrinsic is necessary -because the llvm.va_start intrinsic may be -arbitrarily complex and require memory allocation, for example.
+The 'llvm.va_copy' intrinsic works just like the va_copy +macro available in C. In a target-dependent way, it copies the source +va_list element into the destination va_list element. This +intrinsic is necessary because the +llvm.va_start intrinsic may be arbitrarily complex and require, for +example, memory allocation.
@@ -3782,7 +3972,7 @@ href="GarbageCollection.html">Accurate Garbage Collection with LLVM.- declare void @llvm.gcroot(<ty>** %ptrloc, <ty2>* %metadata) + declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
- declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr) + declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
- declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2) + declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
- declare i8 *@llvm.frameaddress(i32 <level>) + declare i8 *@llvm.frameaddress(i32 <level>)
- declare i8 *@llvm.stacksave() + declare i8 *@llvm.stacksave()
- declare void @llvm.prefetch(i8 * <address>, - i32 <rw>, i32 <locality>) + declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
- declare void @llvm.pcmarker( i32 <id> ) + declare void @llvm.pcmarker(i32 <id>)
This is an overloaded intrinsic. You can use llvm.sqrt on any +floating point or vector of floating point type. Not all targets support all +types however.
- declare float @llvm.sqrt.f32(float %Val) - declare double @llvm.sqrt.f64(double %Val) + declare float @llvm.sqrt.f32(float %Val) + declare double @llvm.sqrt.f64(double %Val) + declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val) + declare fp128 @llvm.sqrt.f128(fp128 %Val) + declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
The 'llvm.sqrt' intrinsics return the sqrt of the specified operand, -returning the same value as the libm 'sqrt' function would. Unlike +returning the same value as the libm 'sqrt' functions would. Unlike sqrt in libm, however, llvm.sqrt has undefined behavior for negative numbers (which allows for better optimization).
@@ -4371,7 +4566,7 @@ The argument and return value are floating point numbers of the same type.-This function returns the sqrt of the specified operand if it is a positive +This function returns the sqrt of the specified operand if it is a nonnegative floating point number.
This is an overloaded intrinsic. You can use llvm.powi on any +floating point or vector of floating point type. Not all targets support all +types however.
- declare float @llvm.powi.f32(float %Val, i32 %power) - declare double @llvm.powi.f64(double %Val, i32 %power) + declare float @llvm.powi.f32(float %Val, i32 %power) + declare double @llvm.powi.f64(double %Val, i32 %power) + declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power) + declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power) + declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
The 'llvm.powi.*' intrinsics return the first operand raised to the specified (positive or negative) power. The order of evaluation of -multiplications is not defined. +multiplications is not defined. When a vector of floating point type is +used, the second argument remains a scalar integer value.
This is an overloaded intrinsic. You can use llvm.sin on any +floating point or vector of floating point type. Not all targets support all +types however. +
+ declare float @llvm.sin.f32(float %Val) + declare double @llvm.sin.f64(double %Val) + declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val) + declare fp128 @llvm.sin.f128(fp128 %Val) + declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val) ++ +
+The 'llvm.sin.*' intrinsics return the sine of the operand. +
+ ++The argument and return value are floating point numbers of the same type. +
+ ++This function returns the sine of the specified operand, returning the +same values as the libm sin functions would, and handles error +conditions in the same way.
+This is an overloaded intrinsic. You can use llvm.cos on any +floating point or vector of floating point type. Not all targets support all +types however. +
+ declare float @llvm.cos.f32(float %Val) + declare double @llvm.cos.f64(double %Val) + declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val) + declare fp128 @llvm.cos.f128(fp128 %Val) + declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val) ++ +
+The 'llvm.cos.*' intrinsics return the cosine of the operand. +
+ ++The argument and return value are floating point numbers of the same type. +
+ ++This function returns the cosine of the specified operand, returning the +same values as the libm cos functions would, and handles error +conditions in the same way.
+This is an overloaded intrinsic. You can use llvm.pow on any +floating point or vector of floating point type. Not all targets support all +types however. +
+ declare float @llvm.pow.f32(float %Val, float %Power) + declare double @llvm.pow.f64(double %Val, double %Power) + declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power) + declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power) + declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power) ++ +
+The 'llvm.pow.*' intrinsics return the first operand raised to the +specified (positive or negative) power. +
+ ++The second argument is a floating point power, and the first is a value to +raise to that power. +
+ ++This function returns the first value raised to the second power, +returning the +same values as the libm pow functions would, and handles error +conditions in the same way.
+This is an overloaded intrinsic function. You can use bswap on any integer -type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix -that includes the type for the result and the operand. +type that is an even number of bytes (i.e. BitWidth % 16 == 0).
- declare i16 @llvm.bswap.i16.i16(i16 <id>) - declare i32 @llvm.bswap.i32.i32(i32 <id>) - declare i64 @llvm.bswap.i64.i64(i64 <id>) + declare i16 @llvm.bswap.i16(i16 <id>) + declare i32 @llvm.bswap.i32(i32 <id>) + declare i64 @llvm.bswap.i64(i64 <id>)
-The llvm.bswap.16.i16 intrinsic returns an i16 value that has the high +The llvm.bswap.i16 intrinsic returns an i16 value that has the high and low byte of the input i16 swapped. Similarly, the llvm.bswap.i32 intrinsic returns an i32 value that has the four bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned -i32 will have its bytes in 3, 2, 1, 0 order. The llvm.bswap.i48.i48, -llvm.bswap.i64.i64 and other intrinsics extend this concept to +i32 will have its bytes in 3, 2, 1, 0 order. The llvm.bswap.i48, +llvm.bswap.i64 and other intrinsics extend this concept to additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
@@ -4476,11 +4797,11 @@ additional even-byte lengths (6 bytes, 8 bytes and more, respectively).This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit width. Not all targets support all bit widths however.
- declare i32 @llvm.ctpop.i8 (i8 <src>) - declare i32 @llvm.ctpop.i16(i16 <src>) + declare i8 @llvm.ctpop.i8 (i8 <src>) + declare i16 @llvm.ctpop.i16(i16 <src>) declare i32 @llvm.ctpop.i32(i32 <src>) - declare i32 @llvm.ctpop.i64(i64 <src>) - declare i32 @llvm.ctpop.i256(i256 <src>) + declare i64 @llvm.ctpop.i64(i64 <src>) + declare i256 @llvm.ctpop.i256(i256 <src>)
This is an overloaded intrinsic. You can use llvm.ctlz on any integer bit width. Not all targets support all bit widths however.
- declare i32 @llvm.ctlz.i8 (i8 <src>) - declare i32 @llvm.ctlz.i16(i16 <src>) + declare i8 @llvm.ctlz.i8 (i8 <src>) + declare i16 @llvm.ctlz.i16(i16 <src>) declare i32 @llvm.ctlz.i32(i32 <src>) - declare i32 @llvm.ctlz.i64(i64 <src>) - declare i32 @llvm.ctlz.i256(i256 <src>) + declare i64 @llvm.ctlz.i64(i64 <src>) + declare i256 @llvm.ctlz.i256(i256 <src>)
This is an overloaded intrinsic. You can use llvm.cttz on any integer bit width. Not all targets support all bit widths however.
- declare i32 @llvm.cttz.i8 (i8 <src>) - declare i32 @llvm.cttz.i16(i16 <src>) + declare i8 @llvm.cttz.i8 (i8 <src>) + declare i16 @llvm.cttz.i16(i16 <src>) declare i32 @llvm.cttz.i32(i32 <src>) - declare i32 @llvm.cttz.i64(i64 <src>) - declare i32 @llvm.cttz.i256(i256 <src>) + declare i64 @llvm.cttz.i64(i64 <src>) + declare i256 @llvm.cttz.i256(i256 <src>)
This is an overloaded intrinsic. You can use llvm.part.select on any integer bit width.
- declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit) - declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit) + declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit) + declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
In reverse mode, a similar computation is made except that:
-In reverse mode, a similar computation is made except that the bits are +returned in the reverse order. So, for example, if X has the value +i16 0x0ACF (101011001111) and we apply +part.select(i16 X, 8, 3) to it, we get back the value +i16 0x0026 (000000100110).
+This is an overloaded intrinsic. You can use llvm.part.set +on any integer bit width. +
+ declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi) + declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi) ++ +
The 'llvm.part.set' family of intrinsic functions replaces a range +of bits in an integer value with another integer value. It returns the integer +with the replaced bits.
+ +The first argument, %val and the result may be integer types of +any bit width but they must have the same bit width. %val is the value +whose bits will be replaced. The second argument, %repl may be an +integer of any bit width. The third and fourth arguments must be i32 +type since they specify only a bit index.
+ +The operation of the 'llvm.part.set' intrinsic has two modes +of operation: forwards and reverse. If %lo is greater than +%hi then the intrinsic operates in reverse mode. Otherwise it +operates in forward mode.
+For both modes, the %repl value is prepared for use by either +truncating it down to the size of the replacement area or zero extending it +up to that size.
+In forward mode, the bits between %lo and %hi (inclusive) +are replaced with corresponding bits from %repl. That is the 0th bit +in %repl replaces the %loth bit in %val and etc. up +to the %hith bit. +
In reverse mode, a similar computation is made except that the bits are +reversed. That is, the 0th bit in %repl replaces the +%hi bit in %val and etc. down to the %loth bit. +
+ llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F + llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F + llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F + llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7 + llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07 +
+ This intrinsic makes it possible to excise one parameter, marked with + the nest attribute, from a function. The result is a callable + function pointer lacking the nest parameter - the caller does not need + to provide a value for it. Instead, the value to use is stored in + advance in a "trampoline", a block of memory usually allocated + on the stack, which also contains code to splice the nest value into the + argument list. This is used to implement the GCC nested function address + extension. +
++ For example, if the function is + i32 f(i8* nest %c, i32 %x, i32 %y) then the resulting function + pointer has signature i32 (i32, i32)*. It can be created as follows:
++ %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86 + %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0 + %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval ) + %fp = bitcast i8* %p to i32 (i32, i32)* ++
The call %val = call i32 %fp( i32 %x, i32 %y ) is then equivalent + to %val = call i32 %f( i8* %nval, i32 %x, i32 %y ).
++declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>) ++
+ This fills the memory pointed to by tramp with code + and returns a function pointer suitable for executing it. +
++ The llvm.init.trampoline intrinsic takes three arguments, all + pointers. The tramp argument must point to a sufficiently large + and sufficiently aligned block of memory; this memory is written to by the + intrinsic. Note that the size and the alignment are target-specific - LLVM + currently provides no portable way of determining them, so a front-end that + generates this intrinsic needs to have some target-specific knowledge. + The func argument must hold a function bitcast to an i8*. +
++ The block of memory pointed to by tramp is filled with target + dependent code, turning it into a function. A pointer to this function is + returned, but needs to be bitcast to an + appropriate function pointer type + before being called. The new function's signature is the same as that of + func with any arguments marked with the nest attribute + removed. At most one such nest argument is allowed, and it must be + of pointer type. Calling the new function is equivalent to calling + func with the same argument list, but with nval used for the + missing nest argument. If, after calling + llvm.init.trampoline, the memory pointed to by tramp is + modified, then the effect of any later call to the returned function pointer is + undefined. +
+This class of intrinsics is designed to be generic and has +no specific purpose.
++ declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> ) ++ +
+The 'llvm.var.annotation' intrinsic +
+ ++The first argument is a pointer to a value, the second is a pointer to a +global string, the third is a pointer to a global string which is the source +file name, and the last argument is the line number. +
+ ++This intrinsic allows annotation of local variables with arbitrary strings. +This can be useful for special purpose optimizations that want to look for these + annotations. These have no other defined use, they are ignored by code + generation and optimization. +
This is an overloaded intrinsic. You can use 'llvm.annotation' on +any integer bit width. +
++ declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> ) + declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> ) + declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> ) + declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> ) + declare i256 @llvm.annotation.i256(i256 <val>, i8* <str>, i8* <str>, i32 <int> ) ++ +
+The 'llvm.annotation' intrinsic. +
+ ++The first argument is an integer value (result of some expression), +the second is a pointer to a global string, the third is a pointer to a global +string which is the source file name, and the last argument is the line number. +It returns the value of the first argument. +
+ ++This intrinsic allows annotations to be put on arbitrary expressions +with arbitrary strings. This can be useful for special purpose optimizations +that want to look for these annotations. These have no other defined use, they +are ignored by code generation and optimization. +