<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>
+ <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
</ol>
</li>
</ol>
</li>
<li><a href="#int_atomics">Atomic intrinsics</a>
<ol>
- <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></li>
+ <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
+ <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
+ <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
+ <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
</ol>
</li>
<li><a href="#int_general">General intrinsics</a>
</div>
<div class="doc_text">
<p>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 <a href="#linkage">linkage type</a>, and an
+ function, global variable, another alias or bitcast of global value). Aliases
+
may have an optional <a href="#linkage">linkage type</a>, and an
optional <a href="#visibility">visibility style</a>.</p>
<h5>Syntax:</h5>
value, but is also valid on scalars (even though this is silly).</dd>
<dt><tt>sret</tt></dt>
- <dd>This indicates that the parameter specifies the address of a structure
- that is the return value of the function in the source program.</dd>
+ <dd>This indicates that the pointer parameter specifies the address of a
+ structure that is the return value of the function in the source program.
+ Loads and stores to the structure are assumed not to trap.
+ May only be applied to the first parameter.</dd>
<dt><tt>noalias</tt></dt>
<dd>This indicates that the parameter does not alias any global or any other
an <tt>unreachable</tt> instruction immediately followed the call.</dd>
<dt><tt>nounwind</tt></dt>
- <dd>This function attribute indicates that the function type does not use
- the unwind instruction and does not allow stack unwinding to propagate
- through it.</dd>
-
+ <dd>This function attribute indicates that no exceptions unwind out of the
+ function. Usually this is because the function makes no use of exceptions,
+ but it may also be that the function catches any exceptions thrown when
+ executing it.</dd>
+
<dt><tt>nest</tt></dt>
<dd>This indicates that the parameter can be excised using the
<a href="#int_trampoline">trampoline intrinsics</a>.</dd>
<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
+consists of a return type and a list of formal parameter types. The
+return type of a function type is a scalar type or a void type or a struct type.
+If the return type is a struct type then all struct elements must be of first
+class types. 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>
+<pre> <returntype list> (<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>
+ href="#int_varargs">variable argument handling intrinsic</a> functions.
+'<tt><returntype list></tt>' is a comma-separated list of
+<a href="#t_firstclass">first class</a> type specifiers.</p>
<h5>Examples:</h5>
<table class="layout">
<tr class="layout">
which returns an integer. This is the signature for <tt>printf</tt> in
LLVM.
</td>
+ </tr><tr class="layout">
+ <td class="left"><tt>{i32, i32} (i32)</tt></td>
+ <td class="left">A function taking an <tt>i32></tt>, returning two
+ <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
+ </td>
</tr>
</table>
<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>
+ notation (see below). The assembler requires the exact decimal value of
+ a floating-point constant. For example, the assembler accepts 1.25 but
+ rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
+ constants must have a <a href="#t_floating">floating point</a> type. </dd>
<dt><b>Null pointer constants</b></dt>
<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>
+ ret <type> <value>, <type> <value> <i>; Return two values from a non-void function </i>
</pre>
<h5>Overview:</h5>
<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
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>
+<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
+type of each return value must be a '<a href="#t_firstclass">first class</a>'
+ type. Note 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 values that do 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_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>
+return value. If the instruction returns multiple values then these
+values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
+</a>' instruction.</p>
<h5>Example:</h5>
<pre> ret i32 5 <i>; Return an integer value of 5</i>
ret void <i>; Return from a void function</i>
+ ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
<h5>Syntax:</h5>
<pre>
- <result> = invoke [<a href="#callingconv">cconv</a>] <ptr to function ty> %<function ptr val>(<function args>)
+ <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>
"<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>
+continued at the dynamically nearest "exception" label. If the callee function
+returns multiple values then individual return values are only accessible through
+a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
<h5>Arguments:</h5>
<h5>Example:</h5>
<pre>
- %retval = invoke i32 %Test(i32 15) to label %Continue
+ %retval = invoke i32 @Test(i32 15) to label %Continue
unwind label %TestCleanup <i>; {i32}:retval set</i>
- %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
+ %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
unwind label %TestCleanup <i>; {i32}:retval set</i>
</pre>
</div>
<div 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
+program. They require two operands of the same type, execute an operation on them, and
produce a single value. The operands might represent
multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
-The result value of a binary operator is not
-necessarily the same type as its operands.</p>
+The result value has the same type as its operands.</p>
<p>There are several different binary operators:</p>
</div>
<!-- _______________________________________________________________________ -->
types. This instruction can also take <a href="#t_vector">vector</a> versions
of the values in which case the elements must be integers.</p>
<h5>Semantics:</h5>
-<p>The value produced is the signed integer quotient of the two operands.</p>
+<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
<p>Note that signed integer division and unsigned integer division are distinct
operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
<p>Division by zero leads to undefined behavior. Overflow also leads to
of the values in which case the elements must be integers.</p>
<h5>Semantics:</h5>
<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
-This instruction always performs an unsigned division to get the remainder,
-regardless of whether the arguments are unsigned or not.</p>
+This instruction always performs an unsigned division to get the remainder.</p>
<p>Note that unsigned integer remainder and signed integer remainder are
distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
identical types. This instruction can also take <a href="#t_vector">vector</a>
versions of floating point values.</p>
<h5>Semantics:</h5>
-<p>This instruction returns the <i>remainder</i> of a division.</p>
+<p>This instruction returns the <i>remainder</i> of a division.
+The remainder has the same sign as the dividend.</p>
<h5>Example:</h5>
<pre> <result> = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
</pre>
<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>
+instructions. They require two operands of the same type, execute an operation on them,
+and produce a single value. The resulting value is the same type as its operands.</p>
</div>
<!-- _______________________________________________________________________ -->
<h5>Semantics:</h5>
-<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
-<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
-of bits in <tt>var1</tt>, the result is undefined.</p>
+<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
+where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
+equal to or larger than the number of bits in <tt>var1</tt>, the result is undefined.</p>
<h5>Example:</h5><pre>
<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
bytes of memory from the operating system and returns a pointer of the
appropriate type to the program. If "NumElements" is specified, it is the
number of elements allocated, otherwise "NumElements" is defaulted to be one.
-If an alignment is specified, the value result of the allocation is guaranteed to
+If a constant alignment is specified, the value result of the allocation is guaranteed to
be aligned to at least that boundary. If not specified, or if zero, the target can
choose to align the allocation on any convenient boundary.</p>
<h5>Semantics:</h5>
<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
-a pointer is returned.</p>
+a pointer is returned. Allocating zero bytes is undefined. The result is null
+if there is insufficient memory available.</p>
<h5>Example:</h5>
<h5>Semantics:</h5>
<p>Access to the memory pointed to by the pointer is no longer defined
-after this instruction executes.</p>
+after this instruction executes. If the pointer is null, the result is
+undefined.</p>
<h5>Example:</h5>
bytes of memory on the runtime stack, returning a pointer of the
appropriate type to the program. If "NumElements" is specified, it is the
number of elements allocated, otherwise "NumElements" is defaulted to be one.
-If an alignment is specified, the value result of the allocation is guaranteed
+If a constant alignment is specified, the value result of the allocation is guaranteed
to be aligned to at least that boundary. If not specified, or if zero, the target
can choose to align the allocation on any convenient boundary.</p>
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>
+instructions), the memory is reclaimed. Allocating zero bytes
+is legal, but the result is undefined.</p>
<h5>Example:</h5>
volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
instructions. </p>
<p>
-The optional "align" argument specifies the alignment of the operation
+The optional constant "align" argument specifies the alignment of the operation
(that is, the alignment of the memory address). A value of 0 or an
omitted "align" argument means that the operation has the preferential
alignment for the target. It is the responsibility of the code emitter
<h5>Arguments:</h5>
<p>There are two arguments to the '<tt>store</tt>' instruction: a value
to store and an address at which to store it. The type of the '<tt><pointer></tt>'
-operand must be a pointer to the type of the '<tt><value></tt>'
+operand must be a pointer to the <a href="#t_firstclass">first class</a> type
+of the '<tt><value></tt>'
operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
optimizer is not allowed to modify the number or order of execution of
this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
href="#i_store">store</a></tt> instructions.</p>
<p>
-The optional "align" argument specifies the alignment of the operation
+The optional constant "align" argument specifies the alignment of the operation
(that is, the alignment of the memory address). A value of 0 or an
omitted "align" argument means that the operation has the preferential
alignment for the target. It is the responsibility of the code emitter
on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
<a href="#t_integer">integer</a> type but the value will always be sign extended
-to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
-<b>constants</b>.</p>
+to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
+structure</a> types require <tt>i32</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>{ i32, double, %RT
</pre>
<h5>Overview:</h5>
<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
-of its two integer operands.</p>
+of its two integer or pointer operands.</p>
<h5>Arguments:</h5>
<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
the condition code indicating the kind of comparison to perform. It is not
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>
+function is bound to the result argument. If the callee returns multiple
+values then the return values of the function are only accessible through
+the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
<h5>Example:</h5>
<pre>
%retval = call i32 @test(i32 %argc)
- call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
- %X = tail call i32 @foo()
- %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
- %Z = call void %foo(i8 97 signext)
+ call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
+ %X = tail call i32 @foo() <i>; yields i32</i>
+ %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
+ call void %foo(i8 97 signext)
+
+ %struct.A = type { i32, i8 }
+ %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
+ %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
+ %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
</pre>
</div>
</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ <resultval> = getresult <type> <retval>, <index>
+</pre>
+
+<h5>Overview:</h5>
+
+<p> The '<tt>getresult</tt>' instruction is used to extract individual values
+from a '<tt><a href="#i_call">call</a></tt>'
+or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
+results.</p>
+
+<h5>Arguments:</h5>
+
+<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
+first argument. The value must have <a href="#t_struct">structure type</a>.
+The second argument is a constant unsigned index value which must be in range for
+the number of values returned by the call.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>getresult</tt>' instruction extracts the element identified by
+'<tt>index</tt>' from the aggregate value.</p>
+
+<h5>Example:</h5>
+
+<pre>
+ %struct.A = type { i32, i8 }
+
+ %r = call %struct.A @foo()
+ %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
+ %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
+ add i32 %gr, 42
+ add i8 %gr1, 41
+</pre>
+
+</div>
+
<!-- *********************************************************************** -->
<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
<!-- *********************************************************************** -->
</pre>
</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<p>
+ This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+
+<pre>
+declare i8 @llvm.atomic.lcs.i8( i8* <ptr>, i8 <cmp>, i8 <val> )
+declare i16 @llvm.atomic.lcs.i16( i16* <ptr>, i16 <cmp>, i16 <val> )
+declare i32 @llvm.atomic.lcs.i32( i32* <ptr>, i32 <cmp>, i32 <val> )
+declare i64 @llvm.atomic.lcs.i64( i64* <ptr>, i64 <cmp>, i64 <val> )
+
+</pre>
+<h5>Overview:</h5>
+<p>
+ This loads a value in memory and compares it to a given value. If they are
+ equal, it stores a new value into the memory.
+</p>
+<h5>Arguments:</h5>
+<p>
+ The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
+ well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
+ same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
+ this integer type. While any bit width integer may be used, targets may only
+ lower representations they support in hardware.
+
+</p>
+<h5>Semantics:</h5>
+<p>
+ This entire intrinsic must be executed atomically. It first loads the value
+ in memory pointed to by <tt>ptr</tt> and compares it with the value
+ <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
+ loaded value is yielded in all cases. This provides the equivalent of an
+ atomic compare-and-swap operation within the SSA framework.
+</p>
+<h5>Examples:</h5>
+
+<pre>
+%ptr = malloc i32
+ store i32 4, %ptr
+
+%val1 = add i32 4, 4
+%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
+ <i>; yields {i32}:result1 = 4</i>
+%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
+%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
+
+%val2 = add i32 1, 1
+%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
+ <i>; yields {i32}:result2 = 8</i>
+%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
+
+%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
+</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+
+<p>
+ This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+<pre>
+declare i8 @llvm.atomic.swap.i8( i8* <ptr>, i8 <val> )
+declare i16 @llvm.atomic.swap.i16( i16* <ptr>, i16 <val> )
+declare i32 @llvm.atomic.swap.i32( i32* <ptr>, i32 <val> )
+declare i64 @llvm.atomic.swap.i64( i64* <ptr>, i64 <val> )
+
+</pre>
+<h5>Overview:</h5>
+<p>
+ This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
+ the value from memory. It then stores the value in <tt>val</tt> in the memory
+ at <tt>ptr</tt>.
+</p>
+<h5>Arguments:</h5>
+
+<p>
+ The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
+ <tt>val</tt> argument and the result must be integers of the same bit width.
+ The first argument, <tt>ptr</tt>, must be a pointer to a value of this
+ integer type. The targets may only lower integer representations they
+ support.
+</p>
+<h5>Semantics:</h5>
+<p>
+ This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
+ stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
+ equivalent of an atomic swap operation within the SSA framework.
+
+</p>
+<h5>Examples:</h5>
+<pre>
+%ptr = malloc i32
+ store i32 4, %ptr
+
+%val1 = add i32 4, 4
+%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
+ <i>; yields {i32}:result1 = 4</i>
+%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
+%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
+
+%val2 = add i32 1, 1
+%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
+ <i>; yields {i32}:result2 = 8</i>
+
+%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
+%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
+</pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
+
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<p>
+ This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
+ integer bit width. Not all targets support all bit widths however.</p>
+<pre>
+declare i8 @llvm.atomic.las.i8.( i8* <ptr>, i8 <delta> )
+declare i16 @llvm.atomic.las.i16.( i16* <ptr>, i16 <delta> )
+declare i32 @llvm.atomic.las.i32.( i32* <ptr>, i32 <delta> )
+declare i64 @llvm.atomic.las.i64.( i64* <ptr>, i64 <delta> )
+
+</pre>
+<h5>Overview:</h5>
+<p>
+ This intrinsic adds <tt>delta</tt> to the value stored in memory at
+ <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
+</p>
+<h5>Arguments:</h5>
+<p>
+
+ The intrinsic takes two arguments, the first a pointer to an integer value
+ and the second an integer value. The result is also an integer value. These
+ integer types can have any bit width, but they must all have the same bit
+ width. The targets may only lower integer representations they support.
+</p>
+<h5>Semantics:</h5>
+<p>
+ This intrinsic does a series of operations atomically. It first loads the
+ value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
+ to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
+</p>
+
+<h5>Examples:</h5>
+<pre>
+%ptr = malloc i32
+ store i32 4, %ptr
+%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
+ <i>; yields {i32}:result1 = 4</i>
+%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
+ <i>; yields {i32}:result2 = 8</i>
+%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
+ <i>; yields {i32}:result3 = 10</i>
+%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
+</pre>
+</div>
+
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