<body>
-<div class="doc_title"> LLVM Language Reference Manual </div>
+<h1>LLVM Language Reference Manual</h1>
<ol>
<li><a href="#abstract">Abstract</a></li>
<li><a href="#introduction">Introduction</a></li>
<li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
<li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
<li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
+ <li><a href="#int_pow">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
+ <li><a href="#int_pow">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
</ol>
</li>
<li><a href="#int_manip">Bit Manipulation Intrinsics</a>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="abstract">Abstract </a></div>
+<h2><a name="abstract">Abstract</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>This document is a reference manual for the LLVM assembly language. LLVM is
a Static Single Assignment (SSA) based representation that provides type
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="introduction">Introduction</a> </div>
+<h2><a name="introduction">Introduction</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>The LLVM code representation is designed to be used in three different forms:
as an in-memory compiler IR, as an on-disk bitcode representation (suitable
variable is never accessed outside of the current function, allowing it to
be promoted to a simple SSA value instead of a memory location.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
+<h4>
+ <a name="wellformed">Well-Formedness</a>
+</h4>
-<div class="doc_text">
+<div>
<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
</div>
+</div>
+
<!-- Describe the typesetting conventions here. -->
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
+<h2><a name="identifiers">Identifiers</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>LLVM identifiers come in two basic types: global and local. Global
identifiers (functions, global variables) begin with the <tt>'@'</tt>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
+<h2><a name="highlevel">High Level Structure</a></h2>
<!-- *********************************************************************** -->
-
+<div>
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
-</div>
+<h3>
+ <a name="modulestructure">Module Structure</a>
+</h3>
-<div class="doc_text">
+<div>
<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,
<pre class="doc_code">
<i>; Declare the string constant as a global constant.</i>
-<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>
<a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
+<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>
<a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
<i>; External declaration of the puts function</i>
<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="linkage">Linkage Types</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>All Global Variables and Functions have one of the following types of
linkage:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="callingconv">Calling Conventions</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<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
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="visibility">Visibility Styles</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>All Global Variables and Functions have one of the following visibility
styles:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="namedtypes">Named Types</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM IR allows you to specify name aliases for certain types. This can make
it easier to read the IR and make the IR more condensed (particularly when
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="globalvars">Global Variables</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Global variables define regions of memory allocated at compilation time
instead of run-time. Global variables may optionally be initialized, may
region of memory, and all memory objects in LLVM are accessed through
pointers.</p>
+<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
+ that the address is not significant, only the content. Constants marked
+ like this can be merged with other constants if they have the same
+ initializer. Note that a constant with significant address <em>can</em>
+ be merged with a <tt>unnamed_addr</tt> constant, the result being a
+ constant whose address is significant.</p>
+
<p>A global variable may be declared to reside in a target-specific numbered
address space. For targets that support them, address spaces may affect how
optimizations are performed and/or what target instructions are used to
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="functionstructure">Functions</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
optional <a href="#linkage">linkage type</a>, an optional
<a href="#visibility">visibility style</a>, an optional
- <a href="#callingconv">calling convention</a>, a return type, an optional
+ <a href="#callingconv">calling convention</a>,
+ an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
<a href="#paramattrs">parameter attribute</a> for the return type, a function
name, a (possibly empty) argument list (each with optional
<a href="#paramattrs">parameter attributes</a>), optional
<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
optional <a href="#linkage">linkage type</a>, an optional
<a href="#visibility">visibility style</a>, an optional
- <a href="#callingconv">calling convention</a>, a return type, an optional
+ <a href="#callingconv">calling convention</a>,
+ an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
<a href="#paramattrs">parameter attribute</a> for the return type, a function
name, a possibly empty list of arguments, an optional alignment, and an
optional <a href="#gc">garbage collector name</a>.</p>
specified, the function is forced to have at least that much alignment. All
alignments must be a power of 2.</p>
+<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
+ be significant and two identical functions can be merged</p>.
+
<h5>Syntax:</h5>
<pre class="doc_code">
define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="aliasstructure">Aliases</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Aliases act as "second name" for the aliasee value (which can be either
function, global variable, another alias or bitcast of global value). Aliases
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="namedmetadatastructure">Named Metadata</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
nodes</a> (but not metadata strings) are the only valid operands for
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
+<h3>
+ <a name="paramattrs">Parameter Attributes</a>
+</h3>
-<div class="doc_text">
+<div>
<p>The return type and each parameter of a function type may have a set of
<i>parameter attributes</i> associated with them. Parameter attributes are
<dl>
<dt><tt><b>zeroext</b></tt></dt>
<dd>This indicates to the code generator that the parameter or return value
- should be zero-extended to a 32-bit value by the caller (for a parameter)
- or the callee (for a return value).</dd>
+ should be zero-extended to the extent required by the target's ABI (which
+ is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
+ parameter) or the callee (for a return value).</dd>
<dt><tt><b>signext</b></tt></dt>
<dd>This indicates to the code generator that the parameter or return value
- should be sign-extended to a 32-bit value by the caller (for a parameter)
- or the callee (for a return value).</dd>
+ should be sign-extended to the extent required by the target's ABI (which
+ is usually 32-bits) by the caller (for a parameter) or the callee (for a
+ return value).</dd>
<dt><tt><b>inreg</b></tt></dt>
<dd>This indicates that this parameter or return value should be treated in a
registers). Use of this attribute is target-specific.</dd>
<dt><tt><b><a name="byval">byval</a></b></tt></dt>
- <dd>This indicates that the pointer parameter should really be passed by value
- to the function. The attribute implies that a hidden copy of the pointee
+ <dd><p>This indicates that the pointer parameter should really be passed by
+ value to the function. The attribute implies that a hidden copy of the
+ pointee
is made between the caller and the callee, so the callee is unable to
modify the value in the callee. This attribute is only valid on LLVM
pointer arguments. It is generally used to pass structs and arrays by
to belong to the caller not the callee (for example,
<tt><a href="#readonly">readonly</a></tt> functions should not write to
<tt>byval</tt> parameters). This is not a valid attribute for return
- values. The byval attribute also supports specifying an alignment with
- the align attribute. This has a target-specific effect on the code
- generator that usually indicates a desired alignment for the synthesized
- stack slot.</dd>
+ values.</p>
+
+ <p>The byval attribute also supports specifying an alignment with
+ the align attribute. It indicates the alignment of the stack slot to
+ form and the known alignment of the pointer specified to the call site. If
+ the alignment is not specified, then the code generator makes a
+ target-specific assumption.</p></dd>
<dt><tt><b><a name="sret">sret</a></b></tt></dt>
<dd>This indicates that the pointer parameter specifies the address of a
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="gc">Garbage Collector Names</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Each function may specify a garbage collector name, which is simply a
string:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="fnattrs">Function Attributes</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Function attributes are set to communicate additional information about a
function. Function attributes are considered to be part of the function, not
threshold for this caller.</dd>
<dt><tt><b>hotpatch</b></tt></dt>
- <dd>This attribute indicates that the prologue should contain a 'hotpatch'
- sequence at the beginning. This is the same sequence used in the
- system DLLs in Microsoft Windows XP Service Pack 2 and higher.</dd>
+ <dd>This attribute indicates that the function should be 'hotpatchable',
+ meaning the function can be patched and/or hooked even while it is
+ loaded into memory. On x86, the function prologue will be preceded
+ by six bytes of padding and will begin with a two-byte instruction.
+ Most of the functions in the Windows system DLLs in Windows XP SP2 or
+ higher were compiled in this fashion.</dd>
<dt><tt><b>inlinehint</b></tt></dt>
<dd>This attribute indicates that the source code contained a hint that inlining
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="moduleasm">Module-Level Inline Assembly</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Modules may contain "module-level inline asm" blocks, which corresponds to
the GCC "file scope inline asm" blocks. These blocks are internally
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="datalayout">Data Layout</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>A module may specify a target specific data layout string that specifies how
data is to be laid out in memory. The syntax for the data layout is
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="pointeraliasing">Pointer Aliasing Rules</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Any memory access must be done through a pointer value associated
with an address range of the memory access, otherwise the behavior
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="volatile">Volatile Memory Accesses</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
href="#i_store"><tt>store</tt></a>s, and <a
</div>
+</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="typesystem">Type System</a> </div>
+<h2><a name="typesystem">Type System</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>The LLVM type system is one of the most important features of the
intermediate representation. Being typed enables a number of optimizations
and transformations that are not feasible to perform on normal three address
code representations.</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="t_classifications">Type
-Classifications</a> </div>
+<h3>
+ <a name="t_classifications">Type Classifications</a>
+</h3>
-<div class="doc_text">
+<div>
<p>The types fall into a few useful classifications:</p>
<td><a href="#t_primitive">primitive</a></td>
<td><a href="#t_label">label</a>,
<a href="#t_void">void</a>,
+ <a href="#t_integer">integer</a>,
<a href="#t_floating">floating point</a>,
<a href="#t_x86mmx">x86mmx</a>,
<a href="#t_metadata">metadata</a>.</td>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
+<h3>
+ <a name="t_primitive">Primitive Types</a>
+</h3>
-<div class="doc_text">
+<div>
<p>The primitive types are the fundamental building blocks of the LLVM
system.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
+<h4>
+ <a name="t_integer">Integer Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The integer type is a very simple type that simply specifies an arbitrary
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
+<h4>
+ <a name="t_floating">Floating Point Types</a>
+</h4>
-<div class="doc_text">
+<div>
<table>
<tbody>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
+<h4>
+ <a name="t_x86mmx">X86mmx Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
+<h4>
+ <a name="t_void">Void Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The void type does not represent any value and has no size.</p>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
+<h4>
+ <a name="t_label">Label Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The label type represents code labels.</p>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
+<h4>
+ <a name="t_metadata">Metadata Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The metadata type represents embedded metadata. No derived types may be
</div>
+</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
+<h3>
+ <a name="t_derived">Derived Types</a>
+</h3>
-<div class="doc_text">
+<div>
<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
of another array.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
+<h4>
+ <a name="t_aggregate">Aggregate Types</a>
+</h4>
-<div class="doc_text">
+<div>
<p>Aggregate Types are a subset of derived types that can contain multiple
member types. <a href="#t_array">Arrays</a>,
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
+<h4>
+ <a name="t_array">Array Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The array type is a very simple derived type that arranges elements
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
+<h4>
+ <a name="t_function">Function Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The function type can be thought of as a function signature. It consists of
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
+<h4>
+ <a name="t_struct">Structure Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The structure type is used to represent a collection of data members together
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
-</div>
+<h4>
+ <a name="t_pstruct">Packed Structure Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The packed structure type is used to represent a collection of data members
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
+<h4>
+ <a name="t_pointer">Pointer Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>The pointer type is used to specify memory locations.
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
+<h4>
+ <a name="t_vector">Vector Type</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>A vector type is a simple derived type that represents a vector of elements.
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
-<div class="doc_text">
+<h4>
+ <a name="t_opaque">Opaque Type</a>
+</h4>
+
+<div>
<h5>Overview:</h5>
<p>Opaque types are used to represent unknown types in the system. This
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="t_uprefs">Type Up-references</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<h5>Overview:</h5>
<p>An "up reference" allows you to refer to a lexically enclosing type without
</div>
+</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="constants">Constants</a> </div>
+<h2><a name="constants">Constants</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>LLVM has several different basic types of constants. This section describes
them all and their syntax.</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
+<h3>
+ <a name="simpleconstants">Simple Constants</a>
+</h3>
-<div class="doc_text">
+<div>
<dl>
<dt><b>Boolean constants</b></dt>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="aggregateconstants"></a> <!-- old anchor -->
<a name="complexconstants">Complex Constants</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Complex constants are a (potentially recursive) combination of simple
constants and smaller complex constants.</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="globalconstants">Global Variable and Function Addresses</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>The addresses of <a href="#globalvars">global variables</a>
and <a href="#functionstructure">functions</a> are always implicitly valid
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
-<div class="doc_text">
+<h3>
+ <a name="undefvalues">Undefined Values</a>
+</h3>
+
+<div>
<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
indicates that the user of the value may receive an unspecified bit-pattern.
- Undefined values may be of any type (other than label or void) and be used
- anywhere a constant is permitted.</p>
+ Undefined values may be of any type (other than '<tt>label</tt>'
+ or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
<p>Undefined values are useful because they indicate to the compiler that the
program is well defined no matter what value is used. This gives the
</pre>
<p>This is safe because all of the output bits are affected by the undef bits.
-Any output bit can have a zero or one depending on the input bits.</p>
+ Any output bit can have a zero or one depending on the input bits.</p>
<pre class="doc_code">
%A = or %X, undef
</pre>
<p>These logical operations have bits that are not always affected by the input.
-For example, if "%X" has a zero bit, then the output of the 'and' operation will
-always be a zero, no matter what the corresponding bit from the undef is. As
-such, it is unsafe to optimize or assume that the result of the and is undef.
-However, it is safe to assume that all bits of the undef could be 0, and
-optimize the and to 0. Likewise, it is safe to assume that all the bits of
-the undef operand to the or could be set, allowing the or to be folded to
--1.</p>
+ For example, if <tt>%X</tt> has a zero bit, then the output of the
+ '<tt>and</tt>' operation will always be a zero for that bit, no matter what
+ the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
+ optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
+ However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
+ 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
+ all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
+ set, allowing the '<tt>or</tt>' to be folded to -1.</p>
<pre class="doc_code">
%A = select undef, %X, %Y
%C = undef
</pre>
-<p>This set of examples show that undefined select (and conditional branch)
-conditions can go "either way" but they have to come from one of the two
-operands. In the %A example, if %X and %Y were both known to have a clear low
-bit, then %A would have to have a cleared low bit. However, in the %C example,
-the optimizer is allowed to assume that the undef operand could be the same as
-%Y, allowing the whole select to be eliminated.</p>
-
+<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
+ branch) conditions can go <em>either way</em>, but they have to come from one
+ of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
+ <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
+ have to have a cleared low bit. However, in the <tt>%C</tt> example, the
+ optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
+ same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
+ eliminated.</p>
<pre class="doc_code">
%A = xor undef, undef
%F = undef
</pre>
-<p>This example points out that two undef operands are not necessarily the same.
-This can be surprising to people (and also matches C semantics) where they
-assume that "X^X" is always zero, even if X is undef. This isn't true for a
-number of reasons, but the short answer is that an undef "variable" can
-arbitrarily change its value over its "live range". This is true because the
-"variable" doesn't actually <em>have a live range</em>. Instead, the value is
-logically read from arbitrary registers that happen to be around when needed,
-so the value is not necessarily consistent over time. In fact, %A and %C need
-to have the same semantics or the core LLVM "replace all uses with" concept
-would not hold.</p>
+<p>This example points out that two '<tt>undef</tt>' operands are not
+ necessarily the same. This can be surprising to people (and also matches C
+ semantics) where they assume that "<tt>X^X</tt>" is always zero, even
+ if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
+ short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
+ its value over its "live range". This is true because the variable doesn't
+ actually <em>have a live range</em>. Instead, the value is logically read
+ from arbitrary registers that happen to be around when needed, so the value
+ is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
+ need to have the same semantics or the core LLVM "replace all uses with"
+ concept would not hold.</p>
<pre class="doc_code">
%A = fdiv undef, %X
</pre>
<p>These examples show the crucial difference between an <em>undefined
-value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
-allowed to have an arbitrary bit-pattern. This means that the %A operation
-can be constant folded to undef because the undef could be an SNaN, and fdiv is
-not (currently) defined on SNaN's. However, in the second example, we can make
-a more aggressive assumption: because the undef is allowed to be an arbitrary
-value, we are allowed to assume that it could be zero. Since a divide by zero
-has <em>undefined behavior</em>, we are allowed to assume that the operation
-does not execute at all. This allows us to delete the divide and all code after
-it: since the undefined operation "can't happen", the optimizer can assume that
-it occurs in dead code.
-</p>
+ value</em> and <em>undefined behavior</em>. An undefined value (like
+ '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
+ the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
+ the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
+ defined on SNaN's. However, in the second example, we can make a more
+ aggressive assumption: because the <tt>undef</tt> is allowed to be an
+ arbitrary value, we are allowed to assume that it could be zero. Since a
+ divide by zero has <em>undefined behavior</em>, we are allowed to assume that
+ the operation does not execute at all. This allows us to delete the divide and
+ all code after it. Because the undefined operation "can't happen", the
+ optimizer can assume that it occurs in dead code.</p>
<pre class="doc_code">
a: store undef -> %X
b: unreachable
</pre>
-<p>These examples reiterate the fdiv example: a store "of" an undefined value
-can be assumed to not have any effect: we can assume that the value is
-overwritten with bits that happen to match what was already there. However, a
-store "to" an undefined location could clobber arbitrary memory, therefore, it
-has undefined behavior.</p>
+<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
+ undefined value can be assumed to not have any effect; we can assume that the
+ value is overwritten with bits that happen to match what was already there.
+ However, a store <em>to</em> an undefined location could clobber arbitrary
+ memory, therefore, it has undefined behavior.</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
-<div class="doc_text">
+<h3>
+ <a name="trapvalues">Trap Values</a>
+</h3>
+
+<div>
<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
instead of representing an unspecified bit pattern, they represent the
<a href="#terminators">terminator instruction</a>
if the terminator instruction has multiple successors and the instruction
is always executed when control transfers to one of the successors, and
- may not be executed when control is transfered to another.</li>
+ may not be executed when control is transferred to another.</li>
+
+<li>Additionally, an instruction also <i>control-depends</i> on a terminator
+ instruction if the set of instructions it otherwise depends on would be
+ different if the terminator had transferred control to a different
+ successor.</li>
<li>Dependence is transitive.</li>
%narrowaddr = bitcast i32* @g to i16*
%wideaddr = bitcast i32* @g to i64*
- %trap3 = load 16* %narrowaddr ; Returns a trap value.
- %trap4 = load i64* %widaddr ; Returns a trap value.
+ %trap3 = load i16* %narrowaddr ; Returns a trap value.
+ %trap4 = load i64* %wideaddr ; Returns a trap value.
- %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
- %br i1 %cmp, %true, %end ; Branch to either destination.
+ %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
+ br i1 %cmp, label %true, label %end ; Branch to either destination.
true:
volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
; control-dependent on %cmp, so this
; always results in a trap value.
- volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
- ; so this is defined (ignoring earlier
+ volatile store i32 0, i32* @g ; This would depend on the store in %true
+ ; if %cmp is true, or the store in %entry
+ ; otherwise, so this is undefined behavior.
+
+ br i1 %cmp, label %second_true, label %second_end
+ ; The same branch again, but this time the
+ ; true block doesn't have side effects.
+
+second_true:
+ ; No side effects!
+ ret void
+
+second_end:
+ volatile store i32 0, i32* @g ; This time, the instruction always depends
+ ; on the store in %end. Also, it is
+ ; control-equivalent to %end, so this is
+ ; well-defined (again, ignoring earlier
; undefined behavior in this example).
</pre>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
- Blocks</a></div>
-<div class="doc_text">
+<h3>
+ <a name="blockaddress">Addresses of Basic Blocks</a>
+</h3>
+
+<div>
<p><b><tt>blockaddress(@function, %block)</tt></b></p>
the address of the entry block is illegal.</p>
<p>This value only has defined behavior when used as an operand to the
- '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
- against null. Pointer equality tests between labels addresses is undefined
- behavior - though, again, comparison against null is ok, and no label is
- equal to the null pointer. This may also be passed around as an opaque
- pointer sized value as long as the bits are not inspected. This allows
- <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
- the original value is reconstituted before the <tt>indirectbr</tt>.</p>
+ '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
+ comparisons against null. Pointer equality tests between labels addresses
+ results in undefined behavior — though, again, comparison against null
+ is ok, and no label is equal to the null pointer. This may be passed around
+ as an opaque pointer sized value as long as the bits are not inspected. This
+ allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
+ long as the original value is reconstituted before the <tt>indirectbr</tt>
+ instruction.</p>
-<p>Finally, some targets may provide defined semantics when
- using the value as the operand to an inline assembly, but that is target
- specific.
- </p>
+<p>Finally, some targets may provide defined semantics when using the value as
+ the operand to an inline assembly, but that is target specific.</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
-</div>
+<h3>
+ <a name="constantexprs">Constant Expressions</a>
+</h3>
-<div class="doc_text">
+<div>
<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>
+ supported). The following is the syntax for constant expressions:</p>
<dl>
<dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
</div>
+</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
+<h2><a name="othervalues">Other Values</a></h2>
<!-- *********************************************************************** -->
-
+<div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="inlineasm">Inline Assembler Expressions</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM supports inline assembler expressions (as opposed
to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
documented here. Constraints on what can be done (e.g. duplication, moving,
etc need to be documented). This is probably best done by reference to
another document that covers inline asm from a holistic perspective.</p>
-</div>
-<div class="doc_subsubsection">
+<h4>
<a name="inlineasm_md">Inline Asm Metadata</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
- attached to it that contains a constant integer. If present, the code
- generator will use the integer as the location cookie value when report
+ attached to it that contains a list of constant integers. If present, the
+ code generator will use the integer as the location cookie value when report
errors through the LLVMContext error reporting mechanisms. This allows a
front-end to correlate backend errors that occur with inline asm back to the
source code that produced it. For example:</p>
</pre>
<p>It is up to the front-end to make sense of the magic numbers it places in the
- IR.</p>
+ IR. If the MDNode contains multiple constants, the code generator will use
+ the one that corresponds to the line of the asm that the error occurs on.</p>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
- Strings</a>
</div>
-<div class="doc_text">
+<!-- ======================================================================= -->
+<h3>
+ <a name="metadata">Metadata Nodes and Metadata Strings</a>
+</h3>
+
+<div>
<p>LLVM IR allows metadata to be attached to instructions in the program that
can convey extra information about the code to the optimizers and code
<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
function is using two metadata arguments.</p>
- <pre class="doc_code">
- call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
- </pre>
+<div class="doc_code">
+<pre>
+call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
+</pre>
+</div>
<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
- <pre class="doc_code">
- %indvar.next = add i64 %indvar, 1, !dbg !21
- </pre>
+<div class="doc_code">
+<pre>
+%indvar.next = add i64 %indvar, 1, !dbg !21
+</pre>
+</div>
+
</div>
+</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
+<h2>
<a name="intrinsic_globals">Intrinsic Global Variables</a>
-</div>
+</h2>
<!-- *********************************************************************** -->
-
+<div>
<p>LLVM has a number of "magic" global variables that contain data that affect
code generation or other IR semantics. These are documented here. All globals
of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
by LLVM.</p>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
href="#linkage_appending">appending linkage</a>. This array contains a list of
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
-<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
-</div>
+<h3>
+ <a name="intg_compiler_used">
+ The '<tt>llvm.compiler.used</tt>' Global Variable
+ </a>
+</h3>
-<div class="doc_text">
+<div>
<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<pre>
%0 = type { i32, void ()* }
@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<pre>
%0 = type { i32, void ()* }
@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
</div>
+</div>
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
+<h2><a name="instref">Instruction Reference</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>The LLVM instruction set consists of several different classifications of
instructions: <a href="#terminators">terminator
<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>
+<h3>
+ <a name="terminators">Terminator Instructions</a>
+</h3>
-<div class="doc_text">
+<div>
<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
in a program ends with a "Terminator" instruction, which indicates which
'<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
'<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_ret">'<tt>ret</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
+<h4>
+ <a name="i_br">'<tt>br</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_switch">'<tt>switch</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
+<h3>
+ <a name="binaryops">Binary Operations</a>
+</h3>
-<div class="doc_text">
+<div>
<p>Binary operators are used to do most of the computation in a program. They
require two operands of the same type, execute an operation on them, and
<p>There are several different binary operators:</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_add">'<tt>add</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_sub">'<tt>sub</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_mul">'<tt>mul</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
-</a></div>
+<h4>
+ <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
- <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = udiv exact <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
<p>Division by zero leads to undefined behavior.</p>
+<p>If the <tt>exact</tt> keyword is present, the result value of the
+ <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
+ multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
+
+
<h5>Example:</h5>
<pre>
<result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
-</a> </div>
+<h4>
+ <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
-</div>
+<h4>
+ <a name="i_urem">'<tt>urem</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_srem">'<tt>srem</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
<h5>Semantics:</h5>
<p>This instruction returns the <i>remainder</i> of a division (where the result
- has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
- operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
- a value. For more information about the difference,
+ is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
+ <i>modulo</i> operator (where the result is either zero or has the same sign
+ as the divisor, <tt>op2</tt>) of a value.
+ For more information about the difference,
see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Math Forum</a>. For a table of how this is implemented in various languages,
please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
+<h4>
+ <a name="i_frem">'<tt>frem</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
-Operations</a> </div>
+<h3>
+ <a name="bitwiseops">Bitwise Binary Operations</a>
+</h3>
-<div class="doc_text">
+<div>
<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
same type, execute an operation on them, and produce a single value. The
resulting value is the same type as its operands.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_shl">'<tt>shl</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
- <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = shl nuw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = shl nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = shl nuw nsw <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
shift amount in <tt>op2</tt>.</p>
+<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
+ <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
+ the <tt>nsw</tt> keyword is present, then the shift produces a
+ <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
+ with the resultant sign bit. As such, NUW/NSW have the same semantics as
+ they would if the shift were expressed as a mul instruction with the same
+ nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
+
<h5>Example:</h5>
<pre>
<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
- <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = lshr exact <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
shift amount in <tt>op2</tt>.</p>
+<p>If the <tt>exact</tt> keyword is present, the result value of the
+ <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
+ shifted out are non-zero.</p>
+
+
<h5>Example:</h5>
<pre>
<result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
-Instruction</a> </div>
-<div class="doc_text">
+<h4>
+ <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
- <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
+ <result> = ashr exact <ty> <op1>, <op2> <i>; yields {ty}:result</i>
</pre>
<h5>Overview:</h5>
the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
the corresponding shift amount in <tt>op2</tt>.</p>
+<p>If the <tt>exact</tt> keyword is present, the result value of the
+ <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
+ shifted out are non-zero.</p>
+
<h5>Example:</h5>
<pre>
<result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_and">'<tt>and</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
+<h4>
+ <a name="i_or">'<tt>or</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_xor">'<tt>xor</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="vectorops">Vector Operations</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM supports several instructions to represent vector operations in a
target-independent manner. These instructions cover the element-access and
will want to use target-specific intrinsics to take full advantage of a
specific target.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="aggregateops">Aggregate Operations</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM supports several instructions for working with
<a href="#t_aggregate">aggregate</a> values.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
<a href="#t_array">array</a> type. The operands are constant indices to
specify which value to extract in a similar manner as indices in a
'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
+ <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
+ <ul>
+ <li>Since the value being indexed is not a pointer, the first index is
+ omitted and assumed to be zero.</li>
+ <li>At least one index must be specified.</li>
+ <li>Not only struct indices but also array indices must be in
+ bounds.</li>
+ </ul>
<h5>Semantics:</h5>
<p>The result is the value at the position in the aggregate specified by the
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
- <result> = insertvalue <aggregate type> <val>, <ty> <elt>, <idx> <i>; yields <aggregate type></i>
+ <result> = insertvalue <aggregate type> <val>, <ty> <elt>, <idx>{, <idx>}* <i>; yields <aggregate type></i>
</pre>
<h5>Overview:</h5>
<a href="#t_array">array</a> type. The second operand is a first-class
value to insert. The following operands are constant indices indicating
the position at which to insert the value in a similar manner as indices in a
- '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
+ '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
value to insert must have the same type as the value identified by the
indices.</p>
<h5>Example:</h5>
<pre>
- %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
- %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
+ %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
+ %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
+ %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
</pre>
</div>
+</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="memoryops">Memory Access and Addressing Operations</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>A key design point of an SSA-based representation is how it represents
memory. In LLVM, no memory locations are in SSA form, which makes things
very simple. This section describes how to read, write, and allocate
memory in LLVM.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_load">'<tt>load</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
-Instruction</a> </div>
+<h4>
+ <a name="i_store">'<tt>store</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
</div>
-<div class="doc_text">
+<!-- ======================================================================= -->
+<h3>
+ <a name="convertops">Conversion Operations</a>
+</h3>
+
+<div>
<p>The instructions in this category are the conversion instructions (casting)
which all take a single operand and a type. They perform various bit
conversions on the operand.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
- be an <a href="#t_integer">integer</a> type, and a type that specifies the
- size and type of the result, which must be
- an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
- be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
- allowed.</p>
+<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
+ Both types must be of <a href="#t_integer">integer</a> types, or vectors
+ of the same number of integers.
+ The bit size of the <tt>value</tt> must be larger than
+ the bit size of the destination type, <tt>ty2</tt>.
+ Equal sized types are not allowed.</p>
<h5>Semantics:</h5>
<p>The '<tt>trunc</tt>' instruction truncates the high order bits
<h5>Example:</h5>
<pre>
- %X = trunc i32 257 to i8 <i>; yields i8:1</i>
- %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
- %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
+ %X = trunc i32 257 to i8 <i>; yields i8:1</i>
+ %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
+ %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
+ %W = trunc <2 x i16> <i16 8, i16 7> to <2 x i8> <i>; yields <i8 8, i8 7></i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
<h5>Arguments:</h5>
-<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
- <a href="#t_integer">integer</a> type, and a type to cast it to, which must
- also be of <a href="#t_integer">integer</a> type. The bit size of the
- <tt>value</tt> must be smaller than the bit size of the destination type,
+<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
+ Both types must be of <a href="#t_integer">integer</a> types, or vectors
+ of the same number of integers.
+ The bit size of the <tt>value</tt> must be smaller than
+ the bit size of the destination type,
<tt>ty2</tt>.</p>
<h5>Semantics:</h5>
<pre>
%X = zext i32 257 to i64 <i>; yields i64:257</i>
%Y = zext i1 true to i32 <i>; yields i32:1</i>
+ %Z = zext <2 x i16> <i16 8, i16 7> to <2 x i32> <i>; yields <i32 8, i32 7></i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
-<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
- <a href="#t_integer">integer</a> type, and a type to cast it to, which must
- also be of <a href="#t_integer">integer</a> type. The bit size of the
- <tt>value</tt> must be smaller than the bit size of the destination type,
+<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
+ Both types must be of <a href="#t_integer">integer</a> types, or vectors
+ of the same number of integers.
+ The bit size of the <tt>value</tt> must be smaller than
+ the bit size of the destination type,
<tt>ty2</tt>.</p>
<h5>Semantics:</h5>
<pre>
%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
%Y = sext i1 true to i32 <i>; yields i32:-1</i>
+ %Z = sext <2 x i16> <i16 8, i16 7> to <2 x i32> <i>; yields <i32 8, i32 7></i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
<h5>Example:</h5>
<pre>
- %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
- %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
+ %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
+ %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
+<h3>
+ <a name="otherops">Other Operations</a>
+</h3>
-<div class="doc_text">
+<div>
<p>The instructions in this category are the "miscellaneous" instructions, which
defy better classification.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
-</div>
+<h4>
+ <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
-</div>
+<h4>
+ <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_phi">'<tt>phi</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_select">'<tt>select</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_call">'<tt>call</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
+</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
+<h2><a name="intrinsics">Intrinsic Functions</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>LLVM supports the notion of an "intrinsic function". These functions have
well known names and semantics and are required to follow certain
<p>To learn how to add an intrinsic function, please see the
<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_varargs">Variable Argument Handling Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Variable argument support is defined in LLVM with
the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
declare void @llvm.va_end(i8*)
</pre>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_gc">Accurate Garbage Collection Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Collection</a> (GC) requires the implementation and generation of these
<p>The garbage collection intrinsics only operate on objects in the generic
address space (address space zero).</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_codegen">Code Generator Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>These intrinsics are provided by LLVM to expose special features that may
only be implemented with code generator support.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_libc">Standard C Library Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM provides intrinsics for a few important standard C library functions.
These intrinsics allow source-language front-ends to pass information about
the alignment of the pointer arguments to the code generator, providing
opportunity for more efficient code generation.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
</div>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<h4>
+ <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
+</h4>
+
+<div>
+
+<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
+<pre>
+ declare float @llvm.exp.f32(float %Val)
+ declare double @llvm.exp.f64(double %Val)
+ declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
+ declare fp128 @llvm.exp.f128(fp128 %Val)
+ declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
+
+<h5>Arguments:</h5>
+<p>The argument and return value are floating point numbers of the same
+ type.</p>
+
+<h5>Semantics:</h5>
+<p>This function returns the same values as the libm <tt>exp</tt> functions
+ would, and handles error conditions in the same way.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<h4>
+ <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
+</h4>
+
+<div>
+
+<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
+ floating point or vector of floating point type. Not all targets support all
+ types however.</p>
+
+<pre>
+ declare float @llvm.log.f32(float %Val)
+ declare double @llvm.log.f64(double %Val)
+ declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
+ declare fp128 @llvm.log.f128(fp128 %Val)
+ declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
+
+<h5>Arguments:</h5>
+<p>The argument and return value are floating point numbers of the same
+ type.</p>
+
+<h5>Semantics:</h5>
+<p>This function returns the same values as the libm <tt>log</tt> functions
+ would, and handles error conditions in the same way.</p>
+
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_manip">Bit Manipulation Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM provides intrinsics for a few important bit manipulation operations.
These allow efficient code generation for some algorithms.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic function. You can use bswap on any integer
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
-</div>
+<h4>
+ <a name="int_sadd_overflow">
+ '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
-</div>
+<h4>
+ <a name="int_uadd_overflow">
+ '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
-</div>
+<h4>
+ <a name="int_ssub_overflow">
+ '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
-</div>
+<h4>
+ <a name="int_usub_overflow">
+ '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
-</div>
+<h4>
+ <a name="int_smul_overflow">
+ '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
-</div>
+<h4>
+ <a name="int_umul_overflow">
+ '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_fp16">Half Precision Floating Point Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Half precision floating point is a storage-only format. This means that it is
a dense encoding (in memory) but does not support computation in the
float if needed, then converted to i16 with
<a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
storing as an i16 value.</p>
-</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
-</div>
+<h4>
+ <a name="int_convert_to_fp16">
+ '<tt>llvm.convert.to.fp16</tt>' Intrinsic
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
-</div>
+<h4>
+ <a name="int_convert_from_fp16">
+ '<tt>llvm.convert.from.fp16</tt>' Intrinsic
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_debugger">Debugger Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
prefix), are described in
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_eh">Exception Handling Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>The LLVM exception handling intrinsics (which all start with
<tt>llvm.eh.</tt> prefix), are described in
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_trampoline">Trampoline Intrinsic</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>This intrinsic makes it possible to excise one parameter, marked with
the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
-</div>
+<h4>
+ <a name="int_it">
+ '<tt>llvm.init.trampoline</tt>' Intrinsic
+ </a>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>These intrinsic functions expand the "universal IR" of LLVM to represent
hardware constructs for atomic operations and memory synchronization. This
No one model or paradigm should be selected above others unless the hardware
itself ubiquitously does so.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<pre>
declare void @llvm.memory.barrier(i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>, i1 <device>)
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
-</div>
-<div class="doc_text">
+</h4>
+
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
+</h4>
-</div>
-
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
+</h4>
-</div>
-
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
- <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
- <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
- <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
-</div>
-
-<div class="doc_text">
+<h4>
+ <a name="int_atomic_load_and">
+ '<tt>llvm.atomic.load.and.*</tt>' Intrinsic
+ </a>
+ <br>
+ <a name="int_atomic_load_nand">
+ '<tt>llvm.atomic.load.nand.*</tt>' Intrinsic
+ </a>
+ <br>
+ <a name="int_atomic_load_or">
+ '<tt>llvm.atomic.load.or.*</tt>' Intrinsic
+ </a>
+ <br>
+ <a name="int_atomic_load_xor">
+ '<tt>llvm.atomic.load.xor.*</tt>' Intrinsic
+ </a>
+</h4>
+
+<div>
<h5>Syntax:</h5>
<p>These are overloaded intrinsics. You can
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
- <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
- <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
- <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
-</div>
-
-<div class="doc_text">
+<h4>
+ <a name="int_atomic_load_max">
+ '<tt>llvm.atomic.load.max.*</tt>' Intrinsic
+ </a>
+ <br>
+ <a name="int_atomic_load_min">
+ '<tt>llvm.atomic.load.min.*</tt>' Intrinsic
+ </a>
+ <br>
+ <a name="int_atomic_load_umax">
+ '<tt>llvm.atomic.load.umax.*</tt>' Intrinsic
+ </a>
+ <br>
+ <a name="int_atomic_load_umin">
+ '<tt>llvm.atomic.load.umin.*</tt>' Intrinsic
+ </a>
+</h4>
+
+<div>
<h5>Syntax:</h5>
<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
</div>
+</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_memorymarkers">Memory Use Markers</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>This class of intrinsics exists to information about the lifetime of memory
objects and ranges where variables are immutable.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
- declare {}* @llvm.invariant.start(i64 <size>, i8* nocapture <ptr>) readonly
+ declare {}* @llvm.invariant.start(i64 <size>, i8* nocapture <ptr>)
</pre>
<h5>Overview:</h5>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
+</div>
+
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="int_general">General Intrinsics</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>This class of intrinsics is designed to be generic and has no specific
purpose.</p>
-</div>
-
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
the <tt>AllocaInst</tt> stack slot to be before local variables on the
stack. This is to ensure that if a local variable on the stack is
overwritten, it will destroy the value of the guard. When the function exits,
- the guard on the stack is checked against the original guard. If they're
+ the guard on the stack is checked against the original guard. If they are
different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
function.</p>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
+<h4>
<a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
-</div>
+</h4>
-<div class="doc_text">
+<div>
<h5>Syntax:</h5>
<pre>
</pre>
<h5>Overview:</h5>
-<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
- to the optimizers to discover at compile time either a) when an
- operation like memcpy will either overflow a buffer that corresponds to
- an object, or b) to determine that a runtime check for overflow isn't
- necessary. An object in this context means an allocation of a
- specific class, structure, array, or other object.</p>
+<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
+ the optimizers to determine at compile time whether a) an operation (like
+ memcpy) will overflow a buffer that corresponds to an object, or b) that a
+ runtime check for overflow isn't necessary. An object in this context means
+ an allocation of a specific class, structure, array, or other object.</p>
<h5>Arguments:</h5>
-<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
+<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
argument is a pointer to or into the <tt>object</tt>. The second argument
- is a boolean 0 or 1. This argument determines whether you want the
- maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
+ is a boolean 0 or 1. This argument determines whether you want the
+ maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
1, variables are not allowed.</p>
<h5>Semantics:</h5>
<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
- representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
- (depending on the <tt>type</tt> argument if the size cannot be determined
- at compile time.</p>
+ representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
+ depending on the <tt>type</tt> argument, if the size cannot be determined at
+ compile time.</p>
+
+</div>
+
+</div>
</div>
src="http://www.w3.org/Icons/valid-html401-blue" 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>
+ <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
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