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Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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				5	<title>LLVM Assembly Language Reference Manual</title>
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				7	<meta name="author" content="Chris Lattner">
				8	<meta name="description"
				9	content="LLVM Assembly Language Reference Manual.">
				10	<link rel="stylesheet" href="llvm.css" type="text/css">
				11	</head>
				12
				13	<body>
				14
				15	<div class="doc_title"> LLVM Language Reference Manual </div>
				16	<ol>
				17	<li><a href="#abstract">Abstract</a></li>
				18	<li><a href="#introduction">Introduction</a></li>
				19	<li><a href="#identifiers">Identifiers</a></li>
				20	<li><a href="#highlevel">High Level Structure</a>
				21	<ol>
				22	<li><a href="#modulestructure">Module Structure</a></li>
				23	<li><a href="#linkage">Linkage Types</a></li>
				24	<li><a href="#callingconv">Calling Conventions</a></li>
				25	<li><a href="#globalvars">Global Variables</a></li>
				26	<li><a href="#functionstructure">Functions</a></li>
				27	<li><a href="#aliasstructure">Aliases</a>
				28	<li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	29	<li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	30	<li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	31	<li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
				32	<li><a href="#datalayout">Data Layout</a></li>
				33	</ol>
				34	</li>
				35	<li><a href="#typesystem">Type System</a>
				36	<ol>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	37	<li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	38	<li><a href="#t_primitive">Primitive Types</a>
				39	<ol>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	40	<li><a href="#t_floating">Floating Point Types</a></li>
				41	<li><a href="#t_void">Void Type</a></li>
				42	<li><a href="#t_label">Label Type</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	43	</ol>
				44	</li>
				45	<li><a href="#t_derived">Derived Types</a>
				46	<ol>
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	47	<li><a href="#t_integer">Integer Type</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	48	<li><a href="#t_array">Array Type</a></li>
				49	<li><a href="#t_function">Function Type</a></li>
				50	<li><a href="#t_pointer">Pointer Type</a></li>
				51	<li><a href="#t_struct">Structure Type</a></li>
				52	<li><a href="#t_pstruct">Packed Structure Type</a></li>
				53	<li><a href="#t_vector">Vector Type</a></li>
				54	<li><a href="#t_opaque">Opaque Type</a></li>
				55	</ol>
				56	</li>
				57	</ol>
				58	</li>
				59	<li><a href="#constants">Constants</a>
				60	<ol>
				61	<li><a href="#simpleconstants">Simple Constants</a>
				62	<li><a href="#aggregateconstants">Aggregate Constants</a>
				63	<li><a href="#globalconstants">Global Variable and Function Addresses</a>
				64	<li><a href="#undefvalues">Undefined Values</a>
				65	<li><a href="#constantexprs">Constant Expressions</a>
				66	</ol>
				67	</li>
				68	<li><a href="#othervalues">Other Values</a>
				69	<ol>
				70	<li><a href="#inlineasm">Inline Assembler Expressions</a>
				71	</ol>
				72	</li>
				73	<li><a href="#instref">Instruction Reference</a>
				74	<ol>
				75	<li><a href="#terminators">Terminator Instructions</a>
				76	<ol>
				77	<li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
				78	<li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
				79	<li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
				80	<li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
				81	<li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
				82	<li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
				83	</ol>
				84	</li>
				85	<li><a href="#binaryops">Binary Operations</a>
				86	<ol>
				87	<li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
				88	<li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
				89	<li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
				90	<li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
				91	<li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
				92	<li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
				93	<li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
				94	<li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
				95	<li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
				96	</ol>
				97	</li>
				98	<li><a href="#bitwiseops">Bitwise Binary Operations</a>
				99	<ol>
				100	<li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
				101	<li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
				102	<li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
				103	<li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
				104	<li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
				105	<li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
				106	</ol>
				107	</li>
				108	<li><a href="#vectorops">Vector Operations</a>
				109	<ol>
				110	<li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
				111	<li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
				112	<li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
				113	</ol>
				114	</li>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	115	<li><a href="#aggregateops">Aggregate Operations</a>
				116	<ol>
				117	<li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
				118	<li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
				119	</ol>
				120	</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	121	<li><a href="#memoryops">Memory Access and Addressing Operations</a>
				122	<ol>
				123	<li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
				124	<li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
				125	<li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
				126	<li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
				127	<li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
				128	<li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
				129	</ol>
				130	</li>
				131	<li><a href="#convertops">Conversion Operations</a>
				132	<ol>
				133	<li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
				134	<li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
				135	<li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
				136	<li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
				137	<li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
				138	<li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
				139	<li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
				140	<li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
				141	<li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
				142	<li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
				143	<li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
				144	<li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
				145	</ol>
				146	<li><a href="#otherops">Other Operations</a>
				147	<ol>
				148	<li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
				149	<li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	150	<li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
				151	<li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	152	<li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
				153	<li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
				154	<li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
				155	<li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	156	<li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	157	</ol>
				158	</li>
				159	</ol>
				160	</li>
				161	<li><a href="#intrinsics">Intrinsic Functions</a>
				162	<ol>
				163	<li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
				164	<ol>
				165	<li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
				166	<li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
				167	<li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
				168	</ol>
				169	</li>
				170	<li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
				171	<ol>
				172	<li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
				173	<li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
				174	<li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
				175	</ol>
				176	</li>
				177	<li><a href="#int_codegen">Code Generator Intrinsics</a>
				178	<ol>
				179	<li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
				180	<li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
				181	<li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
				182	<li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
				183	<li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
				184	<li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
				185	<li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
				186	</ol>
				187	</li>
				188	<li><a href="#int_libc">Standard C Library Intrinsics</a>
				189	<ol>
				190	<li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
				191	<li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
				192	<li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
				193	<li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
				194	<li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	195	<li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
				196	<li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
				197	<li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	198	</ol>
				199	</li>
				200	<li><a href="#int_manip">Bit Manipulation Intrinsics</a>
				201	<ol>
				202	<li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
				203	<li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
				204	<li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
				205	<li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
				206	<li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
				207	<li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
				208	</ol>
				209	</li>
				210	<li><a href="#int_debugger">Debugger intrinsics</a></li>
				211	<li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	212	<li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	213	<ol>
				214	<li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	215	</ol>
				216	</li>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	217	<li><a href="#int_atomics">Atomic intrinsics</a>
				218	<ol>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	219	<li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	220	<li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	221	<li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	222	<li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
				223	<li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
				224	<li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
				225	<li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
				226	<li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
				227	<li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
				228	<li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
				229	<li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
				230	<li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
				231	<li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	232	</ol>
				233	</li>
Reid Spencer	b043f67	2007-07-20 19:59:11 +0000	[diff] [blame]	234	<li><a href="#int_general">General intrinsics</a>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	235	<ol>
Reid Spencer	b043f67	2007-07-20 19:59:11 +0000	[diff] [blame]	236	<li><a href="#int_var_annotation">
Tanya Lattner	51369f3	2007-09-22 00:01:26 +0000	[diff] [blame]	237	<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	238	<li><a href="#int_annotation">
Tanya Lattner	51369f3	2007-09-22 00:01:26 +0000	[diff] [blame]	239	<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	240	<li><a href="#int_trap">
				241	<tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	242	</ol>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	243	</li>
				244	</ol>
				245	</li>
				246	</ol>
				247
				248	<div class="doc_author">
				249	<p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
				250	and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
				251	</div>
				252
				253	<!-- *********************************************************************** -->
				254	<div class="doc_section"> <a name="abstract">Abstract </a></div>
				255	<!-- *********************************************************************** -->
				256
				257	<div class="doc_text">
				258	<p>This document is a reference manual for the LLVM assembly language.
Bill Wendling	e7846a5	2008-08-05 22:29:16 +0000	[diff] [blame]	259	LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	260	type safety, low-level operations, flexibility, and the capability of
				261	representing 'all' high-level languages cleanly. It is the common code
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	262	representation used throughout all phases of the LLVM compilation
				263	strategy.</p>
				264	</div>
				265
				266	<!-- *********************************************************************** -->
				267	<div class="doc_section"> <a name="introduction">Introduction</a> </div>
				268	<!-- *********************************************************************** -->
				269
				270	<div class="doc_text">
				271
				272	<p>The LLVM code representation is designed to be used in three
				273	different forms: as an in-memory compiler IR, as an on-disk bitcode
				274	representation (suitable for fast loading by a Just-In-Time compiler),
				275	and as a human readable assembly language representation. This allows
				276	LLVM to provide a powerful intermediate representation for efficient
				277	compiler transformations and analysis, while providing a natural means
				278	to debug and visualize the transformations. The three different forms
				279	of LLVM are all equivalent. This document describes the human readable
				280	representation and notation.</p>
				281
				282	<p>The LLVM representation aims to be light-weight and low-level
				283	while being expressive, typed, and extensible at the same time. It
				284	aims to be a "universal IR" of sorts, by being at a low enough level
				285	that high-level ideas may be cleanly mapped to it (similar to how
				286	microprocessors are "universal IR's", allowing many source languages to
				287	be mapped to them). By providing type information, LLVM can be used as
				288	the target of optimizations: for example, through pointer analysis, it
				289	can be proven that a C automatic variable is never accessed outside of
				290	the current function... allowing it to be promoted to a simple SSA
				291	value instead of a memory location.</p>
				292
				293	</div>
				294
				295	<!-- _______________________________________________________________________ -->
				296	<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
				297
				298	<div class="doc_text">
				299
				300	<p>It is important to note that this document describes 'well formed'
				301	LLVM assembly language. There is a difference between what the parser
				302	accepts and what is considered 'well formed'. For example, the
				303	following instruction is syntactically okay, but not well formed:</p>
				304
				305	<div class="doc_code">
				306	<pre>
				307	%x = <a href="#i_add">add</a> i32 1, %x
				308	</pre>
				309	</div>
				310
				311	<p>...because the definition of <tt>%x</tt> does not dominate all of
				312	its uses. The LLVM infrastructure provides a verification pass that may
				313	be used to verify that an LLVM module is well formed. This pass is
				314	automatically run by the parser after parsing input assembly and by
				315	the optimizer before it outputs bitcode. The violations pointed out
				316	by the verifier pass indicate bugs in transformation passes or input to
				317	the parser.</p>
				318	</div>
				319
Chris Lattner	a83fdc0	2007-10-03 17:34:29 +0000	[diff] [blame]	320	<!-- Describe the typesetting conventions here. -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	321
				322	<!-- *********************************************************************** -->
				323	<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
				324	<!-- *********************************************************************** -->
				325
				326	<div class="doc_text">
				327
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	328	<p>LLVM identifiers come in two basic types: global and local. Global
				329	identifiers (functions, global variables) begin with the @ character. Local
				330	identifiers (register names, types) begin with the % character. Additionally,
				331	there are three different formats for identifiers, for different purposes:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	332
				333	<ol>
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	334	<li>Named values are represented as a string of characters with their prefix.
				335	For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
				336	regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	337	Identifiers which require other characters in their names can be surrounded
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	338	with quotes. In this way, anything except a <tt>"</tt> character can
				339	be used in a named value.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	340
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	341	<li>Unnamed values are represented as an unsigned numeric value with their
				342	prefix. For example, %12, @2, %44.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	343
				344	<li>Constants, which are described in a <a href="#constants">section about
				345	constants</a>, below.</li>
				346	</ol>
				347
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	348	<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	349	don't need to worry about name clashes with reserved words, and the set of
				350	reserved words may be expanded in the future without penalty. Additionally,
				351	unnamed identifiers allow a compiler to quickly come up with a temporary
				352	variable without having to avoid symbol table conflicts.</p>
				353
				354	<p>Reserved words in LLVM are very similar to reserved words in other
				355	languages. There are keywords for different opcodes
				356	('<tt><a href="#i_add">add</a></tt>',
				357	'<tt><a href="#i_bitcast">bitcast</a></tt>',
				358	'<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
				359	href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
				360	and others. These reserved words cannot conflict with variable names, because
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	361	none of them start with a prefix character ('%' or '@').</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	362
				363	<p>Here is an example of LLVM code to multiply the integer variable
				364	'<tt>%X</tt>' by 8:</p>
				365
				366	<p>The easy way:</p>
				367
				368	<div class="doc_code">
				369	<pre>
				370	%result = <a href="#i_mul">mul</a> i32 %X, 8
				371	</pre>
				372	</div>
				373
				374	<p>After strength reduction:</p>
				375
				376	<div class="doc_code">
				377	<pre>
				378	%result = <a href="#i_shl">shl</a> i32 %X, i8 3
				379	</pre>
				380	</div>
				381
				382	<p>And the hard way:</p>
				383
				384	<div class="doc_code">
				385	<pre>
				386	<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
				387	<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
				388	%result = <a href="#i_add">add</a> i32 %1, %1
				389	</pre>
				390	</div>
				391
				392	<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
				393	important lexical features of LLVM:</p>
				394
				395	<ol>
				396
				397	<li>Comments are delimited with a '<tt>;</tt>' and go until the end of
				398	line.</li>
				399
				400	<li>Unnamed temporaries are created when the result of a computation is not
				401	assigned to a named value.</li>
				402
				403	<li>Unnamed temporaries are numbered sequentially</li>
				404
				405	</ol>
				406
				407	<p>...and it also shows a convention that we follow in this document. When
				408	demonstrating instructions, we will follow an instruction with a comment that
				409	defines the type and name of value produced. Comments are shown in italic
				410	text.</p>
				411
				412	</div>
				413
				414	<!-- *********************************************************************** -->
				415	<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
				416	<!-- *********************************************************************** -->
				417
				418	<!-- ======================================================================= -->
				419	<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
				420	</div>
				421
				422	<div class="doc_text">
				423
				424	<p>LLVM programs are composed of "Module"s, each of which is a
				425	translation unit of the input programs. Each module consists of
				426	functions, global variables, and symbol table entries. Modules may be
				427	combined together with the LLVM linker, which merges function (and
				428	global variable) definitions, resolves forward declarations, and merges
				429	symbol table entries. Here is an example of the "hello world" module:</p>
				430
				431	<div class="doc_code">
				432	<pre><i>; Declare the string constant as a global constant...</i>
				433	<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
				434	href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
				435
				436	<i>; External declaration of the puts function</i>
				437	<a href="#functionstructure">declare</a> i32 @puts(i8 ) <i>; i32(i8 )* </i>
				438
				439	<i>; Definition of main function</i>
				440	define i32 @main() { <i>; i32()* </i>
				441	<i>; Convert [13x i8 ]* to i8 *...</i>
				442	%cast210 = <a
				443	href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
				444
				445	<i>; Call puts function to write out the string to stdout...</i>
				446	<a
				447	href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
				448	<a
				449	href="#i_ret">ret</a> i32 0<br>}<br>
				450	</pre>
				451	</div>
				452
				453	<p>This example is made up of a <a href="#globalvars">global variable</a>
				454	named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
				455	function, and a <a href="#functionstructure">function definition</a>
				456	for "<tt>main</tt>".</p>
				457
				458	<p>In general, a module is made up of a list of global values,
				459	where both functions and global variables are global values. Global values are
				460	represented by a pointer to a memory location (in this case, a pointer to an
				461	array of char, and a pointer to a function), and have one of the following <a
				462	href="#linkage">linkage types</a>.</p>
				463
				464	</div>
				465
				466	<!-- ======================================================================= -->
				467	<div class="doc_subsection">
				468	<a name="linkage">Linkage Types</a>
				469	</div>
				470
				471	<div class="doc_text">
				472
				473	<p>
				474	All Global Variables and Functions have one of the following types of linkage:
				475	</p>
				476
				477	<dl>
				478
Dale Johannesen	96e7e09	2008-05-23 23:13:41 +0000	[diff] [blame]	479	<dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	480
				481	<dd>Global values with internal linkage are only directly accessible by
				482	objects in the current module. In particular, linking code into a module with
				483	an internal global value may cause the internal to be renamed as necessary to
				484	avoid collisions. Because the symbol is internal to the module, all
				485	references can be updated. This corresponds to the notion of the
				486	'<tt>static</tt>' keyword in C.
				487	</dd>
				488
				489	<dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
				490
				491	<dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
				492	the same name when linkage occurs. This is typically used to implement
				493	inline functions, templates, or other code which must be generated in each
				494	translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
				495	allowed to be discarded.
				496	</dd>
				497
Dale Johannesen	96e7e09	2008-05-23 23:13:41 +0000	[diff] [blame]	498	<dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
				499
				500	<dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
				501	linkage, except that unreferenced <tt>common</tt> globals may not be
				502	discarded. This is used for globals that may be emitted in multiple
				503	translation units, but that are not guaranteed to be emitted into every
				504	translation unit that uses them. One example of this is tentative
				505	definitions in C, such as "<tt>int X;</tt>" at global scope.
				506	</dd>
				507
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	508	<dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
				509
Dale Johannesen	96e7e09	2008-05-23 23:13:41 +0000	[diff] [blame]	510	<dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
				511	that some targets may choose to emit different assembly sequences for them
				512	for target-dependent reasons. This is used for globals that are declared
				513	"weak" in C source code.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	514	</dd>
				515
				516	<dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
				517
				518	<dd>"<tt>appending</tt>" linkage may only be applied to global variables of
				519	pointer to array type. When two global variables with appending linkage are
				520	linked together, the two global arrays are appended together. This is the
				521	LLVM, typesafe, equivalent of having the system linker append together
				522	"sections" with identical names when .o files are linked.
				523	</dd>
				524
				525	<dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	526	<dd>The semantics of this linkage follow the ELF object file model: the
				527	symbol is weak until linked, if not linked, the symbol becomes null instead
				528	of being an undefined reference.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	529	</dd>
				530
				531	<dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
				532
				533	<dd>If none of the above identifiers are used, the global is externally
				534	visible, meaning that it participates in linkage and can be used to resolve
				535	external symbol references.
				536	</dd>
				537	</dl>
				538
				539	<p>
				540	The next two types of linkage are targeted for Microsoft Windows platform
				541	only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	542	DLLs (Dynamic Link Libraries).
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	543	</p>
				544
				545	<dl>
				546	<dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
				547
				548	<dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
				549	or variable via a global pointer to a pointer that is set up by the DLL
				550	exporting the symbol. On Microsoft Windows targets, the pointer name is
				551	formed by combining <code>_imp__</code> and the function or variable name.
				552	</dd>
				553
				554	<dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
				555
				556	<dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
				557	pointer to a pointer in a DLL, so that it can be referenced with the
				558	<tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
				559	name is formed by combining <code>_imp__</code> and the function or variable
				560	name.
				561	</dd>
				562
				563	</dl>
				564
				565	<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
				566	variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
				567	variable and was linked with this one, one of the two would be renamed,
				568	preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
				569	external (i.e., lacking any linkage declarations), they are accessible
				570	outside of the current module.</p>
				571	<p>It is illegal for a function <i>declaration</i>
				572	to have any linkage type other than "externally visible", <tt>dllimport</tt>,
				573	or <tt>extern_weak</tt>.</p>
				574	<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
				575	linkages.
				576	</div>
				577
				578	<!-- ======================================================================= -->
				579	<div class="doc_subsection">
				580	<a name="callingconv">Calling Conventions</a>
				581	</div>
				582
				583	<div class="doc_text">
				584
				585	<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
				586	and <a href="#i_invoke">invokes</a> can all have an optional calling convention
				587	specified for the call. The calling convention of any pair of dynamic
				588	caller/callee must match, or the behavior of the program is undefined. The
				589	following calling conventions are supported by LLVM, and more may be added in
				590	the future:</p>
				591
				592	<dl>
				593	<dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
				594
				595	<dd>This calling convention (the default if no other calling convention is
				596	specified) matches the target C calling conventions. This calling convention
				597	supports varargs function calls and tolerates some mismatch in the declared
				598	prototype and implemented declaration of the function (as does normal C).
				599	</dd>
				600
				601	<dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
				602
				603	<dd>This calling convention attempts to make calls as fast as possible
				604	(e.g. by passing things in registers). This calling convention allows the
				605	target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	606	without having to conform to an externally specified ABI (Application Binary
				607	Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer	0744492	2008-05-14 09:17:12 +0000	[diff] [blame]	608	<a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
				609	supported. This calling convention does not support varargs and requires the
				610	prototype of all callees to exactly match the prototype of the function
				611	definition.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	612	</dd>
				613
				614	<dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
				615
				616	<dd>This calling convention attempts to make code in the caller as efficient
				617	as possible under the assumption that the call is not commonly executed. As
				618	such, these calls often preserve all registers so that the call does not break
				619	any live ranges in the caller side. This calling convention does not support
				620	varargs and requires the prototype of all callees to exactly match the
				621	prototype of the function definition.
				622	</dd>
				623
				624	<dt><b>"<tt>cc <<em>n</em>></tt>" - Numbered convention</b>:</dt>
				625
				626	<dd>Any calling convention may be specified by number, allowing
				627	target-specific calling conventions to be used. Target specific calling
				628	conventions start at 64.
				629	</dd>
				630	</dl>
				631
				632	<p>More calling conventions can be added/defined on an as-needed basis, to
				633	support pascal conventions or any other well-known target-independent
				634	convention.</p>
				635
				636	</div>
				637
				638	<!-- ======================================================================= -->
				639	<div class="doc_subsection">
				640	<a name="visibility">Visibility Styles</a>
				641	</div>
				642
				643	<div class="doc_text">
				644
				645	<p>
				646	All Global Variables and Functions have one of the following visibility styles:
				647	</p>
				648
				649	<dl>
				650	<dt><b>"<tt>default</tt>" - Default style</b>:</dt>
				651
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	652	<dd>On targets that use the ELF object file format, default visibility means
				653	that the declaration is visible to other
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	654	modules and, in shared libraries, means that the declared entity may be
				655	overridden. On Darwin, default visibility means that the declaration is
				656	visible to other modules. Default visibility corresponds to "external
				657	linkage" in the language.
				658	</dd>
				659
				660	<dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
				661
				662	<dd>Two declarations of an object with hidden visibility refer to the same
				663	object if they are in the same shared object. Usually, hidden visibility
				664	indicates that the symbol will not be placed into the dynamic symbol table,
				665	so no other module (executable or shared library) can reference it
				666	directly.
				667	</dd>
				668
				669	<dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
				670
				671	<dd>On ELF, protected visibility indicates that the symbol will be placed in
				672	the dynamic symbol table, but that references within the defining module will
				673	bind to the local symbol. That is, the symbol cannot be overridden by another
				674	module.
				675	</dd>
				676	</dl>
				677
				678	</div>
				679
				680	<!-- ======================================================================= -->
				681	<div class="doc_subsection">
				682	<a name="globalvars">Global Variables</a>
				683	</div>
				684
				685	<div class="doc_text">
				686
				687	<p>Global variables define regions of memory allocated at compilation time
				688	instead of run-time. Global variables may optionally be initialized, may have
				689	an explicit section to be placed in, and may have an optional explicit alignment
				690	specified. A variable may be defined as "thread_local", which means that it
				691	will not be shared by threads (each thread will have a separated copy of the
				692	variable). A variable may be defined as a global "constant," which indicates
				693	that the contents of the variable will <b>never</b> be modified (enabling better
				694	optimization, allowing the global data to be placed in the read-only section of
				695	an executable, etc). Note that variables that need runtime initialization
				696	cannot be marked "constant" as there is a store to the variable.</p>
				697
				698	<p>
				699	LLVM explicitly allows <em>declarations</em> of global variables to be marked
				700	constant, even if the final definition of the global is not. This capability
				701	can be used to enable slightly better optimization of the program, but requires
				702	the language definition to guarantee that optimizations based on the
				703	'constantness' are valid for the translation units that do not include the
				704	definition.
				705	</p>
				706
				707	<p>As SSA values, global variables define pointer values that are in
				708	scope (i.e. they dominate) all basic blocks in the program. Global
				709	variables always define a pointer to their "content" type because they
				710	describe a region of memory, and all memory objects in LLVM are
				711	accessed through pointers.</p>
				712
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	713	<p>A global variable may be declared to reside in a target-specifc numbered
				714	address space. For targets that support them, address spaces may affect how
				715	optimizations are performed and/or what target instructions are used to access
Christopher Lamb	20a39e9	2007-12-12 08:44:39 +0000	[diff] [blame]	716	the variable. The default address space is zero. The address space qualifier
				717	must precede any other attributes.</p>
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	718
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	719	<p>LLVM allows an explicit section to be specified for globals. If the target
				720	supports it, it will emit globals to the section specified.</p>
				721
				722	<p>An explicit alignment may be specified for a global. If not present, or if
				723	the alignment is set to zero, the alignment of the global is set by the target
				724	to whatever it feels convenient. If an explicit alignment is specified, the
				725	global is forced to have at least that much alignment. All alignments must be
				726	a power of 2.</p>
				727
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	728	<p>For example, the following defines a global in a numbered address space with
				729	an initializer, section, and alignment:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	730
				731	<div class="doc_code">
				732	<pre>
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	733	@G = constant float 1.0 addrspace(5), section "foo", align 4
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	734	</pre>
				735	</div>
				736
				737	</div>
				738
				739
				740	<!-- ======================================================================= -->
				741	<div class="doc_subsection">
				742	<a name="functionstructure">Functions</a>
				743	</div>
				744
				745	<div class="doc_text">
				746
				747	<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
				748	an optional <a href="#linkage">linkage type</a>, an optional
				749	<a href="#visibility">visibility style</a>, an optional
				750	<a href="#callingconv">calling convention</a>, a return type, an optional
				751	<a href="#paramattrs">parameter attribute</a> for the return type, a function
				752	name, a (possibly empty) argument list (each with optional
				753	<a href="#paramattrs">parameter attributes</a>), an optional section, an
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	754	optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattner	ee20254	2008-10-04 18:10:21 +0000	[diff] [blame]	755	an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	756
				757	LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
				758	optional <a href="#linkage">linkage type</a>, an optional
				759	<a href="#visibility">visibility style</a>, an optional
				760	<a href="#callingconv">calling convention</a>, a return type, an optional
				761	<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	762	name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksen	d606f5b	2007-12-10 03:30:21 +0000	[diff] [blame]	763	<a href="#gc">garbage collector name</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	764
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	765	<p>A function definition contains a list of basic blocks, forming the CFG
				766	(Control Flow Graph) for
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	767	the function. Each basic block may optionally start with a label (giving the
				768	basic block a symbol table entry), contains a list of instructions, and ends
				769	with a <a href="#terminators">terminator</a> instruction (such as a branch or
				770	function return).</p>
				771
				772	<p>The first basic block in a function is special in two ways: it is immediately
				773	executed on entrance to the function, and it is not allowed to have predecessor
				774	basic blocks (i.e. there can not be any branches to the entry block of a
				775	function). Because the block can have no predecessors, it also cannot have any
				776	<a href="#i_phi">PHI nodes</a>.</p>
				777
				778	<p>LLVM allows an explicit section to be specified for functions. If the target
				779	supports it, it will emit functions to the section specified.</p>
				780
				781	<p>An explicit alignment may be specified for a function. If not present, or if
				782	the alignment is set to zero, the alignment of the function is set by the target
				783	to whatever it feels convenient. If an explicit alignment is specified, the
				784	function is forced to have at least that much alignment. All alignments must be
				785	a power of 2.</p>
				786
				787	</div>
				788
				789
				790	<!-- ======================================================================= -->
				791	<div class="doc_subsection">
				792	<a name="aliasstructure">Aliases</a>
				793	</div>
				794	<div class="doc_text">
				795	<p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov	9682281	2008-03-22 08:36:14 +0000	[diff] [blame]	796	function, global variable, another alias or bitcast of global value). Aliases
				797	may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	798	optional <a href="#visibility">visibility style</a>.</p>
				799
				800	<h5>Syntax:</h5>
				801
				802	<div class="doc_code">
				803	<pre>
Duncan Sands	d7bfabf	2008-09-12 20:48:21 +0000	[diff] [blame]	804	@<Name> = alias [Linkage] [Visibility] <AliaseeTy> @<Aliasee>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	805	</pre>
				806	</div>
				807
				808	</div>
				809
				810
				811
				812	<!-- ======================================================================= -->
				813	<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
				814	<div class="doc_text">
				815	<p>The return type and each parameter of a function type may have a set of
				816	<i>parameter attributes</i> associated with them. Parameter attributes are
				817	used to communicate additional information about the result or parameters of
Duncan Sands	f5588dc	2007-11-27 13:23:08 +0000	[diff] [blame]	818	a function. Parameter attributes are considered to be part of the function,
				819	not of the function type, so functions with different parameter attributes
				820	can have the same function type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	821
				822	<p>Parameter attributes are simple keywords that follow the type specified. If
				823	multiple parameter attributes are needed, they are space separated. For
				824	example:</p>
				825
				826	<div class="doc_code">
				827	<pre>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	828	declare i32 @printf(i8* noalias , ...)
				829	declare i32 @atoi(i8 zeroext*)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	830	</pre>
				831	</div>
				832
Duncan Sands	f5588dc	2007-11-27 13:23:08 +0000	[diff] [blame]	833	<p>Note that any attributes for the function result (<tt>nounwind</tt>,
				834	<tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	835
				836	<p>Currently, only the following parameter attributes are defined:</p>
				837	<dl>
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	838	<dt><tt>zeroext</tt></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	839	<dd>This indicates that the parameter should be zero extended just before
				840	a call to this function.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	841
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	842	<dt><tt>signext</tt></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	843	<dd>This indicates that the parameter should be sign extended just before
				844	a call to this function.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	845
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	846	<dt><tt>inreg</tt></dt>
Dale Johannesen	c08a0e2	2008-09-25 20:47:45 +0000	[diff] [blame]	847	<dd>This indicates that this parameter or return value should be treated
				848	in a special target-dependent fashion during while emitting code for a
				849	function call or return (usually, by putting it in a register as opposed
				850	to memory; in some places it is used to distinguish between two different
				851	kinds of registers). Use of this attribute is target-specific</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	852
				853	<dt><tt>byval</tt></dt>
Chris Lattner	04c8618	2008-01-15 04:34:22 +0000	[diff] [blame]	854	<dd>This indicates that the pointer parameter should really be passed by
				855	value to the function. The attribute implies that a hidden copy of the
				856	pointee is made between the caller and the callee, so the callee is unable
Chris Lattner	6a9f3c4	2008-08-05 18:21:08 +0000	[diff] [blame]	857	to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner	04c8618	2008-01-15 04:34:22 +0000	[diff] [blame]	858	pointer arguments. It is generally used to pass structs and arrays by
				859	value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	860
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	861	<dt><tt>sret</tt></dt>
Duncan Sands	616cc03	2008-02-18 04:19:38 +0000	[diff] [blame]	862	<dd>This indicates that the pointer parameter specifies the address of a
				863	structure that is the return value of the function in the source program.
Duncan Sands	ef0e9e4	2008-03-17 12:17:41 +0000	[diff] [blame]	864	Loads and stores to the structure are assumed not to trap.
Duncan Sands	616cc03	2008-02-18 04:19:38 +0000	[diff] [blame]	865	May only be applied to the first parameter.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	866
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	867	<dt><tt>noalias</tt></dt>
Owen Anderson	c4fc4cd	2008-02-18 04:09:01 +0000	[diff] [blame]	868	<dd>This indicates that the parameter does not alias any global or any other
				869	parameter. The caller is responsible for ensuring that this is the case,
				870	usually by placing the value in a stack allocation.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	871
Duncan Sands	4ee4681	2007-07-27 19:57:41 +0000	[diff] [blame]	872	<dt><tt>nest</tt></dt>
Duncan Sands	f1a7d4c	2008-07-08 09:27:25 +0000	[diff] [blame]	873	<dd>This indicates that the pointer parameter can be excised using the
Duncan Sands	4ee4681	2007-07-27 19:57:41 +0000	[diff] [blame]	874	<a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	875	</dl>
				876
				877	</div>
				878
				879	<!-- ======================================================================= -->
				880	<div class="doc_subsection">
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	881	<a name="gc">Garbage Collector Names</a>
				882	</div>
				883
				884	<div class="doc_text">
				885	<p>Each function may specify a garbage collector name, which is simply a
				886	string.</p>
				887
				888	<div class="doc_code"><pre
				889	>define void @f() gc "name" { ...</pre></div>
				890
				891	<p>The compiler declares the supported values of <i>name</i>. Specifying a
				892	collector which will cause the compiler to alter its output in order to support
				893	the named garbage collection algorithm.</p>
				894	</div>
				895
				896	<!-- ======================================================================= -->
				897	<div class="doc_subsection">
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	898	<a name="fnattrs">Function Attributes</a>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	899	</div>
				900
				901	<div class="doc_text">
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	902
				903	<p>Function attributes are set to communicate additional information about
				904	a function. Function attributes are considered to be part of the function,
				905	not of the function type, so functions with different parameter attributes
				906	can have the same function type.</p>
				907
				908	<p>Function attributes are simple keywords that follow the type specified. If
				909	multiple attributes are needed, they are space separated. For
				910	example:</p>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	911
				912	<div class="doc_code">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	913	<pre>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	914	define void @f() noinline { ... }
				915	define void @f() alwaysinline { ... }
				916	define void @f() alwaysinline optsize { ... }
				917	define void @f() optsize
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	918	</pre>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	919	</div>
				920
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	921	<dl>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	922	<dt><tt>alwaysinline</tt></dt>
Chris Lattner	82d70f9	2008-10-04 18:23:17 +0000	[diff] [blame^]	923	<dd>This attribute indicates that the inliner should attempt to inline this
				924	function into callers whenever possible, ignoring any active inlining size
				925	threshold for this caller.</dd>
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	926
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	927	<dt><tt>noinline</tt></dt>
Chris Lattner	82d70f9	2008-10-04 18:23:17 +0000	[diff] [blame^]	928	<dd>This attribute indicates that the inliner should never inline this function
				929	in any situation. This attribute may not be used together with
				930	<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	931
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	932	<dt><tt>optsize</tt></dt>
Devang Patel	c29099b	2008-09-29 18:34:44 +0000	[diff] [blame]	933	<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner	82d70f9	2008-10-04 18:23:17 +0000	[diff] [blame^]	934	make choices that keep the code size of this function low, and otherwise do
				935	optimizations specifically to reduce code size.</dd>
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	936
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	937	<dt><tt>noreturn</tt></dt>
Chris Lattner	82d70f9	2008-10-04 18:23:17 +0000	[diff] [blame^]	938	<dd>This function attribute indicates that the function never returns normally.
				939	This produces undefined behavior at runtime if the function ever does
				940	dynamically return.</dd>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	941
				942	<dt><tt>nounwind</tt></dt>
Chris Lattner	82d70f9	2008-10-04 18:23:17 +0000	[diff] [blame^]	943	<dd>This function attribute indicates that the function never returns with an
				944	unwind or exceptional control flow. If the function does unwind, its runtime
				945	behavior is undefined.</dd>
				946
				947	<dt><tt>readnone</tt></dt>
				948	<dd>This attribute indicates that the function computes its result (or its
				949	thrown exception) based strictly on its arguments. It does not read any global
				950	mutable state (e.g. memory, control registers, etc) visible to caller functions.
				951	Furthermore, <tt>readnone</tt> functions never change any state visible to their
				952	caller.
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	953
				954	<dt><tt>readonly</tt></dt>
Chris Lattner	82d70f9	2008-10-04 18:23:17 +0000	[diff] [blame^]	955	<dd>This function attribute indicates that the function has no side-effects on
				956	the calling function, but that it depends on state (memory state, control
				957	register state, etc) that may be set in the caller. A readonly function always
				958	returns the same value (or throws the same exception) whenever it is called with
				959	a particular set of arguments and global state.</dd>
				960
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	961	</dl>
				962
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	963	</div>
				964
				965	<!-- ======================================================================= -->
				966	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	967	<a name="moduleasm">Module-Level Inline Assembly</a>
				968	</div>
				969
				970	<div class="doc_text">
				971	<p>
				972	Modules may contain "module-level inline asm" blocks, which corresponds to the
				973	GCC "file scope inline asm" blocks. These blocks are internally concatenated by
				974	LLVM and treated as a single unit, but may be separated in the .ll file if
				975	desired. The syntax is very simple:
				976	</p>
				977
				978	<div class="doc_code">
				979	<pre>
				980	module asm "inline asm code goes here"
				981	module asm "more can go here"
				982	</pre>
				983	</div>
				984
				985	<p>The strings can contain any character by escaping non-printable characters.
				986	The escape sequence used is simply "\xx" where "xx" is the two digit hex code
				987	for the number.
				988	</p>
				989
				990	<p>
				991	The inline asm code is simply printed to the machine code .s file when
				992	assembly code is generated.
				993	</p>
				994	</div>
				995
				996	<!-- ======================================================================= -->
				997	<div class="doc_subsection">
				998	<a name="datalayout">Data Layout</a>
				999	</div>
				1000
				1001	<div class="doc_text">
				1002	<p>A module may specify a target specific data layout string that specifies how
				1003	data is to be laid out in memory. The syntax for the data layout is simply:</p>
				1004	<pre> target datalayout = "<i>layout specification</i>"</pre>
				1005	<p>The <i>layout specification</i> consists of a list of specifications
				1006	separated by the minus sign character ('-'). Each specification starts with a
				1007	letter and may include other information after the letter to define some
				1008	aspect of the data layout. The specifications accepted are as follows: </p>
				1009	<dl>
				1010	<dt><tt>E</tt></dt>
				1011	<dd>Specifies that the target lays out data in big-endian form. That is, the
				1012	bits with the most significance have the lowest address location.</dd>
				1013	<dt><tt>e</tt></dt>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1014	<dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1015	the bits with the least significance have the lowest address location.</dd>
				1016	<dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1017	<dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
				1018	<i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
				1019	alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
				1020	too.</dd>
				1021	<dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1022	<dd>This specifies the alignment for an integer type of a given bit
				1023	<i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
				1024	<dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1025	<dd>This specifies the alignment for a vector type of a given bit
				1026	<i>size</i>.</dd>
				1027	<dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1028	<dd>This specifies the alignment for a floating point type of a given bit
				1029	<i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
				1030	(double).</dd>
				1031	<dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1032	<dd>This specifies the alignment for an aggregate type of a given bit
				1033	<i>size</i>.</dd>
				1034	</dl>
				1035	<p>When constructing the data layout for a given target, LLVM starts with a
				1036	default set of specifications which are then (possibly) overriden by the
				1037	specifications in the <tt>datalayout</tt> keyword. The default specifications
				1038	are given in this list:</p>
				1039	<ul>
				1040	<li><tt>E</tt> - big endian</li>
				1041	<li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
				1042	<li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
				1043	<li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
				1044	<li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
				1045	<li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1046	<li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1047	alignment of 64-bits</li>
				1048	<li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
				1049	<li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
				1050	<li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
				1051	<li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
				1052	<li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
				1053	</ul>
Chris Lattner	6a9f3c4	2008-08-05 18:21:08 +0000	[diff] [blame]	1054	<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1055	following rules:
				1056	<ol>
				1057	<li>If the type sought is an exact match for one of the specifications, that
				1058	specification is used.</li>
				1059	<li>If no match is found, and the type sought is an integer type, then the
				1060	smallest integer type that is larger than the bitwidth of the sought type is
				1061	used. If none of the specifications are larger than the bitwidth then the the
				1062	largest integer type is used. For example, given the default specifications
				1063	above, the i7 type will use the alignment of i8 (next largest) while both
				1064	i65 and i256 will use the alignment of i64 (largest specified).</li>
				1065	<li>If no match is found, and the type sought is a vector type, then the
				1066	largest vector type that is smaller than the sought vector type will be used
				1067	as a fall back. This happens because <128 x double> can be implemented in
				1068	terms of 64 <2 x double>, for example.</li>
				1069	</ol>
				1070	</div>
				1071
				1072	<!-- *********************************************************************** -->
				1073	<div class="doc_section"> <a name="typesystem">Type System</a> </div>
				1074	<!-- *********************************************************************** -->
				1075
				1076	<div class="doc_text">
				1077
				1078	<p>The LLVM type system is one of the most important features of the
				1079	intermediate representation. Being typed enables a number of
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1080	optimizations to be performed on the intermediate representation directly,
				1081	without having to do
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1082	extra analyses on the side before the transformation. A strong type
				1083	system makes it easier to read the generated code and enables novel
				1084	analyses and transformations that are not feasible to perform on normal
				1085	three address code representations.</p>
				1086
				1087	</div>
				1088
				1089	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1090	<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1091	Classifications</a> </div>
				1092	<div class="doc_text">
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1093	<p>The types fall into a few useful
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1094	classifications:</p>
				1095
				1096	<table border="1" cellspacing="0" cellpadding="4">
				1097	<tbody>
				1098	<tr><th>Classification</th><th>Types</th></tr>
				1099	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1100	<td><a href="#t_integer">integer</a></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1101	<td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
				1102	</tr>
				1103	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1104	<td><a href="#t_floating">floating point</a></td>
				1105	<td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1106	</tr>
				1107	<tr>
				1108	<td><a name="t_firstclass">first class</a></td>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1109	<td><a href="#t_integer">integer</a>,
				1110	<a href="#t_floating">floating point</a>,
				1111	<a href="#t_pointer">pointer</a>,
Dan Gohman	f6237db	2008-06-18 18:42:13 +0000	[diff] [blame]	1112	<a href="#t_vector">vector</a>,
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	1113	<a href="#t_struct">structure</a>,
				1114	<a href="#t_array">array</a>,
Dan Gohman	d13951e	2008-05-23 22:50:26 +0000	[diff] [blame]	1115	<a href="#t_label">label</a>.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1116	</td>
				1117	</tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1118	<tr>
				1119	<td><a href="#t_primitive">primitive</a></td>
				1120	<td><a href="#t_label">label</a>,
				1121	<a href="#t_void">void</a>,
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1122	<a href="#t_floating">floating point</a>.</td>
				1123	</tr>
				1124	<tr>
				1125	<td><a href="#t_derived">derived</a></td>
				1126	<td><a href="#t_integer">integer</a>,
				1127	<a href="#t_array">array</a>,
				1128	<a href="#t_function">function</a>,
				1129	<a href="#t_pointer">pointer</a>,
				1130	<a href="#t_struct">structure</a>,
				1131	<a href="#t_pstruct">packed structure</a>,
				1132	<a href="#t_vector">vector</a>,
				1133	<a href="#t_opaque">opaque</a>.
				1134	</tr>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1135	</tbody>
				1136	</table>
				1137
				1138	<p>The <a href="#t_firstclass">first class</a> types are perhaps the
				1139	most important. Values of these types are the only ones which can be
				1140	produced by instructions, passed as arguments, or used as operands to
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	1141	instructions.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1142	</div>
				1143
				1144	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1145	<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1146
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1147	<div class="doc_text">
				1148	<p>The primitive types are the fundamental building blocks of the LLVM
				1149	system.</p>
				1150
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1151	</div>
				1152
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1153	<!-- _______________________________________________________________________ -->
				1154	<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
				1155
				1156	<div class="doc_text">
				1157	<table>
				1158	<tbody>
				1159	<tr><th>Type</th><th>Description</th></tr>
				1160	<tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
				1161	<tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
				1162	<tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
				1163	<tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
				1164	<tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
				1165	</tbody>
				1166	</table>
				1167	</div>
				1168
				1169	<!-- _______________________________________________________________________ -->
				1170	<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
				1171
				1172	<div class="doc_text">
				1173	<h5>Overview:</h5>
				1174	<p>The void type does not represent any value and has no size.</p>
				1175
				1176	<h5>Syntax:</h5>
				1177
				1178	<pre>
				1179	void
				1180	</pre>
				1181	</div>
				1182
				1183	<!-- _______________________________________________________________________ -->
				1184	<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
				1185
				1186	<div class="doc_text">
				1187	<h5>Overview:</h5>
				1188	<p>The label type represents code labels.</p>
				1189
				1190	<h5>Syntax:</h5>
				1191
				1192	<pre>
				1193	label
				1194	</pre>
				1195	</div>
				1196
				1197
				1198	<!-- ======================================================================= -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1199	<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
				1200
				1201	<div class="doc_text">
				1202
				1203	<p>The real power in LLVM comes from the derived types in the system.
				1204	This is what allows a programmer to represent arrays, functions,
				1205	pointers, and other useful types. Note that these derived types may be
				1206	recursive: For example, it is possible to have a two dimensional array.</p>
				1207
				1208	</div>
				1209
				1210	<!-- _______________________________________________________________________ -->
				1211	<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
				1212
				1213	<div class="doc_text">
				1214
				1215	<h5>Overview:</h5>
				1216	<p>The integer type is a very simple derived type that simply specifies an
				1217	arbitrary bit width for the integer type desired. Any bit width from 1 bit to
				1218	2^23-1 (about 8 million) can be specified.</p>
				1219
				1220	<h5>Syntax:</h5>
				1221
				1222	<pre>
				1223	iN
				1224	</pre>
				1225
				1226	<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
				1227	value.</p>
				1228
				1229	<h5>Examples:</h5>
				1230	<table class="layout">
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	1231	<tbody>
				1232	<tr>
				1233	<td><tt>i1</tt></td>
				1234	<td>a single-bit integer.</td>
				1235	</tr><tr>
				1236	<td><tt>i32</tt></td>
				1237	<td>a 32-bit integer.</td>
				1238	</tr><tr>
				1239	<td><tt>i1942652</tt></td>
				1240	<td>a really big integer of over 1 million bits.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1241	</tr>
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	1242	</tbody>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1243	</table>
				1244	</div>
				1245
				1246	<!-- _______________________________________________________________________ -->
				1247	<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
				1248
				1249	<div class="doc_text">
				1250
				1251	<h5>Overview:</h5>
				1252
				1253	<p>The array type is a very simple derived type that arranges elements
				1254	sequentially in memory. The array type requires a size (number of
				1255	elements) and an underlying data type.</p>
				1256
				1257	<h5>Syntax:</h5>
				1258
				1259	<pre>
				1260	[<# elements> x <elementtype>]
				1261	</pre>
				1262
				1263	<p>The number of elements is a constant integer value; elementtype may
				1264	be any type with a size.</p>
				1265
				1266	<h5>Examples:</h5>
				1267	<table class="layout">
				1268	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1269	<td class="left"><tt>[40 x i32]</tt></td>
				1270	<td class="left">Array of 40 32-bit integer values.</td>
				1271	</tr>
				1272	<tr class="layout">
				1273	<td class="left"><tt>[41 x i32]</tt></td>
				1274	<td class="left">Array of 41 32-bit integer values.</td>
				1275	</tr>
				1276	<tr class="layout">
				1277	<td class="left"><tt>[4 x i8]</tt></td>
				1278	<td class="left">Array of 4 8-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1279	</tr>
				1280	</table>
				1281	<p>Here are some examples of multidimensional arrays:</p>
				1282	<table class="layout">
				1283	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1284	<td class="left"><tt>[3 x [4 x i32]]</tt></td>
				1285	<td class="left">3x4 array of 32-bit integer values.</td>
				1286	</tr>
				1287	<tr class="layout">
				1288	<td class="left"><tt>[12 x [10 x float]]</tt></td>
				1289	<td class="left">12x10 array of single precision floating point values.</td>
				1290	</tr>
				1291	<tr class="layout">
				1292	<td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
				1293	<td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1294	</tr>
				1295	</table>
				1296
				1297	<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
				1298	length array. Normally, accesses past the end of an array are undefined in
				1299	LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
				1300	As a special case, however, zero length arrays are recognized to be variable
				1301	length. This allows implementation of 'pascal style arrays' with the LLVM
				1302	type "{ i32, [0 x float]}", for example.</p>
				1303
				1304	</div>
				1305
				1306	<!-- _______________________________________________________________________ -->
				1307	<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
				1308	<div class="doc_text">
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1309
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1310	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1311
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1312	<p>The function type can be thought of as a function signature. It
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1313	consists of a return type and a list of formal parameter types. The
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1314	return type of a function type is a scalar type, a void type, or a struct type.
Devang Patel	d5404c0	2008-03-24 20:52:42 +0000	[diff] [blame]	1315	If the return type is a struct type then all struct elements must be of first
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1316	class types, and the struct must have at least one element.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1317
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1318	<h5>Syntax:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1319
				1320	<pre>
				1321	<returntype list> (<parameter list>)
				1322	</pre>
				1323
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1324	<p>...where '<tt><parameter list></tt>' is a comma-separated list of type
				1325	specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
				1326	which indicates that the function takes a variable number of arguments.
				1327	Variable argument functions can access their arguments with the <a
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1328	href="#int_varargs">variable argument handling intrinsic</a> functions.
				1329	'<tt><returntype list></tt>' is a comma-separated list of
				1330	<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1331
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1332	<h5>Examples:</h5>
				1333	<table class="layout">
				1334	<tr class="layout">
				1335	<td class="left"><tt>i32 (i32)</tt></td>
				1336	<td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
				1337	</td>
				1338	</tr><tr class="layout">
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	1339	<td class="left"><tt>float (i16 signext, i32 )
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1340	</tt></td>
				1341	<td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
				1342	an <tt>i16</tt> that should be sign extended and a
				1343	<a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
				1344	<tt>float</tt>.
				1345	</td>
				1346	</tr><tr class="layout">
				1347	<td class="left"><tt>i32 (i8*, ...)</tt></td>
				1348	<td class="left">A vararg function that takes at least one
				1349	<a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
				1350	which returns an integer. This is the signature for <tt>printf</tt> in
				1351	LLVM.
				1352	</td>
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1353	</tr><tr class="layout">
				1354	<td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel	6dddba2	2008-03-24 18:10:52 +0000	[diff] [blame]	1355	<td class="left">A function taking an <tt>i32></tt>, returning two
				1356	<tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1357	</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1358	</tr>
				1359	</table>
				1360
				1361	</div>
				1362	<!-- _______________________________________________________________________ -->
				1363	<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
				1364	<div class="doc_text">
				1365	<h5>Overview:</h5>
				1366	<p>The structure type is used to represent a collection of data members
				1367	together in memory. The packing of the field types is defined to match
				1368	the ABI of the underlying processor. The elements of a structure may
				1369	be any type that has a size.</p>
				1370	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
				1371	and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
				1372	field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
				1373	instruction.</p>
				1374	<h5>Syntax:</h5>
				1375	<pre> { <type list> }<br></pre>
				1376	<h5>Examples:</h5>
				1377	<table class="layout">
				1378	<tr class="layout">
				1379	<td class="left"><tt>{ i32, i32, i32 }</tt></td>
				1380	<td class="left">A triple of three <tt>i32</tt> values</td>
				1381	</tr><tr class="layout">
				1382	<td class="left"><tt>{ float, i32 (i32) * }</tt></td>
				1383	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1384	second element is a <a href="#t_pointer">pointer</a> to a
				1385	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1386	an <tt>i32</tt>.</td>
				1387	</tr>
				1388	</table>
				1389	</div>
				1390
				1391	<!-- _______________________________________________________________________ -->
				1392	<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
				1393	</div>
				1394	<div class="doc_text">
				1395	<h5>Overview:</h5>
				1396	<p>The packed structure type is used to represent a collection of data members
				1397	together in memory. There is no padding between fields. Further, the alignment
				1398	of a packed structure is 1 byte. The elements of a packed structure may
				1399	be any type that has a size.</p>
				1400	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
				1401	and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
				1402	field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
				1403	instruction.</p>
				1404	<h5>Syntax:</h5>
				1405	<pre> < { <type list> } > <br></pre>
				1406	<h5>Examples:</h5>
				1407	<table class="layout">
				1408	<tr class="layout">
				1409	<td class="left"><tt>< { i32, i32, i32 } ></tt></td>
				1410	<td class="left">A triple of three <tt>i32</tt> values</td>
				1411	</tr><tr class="layout">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1412	<td class="left">
				1413	<tt>< { float, i32 (i32)* } ></tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1414	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1415	second element is a <a href="#t_pointer">pointer</a> to a
				1416	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1417	an <tt>i32</tt>.</td>
				1418	</tr>
				1419	</table>
				1420	</div>
				1421
				1422	<!-- _______________________________________________________________________ -->
				1423	<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
				1424	<div class="doc_text">
				1425	<h5>Overview:</h5>
				1426	<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	1427	reference to another object, which must live in memory. Pointer types may have
				1428	an optional address space attribute defining the target-specific numbered
				1429	address space where the pointed-to object resides. The default address space is
				1430	zero.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1431	<h5>Syntax:</h5>
				1432	<pre> <type> *<br></pre>
				1433	<h5>Examples:</h5>
				1434	<table class="layout">
				1435	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1436	<td class="left"><tt>[4x i32]*</tt></td>
				1437	<td class="left">A <a href="#t_pointer">pointer</a> to <a
				1438	href="#t_array">array</a> of four <tt>i32</tt> values.</td>
				1439	</tr>
				1440	<tr class="layout">
				1441	<td class="left"><tt>i32 (i32 ) </tt></td>
				1442	<td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1443	href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1444	<tt>i32</tt>.</td>
				1445	</tr>
				1446	<tr class="layout">
				1447	<td class="left"><tt>i32 addrspace(5)*</tt></td>
				1448	<td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
				1449	that resides in address space #5.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1450	</tr>
				1451	</table>
				1452	</div>
				1453
				1454	<!-- _______________________________________________________________________ -->
				1455	<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
				1456	<div class="doc_text">
				1457
				1458	<h5>Overview:</h5>
				1459
				1460	<p>A vector type is a simple derived type that represents a vector
				1461	of elements. Vector types are used when multiple primitive data
				1462	are operated in parallel using a single instruction (SIMD).
				1463	A vector type requires a size (number of
				1464	elements) and an underlying primitive data type. Vectors must have a power
				1465	of two length (1, 2, 4, 8, 16 ...). Vector types are
				1466	considered <a href="#t_firstclass">first class</a>.</p>
				1467
				1468	<h5>Syntax:</h5>
				1469
				1470	<pre>
				1471	< <# elements> x <elementtype> >
				1472	</pre>
				1473
				1474	<p>The number of elements is a constant integer value; elementtype may
				1475	be any integer or floating point type.</p>
				1476
				1477	<h5>Examples:</h5>
				1478
				1479	<table class="layout">
				1480	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1481	<td class="left"><tt><4 x i32></tt></td>
				1482	<td class="left">Vector of 4 32-bit integer values.</td>
				1483	</tr>
				1484	<tr class="layout">
				1485	<td class="left"><tt><8 x float></tt></td>
				1486	<td class="left">Vector of 8 32-bit floating-point values.</td>
				1487	</tr>
				1488	<tr class="layout">
				1489	<td class="left"><tt><2 x i64></tt></td>
				1490	<td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1491	</tr>
				1492	</table>
				1493	</div>
				1494
				1495	<!-- _______________________________________________________________________ -->
				1496	<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
				1497	<div class="doc_text">
				1498
				1499	<h5>Overview:</h5>
				1500
				1501	<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen	da0706e	2007-10-14 00:34:53 +0000	[diff] [blame]	1502	corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1503	In LLVM, opaque types can eventually be resolved to any type (not just a
				1504	structure type).</p>
				1505
				1506	<h5>Syntax:</h5>
				1507
				1508	<pre>
				1509	opaque
				1510	</pre>
				1511
				1512	<h5>Examples:</h5>
				1513
				1514	<table class="layout">
				1515	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1516	<td class="left"><tt>opaque</tt></td>
				1517	<td class="left">An opaque type.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1518	</tr>
				1519	</table>
				1520	</div>
				1521
				1522
				1523	<!-- *********************************************************************** -->
				1524	<div class="doc_section"> <a name="constants">Constants</a> </div>
				1525	<!-- *********************************************************************** -->
				1526
				1527	<div class="doc_text">
				1528
				1529	<p>LLVM has several different basic types of constants. This section describes
				1530	them all and their syntax.</p>
				1531
				1532	</div>
				1533
				1534	<!-- ======================================================================= -->
				1535	<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
				1536
				1537	<div class="doc_text">
				1538
				1539	<dl>
				1540	<dt><b>Boolean constants</b></dt>
				1541
				1542	<dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
				1543	constants of the <tt><a href="#t_primitive">i1</a></tt> type.
				1544	</dd>
				1545
				1546	<dt><b>Integer constants</b></dt>
				1547
				1548	<dd>Standard integers (such as '4') are constants of the <a
				1549	href="#t_integer">integer</a> type. Negative numbers may be used with
				1550	integer types.
				1551	</dd>
				1552
				1553	<dt><b>Floating point constants</b></dt>
				1554
				1555	<dd>Floating point constants use standard decimal notation (e.g. 123.421),
				1556	exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	1557	notation (see below). The assembler requires the exact decimal value of
				1558	a floating-point constant. For example, the assembler accepts 1.25 but
				1559	rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
				1560	constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1561
				1562	<dt><b>Null pointer constants</b></dt>
				1563
				1564	<dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
				1565	and must be of <a href="#t_pointer">pointer type</a>.</dd>
				1566
				1567	</dl>
				1568
				1569	<p>The one non-intuitive notation for constants is the optional hexadecimal form
				1570	of floating point constants. For example, the form '<tt>double
				1571	0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
				1572	4.5e+15</tt>'. The only time hexadecimal floating point constants are required
				1573	(and the only time that they are generated by the disassembler) is when a
				1574	floating point constant must be emitted but it cannot be represented as a
				1575	decimal floating point number. For example, NaN's, infinities, and other
				1576	special values are represented in their IEEE hexadecimal format so that
				1577	assembly and disassembly do not cause any bits to change in the constants.</p>
				1578
				1579	</div>
				1580
				1581	<!-- ======================================================================= -->
				1582	<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
				1583	</div>
				1584
				1585	<div class="doc_text">
				1586	<p>Aggregate constants arise from aggregation of simple constants
				1587	and smaller aggregate constants.</p>
				1588
				1589	<dl>
				1590	<dt><b>Structure constants</b></dt>
				1591
				1592	<dd>Structure constants are represented with notation similar to structure
				1593	type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner	6c8de96	2007-12-25 20:34:52 +0000	[diff] [blame]	1594	(<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
				1595	where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1596	must have <a href="#t_struct">structure type</a>, and the number and
				1597	types of elements must match those specified by the type.
				1598	</dd>
				1599
				1600	<dt><b>Array constants</b></dt>
				1601
				1602	<dd>Array constants are represented with notation similar to array type
				1603	definitions (a comma separated list of elements, surrounded by square brackets
				1604	(<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
				1605	constants must have <a href="#t_array">array type</a>, and the number and
				1606	types of elements must match those specified by the type.
				1607	</dd>
				1608
				1609	<dt><b>Vector constants</b></dt>
				1610
				1611	<dd>Vector constants are represented with notation similar to vector type
				1612	definitions (a comma separated list of elements, surrounded by
				1613	less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32 42,
				1614	i32 11, i32 74, i32 100 ></tt>". Vector constants must have <a
				1615	href="#t_vector">vector type</a>, and the number and types of elements must
				1616	match those specified by the type.
				1617	</dd>
				1618
				1619	<dt><b>Zero initialization</b></dt>
				1620
				1621	<dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
				1622	value to zero of <em>any</em> type, including scalar and aggregate types.
				1623	This is often used to avoid having to print large zero initializers (e.g. for
				1624	large arrays) and is always exactly equivalent to using explicit zero
				1625	initializers.
				1626	</dd>
				1627	</dl>
				1628
				1629	</div>
				1630
				1631	<!-- ======================================================================= -->
				1632	<div class="doc_subsection">
				1633	<a name="globalconstants">Global Variable and Function Addresses</a>
				1634	</div>
				1635
				1636	<div class="doc_text">
				1637
				1638	<p>The addresses of <a href="#globalvars">global variables</a> and <a
				1639	href="#functionstructure">functions</a> are always implicitly valid (link-time)
				1640	constants. These constants are explicitly referenced when the <a
				1641	href="#identifiers">identifier for the global</a> is used and always have <a
				1642	href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
				1643	file:</p>
				1644
				1645	<div class="doc_code">
				1646	<pre>
				1647	@X = global i32 17
				1648	@Y = global i32 42
				1649	@Z = global [2 x i32] [ i32 @X, i32* @Y ]
				1650	</pre>
				1651	</div>
				1652
				1653	</div>
				1654
				1655	<!-- ======================================================================= -->
				1656	<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
				1657	<div class="doc_text">
				1658	<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
				1659	no specific value. Undefined values may be of any type and be used anywhere
				1660	a constant is permitted.</p>
				1661
				1662	<p>Undefined values indicate to the compiler that the program is well defined
				1663	no matter what value is used, giving the compiler more freedom to optimize.
				1664	</p>
				1665	</div>
				1666
				1667	<!-- ======================================================================= -->
				1668	<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
				1669	</div>
				1670
				1671	<div class="doc_text">
				1672
				1673	<p>Constant expressions are used to allow expressions involving other constants
				1674	to be used as constants. Constant expressions may be of any <a
				1675	href="#t_firstclass">first class</a> type and may involve any LLVM operation
				1676	that does not have side effects (e.g. load and call are not supported). The
				1677	following is the syntax for constant expressions:</p>
				1678
				1679	<dl>
				1680	<dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
				1681	<dd>Truncate a constant to another type. The bit size of CST must be larger
				1682	than the bit size of TYPE. Both types must be integers.</dd>
				1683
				1684	<dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
				1685	<dd>Zero extend a constant to another type. The bit size of CST must be
				1686	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1687
				1688	<dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
				1689	<dd>Sign extend a constant to another type. The bit size of CST must be
				1690	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1691
				1692	<dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
				1693	<dd>Truncate a floating point constant to another floating point type. The
				1694	size of CST must be larger than the size of TYPE. Both types must be
				1695	floating point.</dd>
				1696
				1697	<dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
				1698	<dd>Floating point extend a constant to another type. The size of CST must be
				1699	smaller or equal to the size of TYPE. Both types must be floating point.</dd>
				1700
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	1701	<dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1702	<dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1703	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1704	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1705	of the same number of elements. If the value won't fit in the integer type,
				1706	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1707
				1708	<dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
				1709	<dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1710	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1711	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1712	of the same number of elements. If the value won't fit in the integer type,
				1713	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1714
				1715	<dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
				1716	<dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1717	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1718	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1719	of the same number of elements. If the value won't fit in the floating point
				1720	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1721
				1722	<dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
				1723	<dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1724	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1725	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1726	of the same number of elements. If the value won't fit in the floating point
				1727	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1728
				1729	<dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
				1730	<dd>Convert a pointer typed constant to the corresponding integer constant
				1731	TYPE must be an integer type. CST must be of pointer type. The CST value is
				1732	zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
				1733
				1734	<dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
				1735	<dd>Convert a integer constant to a pointer constant. TYPE must be a
				1736	pointer type. CST must be of integer type. The CST value is zero extended,
				1737	truncated, or unchanged to make it fit in a pointer size. This one is
				1738	<i>really</i> dangerous!</dd>
				1739
				1740	<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
				1741	<dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
				1742	identical (same number of bits). The conversion is done as if the CST value
				1743	was stored to memory and read back as TYPE. In other words, no bits change
				1744	with this operator, just the type. This can be used for conversion of
				1745	vector types to any other type, as long as they have the same bit width. For
Dan Gohman	7305fa0	2008-09-08 16:45:59 +0000	[diff] [blame]	1746	pointers it is only valid to cast to another pointer type. It is not valid
				1747	to bitcast to or from an aggregate type.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1748	</dd>
				1749
				1750	<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
				1751
				1752	<dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
				1753	constants. As with the <a href="#i_getelementptr">getelementptr</a>
				1754	instruction, the index list may have zero or more indexes, which are required
				1755	to make sense for the type of "CSTPTR".</dd>
				1756
				1757	<dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
				1758
				1759	<dd>Perform the <a href="#i_select">select operation</a> on
				1760	constants.</dd>
				1761
				1762	<dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
				1763	<dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
				1764
				1765	<dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1766	<dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
				1767
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	1768	<dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
				1769	<dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
				1770
				1771	<dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1772	<dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
				1773
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1774	<dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
				1775
				1776	<dd>Perform the <a href="#i_extractelement">extractelement
				1777	operation</a> on constants.
				1778
				1779	<dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
				1780
				1781	<dd>Perform the <a href="#i_insertelement">insertelement
				1782	operation</a> on constants.</dd>
				1783
				1784
				1785	<dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
				1786
				1787	<dd>Perform the <a href="#i_shufflevector">shufflevector
				1788	operation</a> on constants.</dd>
				1789
				1790	<dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
				1791
				1792	<dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
				1793	be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
				1794	binary</a> operations. The constraints on operands are the same as those for
				1795	the corresponding instruction (e.g. no bitwise operations on floating point
				1796	values are allowed).</dd>
				1797	</dl>
				1798	</div>
				1799
				1800	<!-- *********************************************************************** -->
				1801	<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
				1802	<!-- *********************************************************************** -->
				1803
				1804	<!-- ======================================================================= -->
				1805	<div class="doc_subsection">
				1806	<a name="inlineasm">Inline Assembler Expressions</a>
				1807	</div>
				1808
				1809	<div class="doc_text">
				1810
				1811	<p>
				1812	LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
				1813	Module-Level Inline Assembly</a>) through the use of a special value. This
				1814	value represents the inline assembler as a string (containing the instructions
				1815	to emit), a list of operand constraints (stored as a string), and a flag that
				1816	indicates whether or not the inline asm expression has side effects. An example
				1817	inline assembler expression is:
				1818	</p>
				1819
				1820	<div class="doc_code">
				1821	<pre>
				1822	i32 (i32) asm "bswap $0", "=r,r"
				1823	</pre>
				1824	</div>
				1825
				1826	<p>
				1827	Inline assembler expressions may <b>only</b> be used as the callee operand of
				1828	a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
				1829	</p>
				1830
				1831	<div class="doc_code">
				1832	<pre>
				1833	%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
				1834	</pre>
				1835	</div>
				1836
				1837	<p>
				1838	Inline asms with side effects not visible in the constraint list must be marked
				1839	as having side effects. This is done through the use of the
				1840	'<tt>sideeffect</tt>' keyword, like so:
				1841	</p>
				1842
				1843	<div class="doc_code">
				1844	<pre>
				1845	call void asm sideeffect "eieio", ""()
				1846	</pre>
				1847	</div>
				1848
				1849	<p>TODO: The format of the asm and constraints string still need to be
				1850	documented here. Constraints on what can be done (e.g. duplication, moving, etc
				1851	need to be documented).
				1852	</p>
				1853
				1854	</div>
				1855
				1856	<!-- *********************************************************************** -->
				1857	<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
				1858	<!-- *********************************************************************** -->
				1859
				1860	<div class="doc_text">
				1861
				1862	<p>The LLVM instruction set consists of several different
				1863	classifications of instructions: <a href="#terminators">terminator
				1864	instructions</a>, <a href="#binaryops">binary instructions</a>,
				1865	<a href="#bitwiseops">bitwise binary instructions</a>, <a
				1866	href="#memoryops">memory instructions</a>, and <a href="#otherops">other
				1867	instructions</a>.</p>
				1868
				1869	</div>
				1870
				1871	<!-- ======================================================================= -->
				1872	<div class="doc_subsection"> <a name="terminators">Terminator
				1873	Instructions</a> </div>
				1874
				1875	<div class="doc_text">
				1876
				1877	<p>As mentioned <a href="#functionstructure">previously</a>, every
				1878	basic block in a program ends with a "Terminator" instruction, which
				1879	indicates which block should be executed after the current block is
				1880	finished. These terminator instructions typically yield a '<tt>void</tt>'
				1881	value: they produce control flow, not values (the one exception being
				1882	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
				1883	<p>There are six different terminator instructions: the '<a
				1884	href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
				1885	instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
				1886	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
				1887	href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
				1888	href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
				1889
				1890	</div>
				1891
				1892	<!-- _______________________________________________________________________ -->
				1893	<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
				1894	Instruction</a> </div>
				1895	<div class="doc_text">
				1896	<h5>Syntax:</h5>
				1897	<pre> ret <type> <value> <i>; Return a value from a non-void function</i>
				1898	ret void <i>; Return from void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1899	ret <type> <value>, <type> <value> <i>; Return two values from a non-void function </i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1900	</pre>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1901
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1902	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1903
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1904	<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
				1905	value) from a function back to the caller.</p>
				1906	<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1907	returns value(s) and then causes control flow, and one that just causes
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1908	control flow to occur.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1909
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1910	<h5>Arguments:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1911
				1912	<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
				1913	The type of each return value must be a '<a href="#t_firstclass">first
				1914	class</a>' type. Note that a function is not <a href="#wellformed">well
				1915	formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
				1916	function that returns values that do not match the return type of the
				1917	function.</p>
				1918
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1919	<h5>Semantics:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1920
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1921	<p>When the '<tt>ret</tt>' instruction is executed, control flow
				1922	returns back to the calling function's context. If the caller is a "<a
				1923	href="#i_call"><tt>call</tt></a>" instruction, execution continues at
				1924	the instruction after the call. If the caller was an "<a
				1925	href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
				1926	at the beginning of the "normal" destination block. If the instruction
				1927	returns a value, that value shall set the call or invoke instruction's
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1928	return value. If the instruction returns multiple values then these
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	1929	values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
				1930	</a>' instruction.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1931
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1932	<h5>Example:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1933
				1934	<pre>
				1935	ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1936	ret void <i>; Return from a void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1937	ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1938	</pre>
				1939	</div>
				1940	<!-- _______________________________________________________________________ -->
				1941	<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
				1942	<div class="doc_text">
				1943	<h5>Syntax:</h5>
				1944	<pre> br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
				1945	</pre>
				1946	<h5>Overview:</h5>
				1947	<p>The '<tt>br</tt>' instruction is used to cause control flow to
				1948	transfer to a different basic block in the current function. There are
				1949	two forms of this instruction, corresponding to a conditional branch
				1950	and an unconditional branch.</p>
				1951	<h5>Arguments:</h5>
				1952	<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
				1953	single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
				1954	unconditional form of the '<tt>br</tt>' instruction takes a single
				1955	'<tt>label</tt>' value as a target.</p>
				1956	<h5>Semantics:</h5>
				1957	<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
				1958	argument is evaluated. If the value is <tt>true</tt>, control flows
				1959	to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
				1960	control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
				1961	<h5>Example:</h5>
				1962	<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
				1963	href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
				1964	</div>
				1965	<!-- _______________________________________________________________________ -->
				1966	<div class="doc_subsubsection">
				1967	<a name="i_switch">'<tt>switch</tt>' Instruction</a>
				1968	</div>
				1969
				1970	<div class="doc_text">
				1971	<h5>Syntax:</h5>
				1972
				1973	<pre>
				1974	switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
				1975	</pre>
				1976
				1977	<h5>Overview:</h5>
				1978
				1979	<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
				1980	several different places. It is a generalization of the '<tt>br</tt>'
				1981	instruction, allowing a branch to occur to one of many possible
				1982	destinations.</p>
				1983
				1984
				1985	<h5>Arguments:</h5>
				1986
				1987	<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
				1988	comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
				1989	an array of pairs of comparison value constants and '<tt>label</tt>'s. The
				1990	table is not allowed to contain duplicate constant entries.</p>
				1991
				1992	<h5>Semantics:</h5>
				1993
				1994	<p>The <tt>switch</tt> instruction specifies a table of values and
				1995	destinations. When the '<tt>switch</tt>' instruction is executed, this
				1996	table is searched for the given value. If the value is found, control flow is
				1997	transfered to the corresponding destination; otherwise, control flow is
				1998	transfered to the default destination.</p>
				1999
				2000	<h5>Implementation:</h5>
				2001
				2002	<p>Depending on properties of the target machine and the particular
				2003	<tt>switch</tt> instruction, this instruction may be code generated in different
				2004	ways. For example, it could be generated as a series of chained conditional
				2005	branches or with a lookup table.</p>
				2006
				2007	<h5>Example:</h5>
				2008
				2009	<pre>
				2010	<i>; Emulate a conditional br instruction</i>
				2011	%Val = <a href="#i_zext">zext</a> i1 %value to i32
				2012	switch i32 %Val, label %truedest [i32 0, label %falsedest ]
				2013
				2014	<i>; Emulate an unconditional br instruction</i>
				2015	switch i32 0, label %dest [ ]
				2016
				2017	<i>; Implement a jump table:</i>
				2018	switch i32 %val, label %otherwise [ i32 0, label %onzero
				2019	i32 1, label %onone
				2020	i32 2, label %ontwo ]
				2021	</pre>
				2022	</div>
				2023
				2024	<!-- _______________________________________________________________________ -->
				2025	<div class="doc_subsubsection">
				2026	<a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
				2027	</div>
				2028
				2029	<div class="doc_text">
				2030
				2031	<h5>Syntax:</h5>
				2032
				2033	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2034	<result> = invoke [<a href="#callingconv">cconv</a>] <ptr to function ty> <function ptr val>(<function args>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2035	to label <normal label> unwind label <exception label>
				2036	</pre>
				2037
				2038	<h5>Overview:</h5>
				2039
				2040	<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
				2041	function, with the possibility of control flow transfer to either the
				2042	'<tt>normal</tt>' label or the
				2043	'<tt>exception</tt>' label. If the callee function returns with the
				2044	"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
				2045	"normal" label. If the callee (or any indirect callees) returns with the "<a
				2046	href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	2047	continued at the dynamically nearest "exception" label. If the callee function
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	2048	returns multiple values then individual return values are only accessible through
				2049	a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2050
				2051	<h5>Arguments:</h5>
				2052
				2053	<p>This instruction requires several arguments:</p>
				2054
				2055	<ol>
				2056	<li>
				2057	The optional "cconv" marker indicates which <a href="#callingconv">calling
				2058	convention</a> the call should use. If none is specified, the call defaults
				2059	to using C calling conventions.
				2060	</li>
				2061	<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
				2062	function value being invoked. In most cases, this is a direct function
				2063	invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
				2064	an arbitrary pointer to function value.
				2065	</li>
				2066
				2067	<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
				2068	function to be invoked. </li>
				2069
				2070	<li>'<tt>function args</tt>': argument list whose types match the function
				2071	signature argument types. If the function signature indicates the function
				2072	accepts a variable number of arguments, the extra arguments can be
				2073	specified. </li>
				2074
				2075	<li>'<tt>normal label</tt>': the label reached when the called function
				2076	executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
				2077
				2078	<li>'<tt>exception label</tt>': the label reached when a callee returns with
				2079	the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
				2080
				2081	</ol>
				2082
				2083	<h5>Semantics:</h5>
				2084
				2085	<p>This instruction is designed to operate as a standard '<tt><a
				2086	href="#i_call">call</a></tt>' instruction in most regards. The primary
				2087	difference is that it establishes an association with a label, which is used by
				2088	the runtime library to unwind the stack.</p>
				2089
				2090	<p>This instruction is used in languages with destructors to ensure that proper
				2091	cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
				2092	exception. Additionally, this is important for implementation of
				2093	'<tt>catch</tt>' clauses in high-level languages that support them.</p>
				2094
				2095	<h5>Example:</h5>
				2096	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2097	%retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2098	unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2099	%retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2100	unwind label %TestCleanup <i>; {i32}:retval set</i>
				2101	</pre>
				2102	</div>
				2103
				2104
				2105	<!-- _______________________________________________________________________ -->
				2106
				2107	<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
				2108	Instruction</a> </div>
				2109
				2110	<div class="doc_text">
				2111
				2112	<h5>Syntax:</h5>
				2113	<pre>
				2114	unwind
				2115	</pre>
				2116
				2117	<h5>Overview:</h5>
				2118
				2119	<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
				2120	at the first callee in the dynamic call stack which used an <a
				2121	href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
				2122	primarily used to implement exception handling.</p>
				2123
				2124	<h5>Semantics:</h5>
				2125
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	2126	<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2127	immediately halt. The dynamic call stack is then searched for the first <a
				2128	href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
				2129	execution continues at the "exceptional" destination block specified by the
				2130	<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
				2131	dynamic call chain, undefined behavior results.</p>
				2132	</div>
				2133
				2134	<!-- _______________________________________________________________________ -->
				2135
				2136	<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
				2137	Instruction</a> </div>
				2138
				2139	<div class="doc_text">
				2140
				2141	<h5>Syntax:</h5>
				2142	<pre>
				2143	unreachable
				2144	</pre>
				2145
				2146	<h5>Overview:</h5>
				2147
				2148	<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
				2149	instruction is used to inform the optimizer that a particular portion of the
				2150	code is not reachable. This can be used to indicate that the code after a
				2151	no-return function cannot be reached, and other facts.</p>
				2152
				2153	<h5>Semantics:</h5>
				2154
				2155	<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
				2156	</div>
				2157
				2158
				2159
				2160	<!-- ======================================================================= -->
				2161	<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
				2162	<div class="doc_text">
				2163	<p>Binary operators are used to do most of the computation in a
Chris Lattner	ab596d9	2008-04-01 18:47:32 +0000	[diff] [blame]	2164	program. They require two operands of the same type, execute an operation on them, and
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2165	produce a single value. The operands might represent
				2166	multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattner	ab596d9	2008-04-01 18:47:32 +0000	[diff] [blame]	2167	The result value has the same type as its operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2168	<p>There are several different binary operators:</p>
				2169	</div>
				2170	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2171	<div class="doc_subsubsection">
				2172	<a name="i_add">'<tt>add</tt>' Instruction</a>
				2173	</div>
				2174
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2175	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2176
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2177	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2178
				2179	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2180	<result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2181	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2182
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2183	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2184
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2185	<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2186
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2187	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2188
				2189	<p>The two arguments to the '<tt>add</tt>' instruction must be <a
				2190	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
				2191	<a href="#t_vector">vector</a> values. Both arguments must have identical
				2192	types.</p>
				2193
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2194	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2195
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2196	<p>The value produced is the integer or floating point sum of the two
				2197	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2198
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2199	<p>If an integer sum has unsigned overflow, the result returned is the
				2200	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2201	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2202
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2203	<p>Because LLVM integers use a two's complement representation, this
				2204	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2205
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2206	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2207
				2208	<pre>
				2209	<result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2210	</pre>
				2211	</div>
				2212	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2213	<div class="doc_subsubsection">
				2214	<a name="i_sub">'<tt>sub</tt>' Instruction</a>
				2215	</div>
				2216
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2217	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2218
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2219	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2220
				2221	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2222	<result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2223	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2224
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2225	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2226
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2227	<p>The '<tt>sub</tt>' instruction returns the difference of its two
				2228	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2229
				2230	<p>Note that the '<tt>sub</tt>' instruction is used to represent the
				2231	'<tt>neg</tt>' instruction present in most other intermediate
				2232	representations.</p>
				2233
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2234	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2235
				2236	<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
				2237	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2238	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2239	types.</p>
				2240
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2241	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2242
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2243	<p>The value produced is the integer or floating point difference of
				2244	the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2245
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2246	<p>If an integer difference has unsigned overflow, the result returned is the
				2247	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2248	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2249
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2250	<p>Because LLVM integers use a two's complement representation, this
				2251	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2252
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2253	<h5>Example:</h5>
				2254	<pre>
				2255	<result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
				2256	<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
				2257	</pre>
				2258	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2259
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2260	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2261	<div class="doc_subsubsection">
				2262	<a name="i_mul">'<tt>mul</tt>' Instruction</a>
				2263	</div>
				2264
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2265	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2266
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2267	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2268	<pre> <result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2269	</pre>
				2270	<h5>Overview:</h5>
				2271	<p>The '<tt>mul</tt>' instruction returns the product of its two
				2272	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2273
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2274	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2275
				2276	<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
				2277	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2278	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2279	types.</p>
				2280
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2281	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2282
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2283	<p>The value produced is the integer or floating point product of the
				2284	two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2285
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2286	<p>If the result of an integer multiplication has unsigned overflow,
				2287	the result returned is the mathematical result modulo
				2288	2<sup>n</sup>, where n is the bit width of the result.</p>
				2289	<p>Because LLVM integers use a two's complement representation, and the
				2290	result is the same width as the operands, this instruction returns the
				2291	correct result for both signed and unsigned integers. If a full product
				2292	(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
				2293	should be sign-extended or zero-extended as appropriate to the
				2294	width of the full product.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2295	<h5>Example:</h5>
				2296	<pre> <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
				2297	</pre>
				2298	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2299
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2300	<!-- _______________________________________________________________________ -->
				2301	<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
				2302	</a></div>
				2303	<div class="doc_text">
				2304	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2305	<pre> <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2306	</pre>
				2307	<h5>Overview:</h5>
				2308	<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
				2309	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2310
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2311	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2312
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2313	<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2314	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2315	values. Both arguments must have identical types.</p>
				2316
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2317	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2318
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2319	<p>The value produced is the unsigned integer quotient of the two operands.</p>
				2320	<p>Note that unsigned integer division and signed integer division are distinct
				2321	operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
				2322	<p>Division by zero leads to undefined behavior.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2323	<h5>Example:</h5>
				2324	<pre> <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2325	</pre>
				2326	</div>
				2327	<!-- _______________________________________________________________________ -->
				2328	<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
				2329	</a> </div>
				2330	<div class="doc_text">
				2331	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2332	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2333	<result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2334	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2335
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2336	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2337
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2338	<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
				2339	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2340
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2341	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2342
				2343	<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
				2344	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2345	values. Both arguments must have identical types.</p>
				2346
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2347	<h5>Semantics:</h5>
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2348	<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2349	<p>Note that signed integer division and unsigned integer division are distinct
				2350	operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
				2351	<p>Division by zero leads to undefined behavior. Overflow also leads to
				2352	undefined behavior; this is a rare case, but can occur, for example,
				2353	by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2354	<h5>Example:</h5>
				2355	<pre> <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2356	</pre>
				2357	</div>
				2358	<!-- _______________________________________________________________________ -->
				2359	<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
				2360	Instruction</a> </div>
				2361	<div class="doc_text">
				2362	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2363	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2364	<result> = fdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2365	</pre>
				2366	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2367
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2368	<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
				2369	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2370
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2371	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2372
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2373	<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2374	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2375	of floating point values. Both arguments must have identical types.</p>
				2376
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2377	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2378
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2379	<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2380
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2381	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2382
				2383	<pre>
				2384	<result> = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2385	</pre>
				2386	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2387
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2388	<!-- _______________________________________________________________________ -->
				2389	<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
				2390	</div>
				2391	<div class="doc_text">
				2392	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2393	<pre> <result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2394	</pre>
				2395	<h5>Overview:</h5>
				2396	<p>The '<tt>urem</tt>' instruction returns the remainder from the
				2397	unsigned division of its two arguments.</p>
				2398	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2399	<p>The two arguments to the '<tt>urem</tt>' instruction must be
				2400	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2401	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2402	<h5>Semantics:</h5>
				2403	<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2404	This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2405	<p>Note that unsigned integer remainder and signed integer remainder are
				2406	distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
				2407	<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2408	<h5>Example:</h5>
				2409	<pre> <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2410	</pre>
				2411
				2412	</div>
				2413	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2414	<div class="doc_subsubsection">
				2415	<a name="i_srem">'<tt>srem</tt>' Instruction</a>
				2416	</div>
				2417
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2418	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2419
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2420	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2421
				2422	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2423	<result> = srem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2424	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2425
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2426	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2427
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2428	<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman	3e3fd8c	2007-11-05 23:35:22 +0000	[diff] [blame]	2429	signed division of its two operands. This instruction can also take
				2430	<a href="#t_vector">vector</a> versions of the values in which case
				2431	the elements must be integers.</p>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	2432
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2433	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2434
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2435	<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2436	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2437	values. Both arguments must have identical types.</p>
				2438
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2439	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2440
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2441	<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2442	has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
				2443	operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2444	a value. For more information about the difference, see <a
				2445	href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
				2446	Math Forum</a>. For a table of how this is implemented in various languages,
				2447	please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
				2448	Wikipedia: modulo operation</a>.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2449	<p>Note that signed integer remainder and unsigned integer remainder are
				2450	distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
				2451	<p>Taking the remainder of a division by zero leads to undefined behavior.
				2452	Overflow also leads to undefined behavior; this is a rare case, but can occur,
				2453	for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
				2454	(The remainder doesn't actually overflow, but this rule lets srem be
				2455	implemented using instructions that return both the result of the division
				2456	and the remainder.)</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2457	<h5>Example:</h5>
				2458	<pre> <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2459	</pre>
				2460
				2461	</div>
				2462	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2463	<div class="doc_subsubsection">
				2464	<a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
				2465
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2466	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2467
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2468	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2469	<pre> <result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2470	</pre>
				2471	<h5>Overview:</h5>
				2472	<p>The '<tt>frem</tt>' instruction returns the remainder from the
				2473	division of its two operands.</p>
				2474	<h5>Arguments:</h5>
				2475	<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2476	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2477	of floating point values. Both arguments must have identical types.</p>
				2478
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2479	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2480
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2481	<p>This instruction returns the <i>remainder</i> of a division.
				2482	The remainder has the same sign as the dividend.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2483
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2484	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2485
				2486	<pre>
				2487	<result> = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2488	</pre>
				2489	</div>
				2490
				2491	<!-- ======================================================================= -->
				2492	<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
				2493	Operations</a> </div>
				2494	<div class="doc_text">
				2495	<p>Bitwise binary operators are used to do various forms of
				2496	bit-twiddling in a program. They are generally very efficient
				2497	instructions and can commonly be strength reduced from other
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2498	instructions. They require two operands of the same type, execute an operation on them,
				2499	and produce a single value. The resulting value is the same type as its operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2500	</div>
				2501
				2502	<!-- _______________________________________________________________________ -->
				2503	<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
				2504	Instruction</a> </div>
				2505	<div class="doc_text">
				2506	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2507	<pre> <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2508	</pre>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2509
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2510	<h5>Overview:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2511
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2512	<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
				2513	the left a specified number of bits.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2514
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2515	<h5>Arguments:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2516
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2517	<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begeman	bb1ce94	2008-07-29 15:49:41 +0000	[diff] [blame]	2518	href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2519	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2520
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2521	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2522
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2523	<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
				2524	where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
				2525	equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2526
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2527	<h5>Example:</h5><pre>
				2528	<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
				2529	<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
				2530	<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2531	<result> = shl i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2532	</pre>
				2533	</div>
				2534	<!-- _______________________________________________________________________ -->
				2535	<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
				2536	Instruction</a> </div>
				2537	<div class="doc_text">
				2538	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2539	<pre> <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2540	</pre>
				2541
				2542	<h5>Overview:</h5>
				2543	<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
				2544	operand shifted to the right a specified number of bits with zero fill.</p>
				2545
				2546	<h5>Arguments:</h5>
				2547	<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begeman	bb1ce94	2008-07-29 15:49:41 +0000	[diff] [blame]	2548	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2549	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2550
				2551	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2552
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2553	<p>This instruction always performs a logical shift right operation. The most
				2554	significant bits of the result will be filled with zero bits after the
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2555	shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
				2556	the number of bits in <tt>op1</tt>, the result is undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2557
				2558	<h5>Example:</h5>
				2559	<pre>
				2560	<result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2561	<result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2562	<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2563	<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2564	<result> = lshr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2565	</pre>
				2566	</div>
				2567
				2568	<!-- _______________________________________________________________________ -->
				2569	<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
				2570	Instruction</a> </div>
				2571	<div class="doc_text">
				2572
				2573	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2574	<pre> <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2575	</pre>
				2576
				2577	<h5>Overview:</h5>
				2578	<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
				2579	operand shifted to the right a specified number of bits with sign extension.</p>
				2580
				2581	<h5>Arguments:</h5>
				2582	<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begeman	bb1ce94	2008-07-29 15:49:41 +0000	[diff] [blame]	2583	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2584	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2585
				2586	<h5>Semantics:</h5>
				2587	<p>This instruction always performs an arithmetic shift right operation,
				2588	The most significant bits of the result will be filled with the sign bit
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2589	of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
				2590	larger than the number of bits in <tt>op1</tt>, the result is undefined.
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2591	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2592
				2593	<h5>Example:</h5>
				2594	<pre>
				2595	<result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2596	<result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2597	<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2598	<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2599	<result> = ashr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2600	</pre>
				2601	</div>
				2602
				2603	<!-- _______________________________________________________________________ -->
				2604	<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
				2605	Instruction</a> </div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2606
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2607	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2608
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2609	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2610
				2611	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2612	<result> = and <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2613	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2614
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2615	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2616
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2617	<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
				2618	its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2619
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2620	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2621
				2622	<p>The two arguments to the '<tt>and</tt>' instruction must be
				2623	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2624	values. Both arguments must have identical types.</p>
				2625
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2626	<h5>Semantics:</h5>
				2627	<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
				2628	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2629	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2630	<table border="1" cellspacing="0" cellpadding="4">
				2631	<tbody>
				2632	<tr>
				2633	<td>In0</td>
				2634	<td>In1</td>
				2635	<td>Out</td>
				2636	</tr>
				2637	<tr>
				2638	<td>0</td>
				2639	<td>0</td>
				2640	<td>0</td>
				2641	</tr>
				2642	<tr>
				2643	<td>0</td>
				2644	<td>1</td>
				2645	<td>0</td>
				2646	</tr>
				2647	<tr>
				2648	<td>1</td>
				2649	<td>0</td>
				2650	<td>0</td>
				2651	</tr>
				2652	<tr>
				2653	<td>1</td>
				2654	<td>1</td>
				2655	<td>1</td>
				2656	</tr>
				2657	</tbody>
				2658	</table>
				2659	</div>
				2660	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2661	<pre>
				2662	<result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2663	<result> = and i32 15, 40 <i>; yields {i32}:result = 8</i>
				2664	<result> = and i32 4, 8 <i>; yields {i32}:result = 0</i>
				2665	</pre>
				2666	</div>
				2667	<!-- _______________________________________________________________________ -->
				2668	<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
				2669	<div class="doc_text">
				2670	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2671	<pre> <result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2672	</pre>
				2673	<h5>Overview:</h5>
				2674	<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
				2675	or of its two operands.</p>
				2676	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2677
				2678	<p>The two arguments to the '<tt>or</tt>' instruction must be
				2679	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2680	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2681	<h5>Semantics:</h5>
				2682	<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
				2683	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2684	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2685	<table border="1" cellspacing="0" cellpadding="4">
				2686	<tbody>
				2687	<tr>
				2688	<td>In0</td>
				2689	<td>In1</td>
				2690	<td>Out</td>
				2691	</tr>
				2692	<tr>
				2693	<td>0</td>
				2694	<td>0</td>
				2695	<td>0</td>
				2696	</tr>
				2697	<tr>
				2698	<td>0</td>
				2699	<td>1</td>
				2700	<td>1</td>
				2701	</tr>
				2702	<tr>
				2703	<td>1</td>
				2704	<td>0</td>
				2705	<td>1</td>
				2706	</tr>
				2707	<tr>
				2708	<td>1</td>
				2709	<td>1</td>
				2710	<td>1</td>
				2711	</tr>
				2712	</tbody>
				2713	</table>
				2714	</div>
				2715	<h5>Example:</h5>
				2716	<pre> <result> = or i32 4, %var <i>; yields {i32}:result = 4 \| %var</i>
				2717	<result> = or i32 15, 40 <i>; yields {i32}:result = 47</i>
				2718	<result> = or i32 4, 8 <i>; yields {i32}:result = 12</i>
				2719	</pre>
				2720	</div>
				2721	<!-- _______________________________________________________________________ -->
				2722	<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
				2723	Instruction</a> </div>
				2724	<div class="doc_text">
				2725	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2726	<pre> <result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2727	</pre>
				2728	<h5>Overview:</h5>
				2729	<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
				2730	or of its two operands. The <tt>xor</tt> is used to implement the
				2731	"one's complement" operation, which is the "~" operator in C.</p>
				2732	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2733	<p>The two arguments to the '<tt>xor</tt>' instruction must be
				2734	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2735	values. Both arguments must have identical types.</p>
				2736
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2737	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2738
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2739	<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
				2740	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2741	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2742	<table border="1" cellspacing="0" cellpadding="4">
				2743	<tbody>
				2744	<tr>
				2745	<td>In0</td>
				2746	<td>In1</td>
				2747	<td>Out</td>
				2748	</tr>
				2749	<tr>
				2750	<td>0</td>
				2751	<td>0</td>
				2752	<td>0</td>
				2753	</tr>
				2754	<tr>
				2755	<td>0</td>
				2756	<td>1</td>
				2757	<td>1</td>
				2758	</tr>
				2759	<tr>
				2760	<td>1</td>
				2761	<td>0</td>
				2762	<td>1</td>
				2763	</tr>
				2764	<tr>
				2765	<td>1</td>
				2766	<td>1</td>
				2767	<td>0</td>
				2768	</tr>
				2769	</tbody>
				2770	</table>
				2771	</div>
				2772	<p> </p>
				2773	<h5>Example:</h5>
				2774	<pre> <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
				2775	<result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
				2776	<result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
				2777	<result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
				2778	</pre>
				2779	</div>
				2780
				2781	<!-- ======================================================================= -->
				2782	<div class="doc_subsection">
				2783	<a name="vectorops">Vector Operations</a>
				2784	</div>
				2785
				2786	<div class="doc_text">
				2787
				2788	<p>LLVM supports several instructions to represent vector operations in a
				2789	target-independent manner. These instructions cover the element-access and
				2790	vector-specific operations needed to process vectors effectively. While LLVM
				2791	does directly support these vector operations, many sophisticated algorithms
				2792	will want to use target-specific intrinsics to take full advantage of a specific
				2793	target.</p>
				2794
				2795	</div>
				2796
				2797	<!-- _______________________________________________________________________ -->
				2798	<div class="doc_subsubsection">
				2799	<a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
				2800	</div>
				2801
				2802	<div class="doc_text">
				2803
				2804	<h5>Syntax:</h5>
				2805
				2806	<pre>
				2807	<result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
				2808	</pre>
				2809
				2810	<h5>Overview:</h5>
				2811
				2812	<p>
				2813	The '<tt>extractelement</tt>' instruction extracts a single scalar
				2814	element from a vector at a specified index.
				2815	</p>
				2816
				2817
				2818	<h5>Arguments:</h5>
				2819
				2820	<p>
				2821	The first operand of an '<tt>extractelement</tt>' instruction is a
				2822	value of <a href="#t_vector">vector</a> type. The second operand is
				2823	an index indicating the position from which to extract the element.
				2824	The index may be a variable.</p>
				2825
				2826	<h5>Semantics:</h5>
				2827
				2828	<p>
				2829	The result is a scalar of the same type as the element type of
				2830	<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
				2831	<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
				2832	results are undefined.
				2833	</p>
				2834
				2835	<h5>Example:</h5>
				2836
				2837	<pre>
				2838	%result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
				2839	</pre>
				2840	</div>
				2841
				2842
				2843	<!-- _______________________________________________________________________ -->
				2844	<div class="doc_subsubsection">
				2845	<a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
				2846	</div>
				2847
				2848	<div class="doc_text">
				2849
				2850	<h5>Syntax:</h5>
				2851
				2852	<pre>
Dan Gohman	bcc3c50	2008-05-12 23:38:42 +0000	[diff] [blame]	2853	<result> = insertelement <n x <ty>> <val>, <ty> <elt>, i32 <idx> <i>; yields <n x <ty>></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2854	</pre>
				2855
				2856	<h5>Overview:</h5>
				2857
				2858	<p>
				2859	The '<tt>insertelement</tt>' instruction inserts a scalar
				2860	element into a vector at a specified index.
				2861	</p>
				2862
				2863
				2864	<h5>Arguments:</h5>
				2865
				2866	<p>
				2867	The first operand of an '<tt>insertelement</tt>' instruction is a
				2868	value of <a href="#t_vector">vector</a> type. The second operand is a
				2869	scalar value whose type must equal the element type of the first
				2870	operand. The third operand is an index indicating the position at
				2871	which to insert the value. The index may be a variable.</p>
				2872
				2873	<h5>Semantics:</h5>
				2874
				2875	<p>
				2876	The result is a vector of the same type as <tt>val</tt>. Its
				2877	element values are those of <tt>val</tt> except at position
				2878	<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
				2879	exceeds the length of <tt>val</tt>, the results are undefined.
				2880	</p>
				2881
				2882	<h5>Example:</h5>
				2883
				2884	<pre>
				2885	%result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
				2886	</pre>
				2887	</div>
				2888
				2889	<!-- _______________________________________________________________________ -->
				2890	<div class="doc_subsubsection">
				2891	<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
				2892	</div>
				2893
				2894	<div class="doc_text">
				2895
				2896	<h5>Syntax:</h5>
				2897
				2898	<pre>
				2899	<result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x i32> <mask> <i>; yields <n x <ty>></i>
				2900	</pre>
				2901
				2902	<h5>Overview:</h5>
				2903
				2904	<p>
				2905	The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
				2906	from two input vectors, returning a vector of the same type.
				2907	</p>
				2908
				2909	<h5>Arguments:</h5>
				2910
				2911	<p>
				2912	The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
				2913	with types that match each other and types that match the result of the
				2914	instruction. The third argument is a shuffle mask, which has the same number
				2915	of elements as the other vector type, but whose element type is always 'i32'.
				2916	</p>
				2917
				2918	<p>
				2919	The shuffle mask operand is required to be a constant vector with either
				2920	constant integer or undef values.
				2921	</p>
				2922
				2923	<h5>Semantics:</h5>
				2924
				2925	<p>
				2926	The elements of the two input vectors are numbered from left to right across
				2927	both of the vectors. The shuffle mask operand specifies, for each element of
				2928	the result vector, which element of the two input registers the result element
				2929	gets. The element selector may be undef (meaning "don't care") and the second
				2930	operand may be undef if performing a shuffle from only one vector.
				2931	</p>
				2932
				2933	<h5>Example:</h5>
				2934
				2935	<pre>
				2936	%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
				2937	<4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
				2938	%result = shufflevector <4 x i32> %v1, <4 x i32> undef,
				2939	<4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
				2940	</pre>
				2941	</div>
				2942
				2943
				2944	<!-- ======================================================================= -->
				2945	<div class="doc_subsection">
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2946	<a name="aggregateops">Aggregate Operations</a>
				2947	</div>
				2948
				2949	<div class="doc_text">
				2950
				2951	<p>LLVM supports several instructions for working with aggregate values.
				2952	</p>
				2953
				2954	</div>
				2955
				2956	<!-- _______________________________________________________________________ -->
				2957	<div class="doc_subsubsection">
				2958	<a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
				2959	</div>
				2960
				2961	<div class="doc_text">
				2962
				2963	<h5>Syntax:</h5>
				2964
				2965	<pre>
				2966	<result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
				2967	</pre>
				2968
				2969	<h5>Overview:</h5>
				2970
				2971	<p>
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	2972	The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
				2973	or array element from an aggregate value.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2974	</p>
				2975
				2976
				2977	<h5>Arguments:</h5>
				2978
				2979	<p>
				2980	The first operand of an '<tt>extractvalue</tt>' instruction is a
				2981	value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	2982	type. The operands are constant indices to specify which value to extract
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2983	in a similar manner as indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2984	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				2985	</p>
				2986
				2987	<h5>Semantics:</h5>
				2988
				2989	<p>
				2990	The result is the value at the position in the aggregate specified by
				2991	the index operands.
				2992	</p>
				2993
				2994	<h5>Example:</h5>
				2995
				2996	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2997	%result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2998	</pre>
				2999	</div>
				3000
				3001
				3002	<!-- _______________________________________________________________________ -->
				3003	<div class="doc_subsubsection">
				3004	<a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
				3005	</div>
				3006
				3007	<div class="doc_text">
				3008
				3009	<h5>Syntax:</h5>
				3010
				3011	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3012	<result> = insertvalue <aggregate type> <val>, <ty> <val>, <idx> <i>; yields <n x <ty>></i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3013	</pre>
				3014
				3015	<h5>Overview:</h5>
				3016
				3017	<p>
				3018	The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3019	into a struct field or array element in an aggregate.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3020	</p>
				3021
				3022
				3023	<h5>Arguments:</h5>
				3024
				3025	<p>
				3026	The first operand of an '<tt>insertvalue</tt>' instruction is a
				3027	value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
				3028	The second operand is a first-class value to insert.
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	3029	The following operands are constant indices
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3030	indicating the position at which to insert the value in a similar manner as
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3031	indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3032	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				3033	The value to insert must have the same type as the value identified
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3034	by the indices.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3035
				3036	<h5>Semantics:</h5>
				3037
				3038	<p>
				3039	The result is an aggregate of the same type as <tt>val</tt>. Its
				3040	value is that of <tt>val</tt> except that the value at the position
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3041	specified by the indices is that of <tt>elt</tt>.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3042	</p>
				3043
				3044	<h5>Example:</h5>
				3045
				3046	<pre>
Dan Gohman	b1aab4e	2008-06-23 15:26:37 +0000	[diff] [blame]	3047	%result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3048	</pre>
				3049	</div>
				3050
				3051
				3052	<!-- ======================================================================= -->
				3053	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3054	<a name="memoryops">Memory Access and Addressing Operations</a>
				3055	</div>
				3056
				3057	<div class="doc_text">
				3058
				3059	<p>A key design point of an SSA-based representation is how it
				3060	represents memory. In LLVM, no memory locations are in SSA form, which
				3061	makes things very simple. This section describes how to read, write,
				3062	allocate, and free memory in LLVM.</p>
				3063
				3064	</div>
				3065
				3066	<!-- _______________________________________________________________________ -->
				3067	<div class="doc_subsubsection">
				3068	<a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
				3069	</div>
				3070
				3071	<div class="doc_text">
				3072
				3073	<h5>Syntax:</h5>
				3074
				3075	<pre>
				3076	<result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3077	</pre>
				3078
				3079	<h5>Overview:</h5>
				3080
				3081	<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3082	heap and returns a pointer to it. The object is always allocated in the generic
				3083	address space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3084
				3085	<h5>Arguments:</h5>
				3086
				3087	<p>The '<tt>malloc</tt>' instruction allocates
				3088	<tt>sizeof(<type>)*NumElements</tt>
				3089	bytes of memory from the operating system and returns a pointer of the
				3090	appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3091	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3092	If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3093	be aligned to at least that boundary. If not specified, or if zero, the target can
				3094	choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3095
				3096	<p>'<tt>type</tt>' must be a sized type.</p>
				3097
				3098	<h5>Semantics:</h5>
				3099
				3100	<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3101	a pointer is returned. The result of a zero byte allocattion is undefined. The
				3102	result is null if there is insufficient memory available.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3103
				3104	<h5>Example:</h5>
				3105
				3106	<pre>
				3107	%array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
				3108
				3109	%size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
				3110	%array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
				3111	%array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
				3112	%array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
				3113	%array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
				3114	</pre>
				3115	</div>
				3116
				3117	<!-- _______________________________________________________________________ -->
				3118	<div class="doc_subsubsection">
				3119	<a name="i_free">'<tt>free</tt>' Instruction</a>
				3120	</div>
				3121
				3122	<div class="doc_text">
				3123
				3124	<h5>Syntax:</h5>
				3125
				3126	<pre>
				3127	free <type> <value> <i>; yields {void}</i>
				3128	</pre>
				3129
				3130	<h5>Overview:</h5>
				3131
				3132	<p>The '<tt>free</tt>' instruction returns memory back to the unused
				3133	memory heap to be reallocated in the future.</p>
				3134
				3135	<h5>Arguments:</h5>
				3136
				3137	<p>'<tt>value</tt>' shall be a pointer value that points to a value
				3138	that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
				3139	instruction.</p>
				3140
				3141	<h5>Semantics:</h5>
				3142
				3143	<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner	329d653	2008-04-19 22:41:32 +0000	[diff] [blame]	3144	after this instruction executes. If the pointer is null, the operation
				3145	is a noop.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3146
				3147	<h5>Example:</h5>
				3148
				3149	<pre>
				3150	%array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
				3151	free [4 x i8]* %array
				3152	</pre>
				3153	</div>
				3154
				3155	<!-- _______________________________________________________________________ -->
				3156	<div class="doc_subsubsection">
				3157	<a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
				3158	</div>
				3159
				3160	<div class="doc_text">
				3161
				3162	<h5>Syntax:</h5>
				3163
				3164	<pre>
				3165	<result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3166	</pre>
				3167
				3168	<h5>Overview:</h5>
				3169
				3170	<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
				3171	currently executing function, to be automatically released when this function
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3172	returns to its caller. The object is always allocated in the generic address
				3173	space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3174
				3175	<h5>Arguments:</h5>
				3176
				3177	<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
				3178	bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3179	appropriate type to the program. If "NumElements" is specified, it is the
				3180	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3181	If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3182	to be aligned to at least that boundary. If not specified, or if zero, the target
				3183	can choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3184
				3185	<p>'<tt>type</tt>' may be any sized type.</p>
				3186
				3187	<h5>Semantics:</h5>
				3188
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3189	<p>Memory is allocated; a pointer is returned. The operation is undefiend if
				3190	there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3191	memory is automatically released when the function returns. The '<tt>alloca</tt>'
				3192	instruction is commonly used to represent automatic variables that must
				3193	have an address available. When the function returns (either with the <tt><a
				3194	href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3195	instructions), the memory is reclaimed. Allocating zero bytes
				3196	is legal, but the result is undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3197
				3198	<h5>Example:</h5>
				3199
				3200	<pre>
				3201	%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
				3202	%ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
				3203	%ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
				3204	%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
				3205	</pre>
				3206	</div>
				3207
				3208	<!-- _______________________________________________________________________ -->
				3209	<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
				3210	Instruction</a> </div>
				3211	<div class="doc_text">
				3212	<h5>Syntax:</h5>
				3213	<pre> <result> = load <ty>* <pointer>[, align <alignment>]<br> <result> = volatile load <ty>* <pointer>[, align <alignment>]<br></pre>
				3214	<h5>Overview:</h5>
				3215	<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
				3216	<h5>Arguments:</h5>
				3217	<p>The argument to the '<tt>load</tt>' instruction specifies the memory
				3218	address from which to load. The pointer must point to a <a
				3219	href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
				3220	marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
				3221	the number or order of execution of this <tt>load</tt> with other
				3222	volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
				3223	instructions. </p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3224	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3225	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3226	(that is, the alignment of the memory address). A value of 0 or an
				3227	omitted "align" argument means that the operation has the preferential
				3228	alignment for the target. It is the responsibility of the code emitter
				3229	to ensure that the alignment information is correct. Overestimating
				3230	the alignment results in an undefined behavior. Underestimating the
				3231	alignment may produce less efficient code. An alignment of 1 is always
				3232	safe.
				3233	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3234	<h5>Semantics:</h5>
				3235	<p>The location of memory pointed to is loaded.</p>
				3236	<h5>Examples:</h5>
				3237	<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
				3238	<a
				3239	href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
				3240	%val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
				3241	</pre>
				3242	</div>
				3243	<!-- _______________________________________________________________________ -->
				3244	<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
				3245	Instruction</a> </div>
				3246	<div class="doc_text">
				3247	<h5>Syntax:</h5>
				3248	<pre> store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3249	volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3250	</pre>
				3251	<h5>Overview:</h5>
				3252	<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
				3253	<h5>Arguments:</h5>
				3254	<p>There are two arguments to the '<tt>store</tt>' instruction: a value
				3255	to store and an address at which to store it. The type of the '<tt><pointer></tt>'
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3256	operand must be a pointer to the <a href="#t_firstclass">first class</a> type
				3257	of the '<tt><value></tt>'
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3258	operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
				3259	optimizer is not allowed to modify the number or order of execution of
				3260	this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
				3261	href="#i_store">store</a></tt> instructions.</p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3262	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3263	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3264	(that is, the alignment of the memory address). A value of 0 or an
				3265	omitted "align" argument means that the operation has the preferential
				3266	alignment for the target. It is the responsibility of the code emitter
				3267	to ensure that the alignment information is correct. Overestimating
				3268	the alignment results in an undefined behavior. Underestimating the
				3269	alignment may produce less efficient code. An alignment of 1 is always
				3270	safe.
				3271	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3272	<h5>Semantics:</h5>
				3273	<p>The contents of memory are updated to contain '<tt><value></tt>'
				3274	at the location specified by the '<tt><pointer></tt>' operand.</p>
				3275	<h5>Example:</h5>
				3276	<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling	63ffa14	2007-10-22 05:10:05 +0000	[diff] [blame]	3277	store i32 3, i32* %ptr <i>; yields {void}</i>
				3278	%val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3279	</pre>
				3280	</div>
				3281
				3282	<!-- _______________________________________________________________________ -->
				3283	<div class="doc_subsubsection">
				3284	<a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
				3285	</div>
				3286
				3287	<div class="doc_text">
				3288	<h5>Syntax:</h5>
				3289	<pre>
				3290	<result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}*
				3291	</pre>
				3292
				3293	<h5>Overview:</h5>
				3294
				3295	<p>
				3296	The '<tt>getelementptr</tt>' instruction is used to get the address of a
				3297	subelement of an aggregate data structure.</p>
				3298
				3299	<h5>Arguments:</h5>
				3300
				3301	<p>This instruction takes a list of integer operands that indicate what
				3302	elements of the aggregate object to index to. The actual types of the arguments
				3303	provided depend on the type of the first pointer argument. The
				3304	'<tt>getelementptr</tt>' instruction is used to index down through the type
				3305	levels of a structure or to a specific index in an array. When indexing into a
				3306	structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	3307	into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
				3308	values will be sign extended to 64-bits if required.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3309
				3310	<p>For example, let's consider a C code fragment and how it gets
				3311	compiled to LLVM:</p>
				3312
				3313	<div class="doc_code">
				3314	<pre>
				3315	struct RT {
				3316	char A;
				3317	int B[10][20];
				3318	char C;
				3319	};
				3320	struct ST {
				3321	int X;
				3322	double Y;
				3323	struct RT Z;
				3324	};
				3325
				3326	int foo(struct ST s) {
				3327	return &s[1].Z.B[5][13];
				3328	}
				3329	</pre>
				3330	</div>
				3331
				3332	<p>The LLVM code generated by the GCC frontend is:</p>
				3333
				3334	<div class="doc_code">
				3335	<pre>
				3336	%RT = type { i8 , [10 x [20 x i32]], i8 }
				3337	%ST = type { i32, double, %RT }
				3338
				3339	define i32* %foo(%ST* %s) {
				3340	entry:
				3341	%reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
				3342	ret i32* %reg
				3343	}
				3344	</pre>
				3345	</div>
				3346
				3347	<h5>Semantics:</h5>
				3348
				3349	<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
				3350	on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
				3351	and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
				3352	<a href="#t_integer">integer</a> type but the value will always be sign extended
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3353	to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
				3354	structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3355
				3356	<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
				3357	type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
				3358	}</tt>' type, a structure. The second index indexes into the third element of
				3359	the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
				3360	i8 }</tt>' type, another structure. The third index indexes into the second
				3361	element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
				3362	array. The two dimensions of the array are subscripted into, yielding an
				3363	'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
				3364	to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
				3365
				3366	<p>Note that it is perfectly legal to index partially through a
				3367	structure, returning a pointer to an inner element. Because of this,
				3368	the LLVM code for the given testcase is equivalent to:</p>
				3369
				3370	<pre>
				3371	define i32* %foo(%ST* %s) {
				3372	%t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
				3373	%t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
				3374	%t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
				3375	%t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
				3376	%t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
				3377	ret i32* %t5
				3378	}
				3379	</pre>
				3380
				3381	<p>Note that it is undefined to access an array out of bounds: array and
				3382	pointer indexes must always be within the defined bounds of the array type.
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	3383	The one exception for this rule is zero length arrays. These arrays are
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3384	defined to be accessible as variable length arrays, which requires access
				3385	beyond the zero'th element.</p>
				3386
				3387	<p>The getelementptr instruction is often confusing. For some more insight
				3388	into how it works, see <a href="GetElementPtr.html">the getelementptr
				3389	FAQ</a>.</p>
				3390
				3391	<h5>Example:</h5>
				3392
				3393	<pre>
				3394	<i>; yields [12 x i8]*:aptr</i>
				3395	%aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
				3396	</pre>
				3397	</div>
				3398
				3399	<!-- ======================================================================= -->
				3400	<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
				3401	</div>
				3402	<div class="doc_text">
				3403	<p>The instructions in this category are the conversion instructions (casting)
				3404	which all take a single operand and a type. They perform various bit conversions
				3405	on the operand.</p>
				3406	</div>
				3407
				3408	<!-- _______________________________________________________________________ -->
				3409	<div class="doc_subsubsection">
				3410	<a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
				3411	</div>
				3412	<div class="doc_text">
				3413
				3414	<h5>Syntax:</h5>
				3415	<pre>
				3416	<result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3417	</pre>
				3418
				3419	<h5>Overview:</h5>
				3420	<p>
				3421	The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
				3422	</p>
				3423
				3424	<h5>Arguments:</h5>
				3425	<p>
				3426	The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
				3427	be an <a href="#t_integer">integer</a> type, and a type that specifies the size
				3428	and type of the result, which must be an <a href="#t_integer">integer</a>
				3429	type. The bit size of <tt>value</tt> must be larger than the bit size of
				3430	<tt>ty2</tt>. Equal sized types are not allowed.</p>
				3431
				3432	<h5>Semantics:</h5>
				3433	<p>
				3434	The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
				3435	and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
				3436	larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
				3437	It will always truncate bits.</p>
				3438
				3439	<h5>Example:</h5>
				3440	<pre>
				3441	%X = trunc i32 257 to i8 <i>; yields i8:1</i>
				3442	%Y = trunc i32 123 to i1 <i>; yields i1:true</i>
				3443	%Y = trunc i32 122 to i1 <i>; yields i1:false</i>
				3444	</pre>
				3445	</div>
				3446
				3447	<!-- _______________________________________________________________________ -->
				3448	<div class="doc_subsubsection">
				3449	<a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
				3450	</div>
				3451	<div class="doc_text">
				3452
				3453	<h5>Syntax:</h5>
				3454	<pre>
				3455	<result> = zext <ty> <value> to <ty2> <i>; yields ty2</i>
				3456	</pre>
				3457
				3458	<h5>Overview:</h5>
				3459	<p>The '<tt>zext</tt>' instruction zero extends its operand to type
				3460	<tt>ty2</tt>.</p>
				3461
				3462
				3463	<h5>Arguments:</h5>
				3464	<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
				3465	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3466	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3467	<tt>value</tt> must be smaller than the bit size of the destination type,
				3468	<tt>ty2</tt>.</p>
				3469
				3470	<h5>Semantics:</h5>
				3471	<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
				3472	bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
				3473
				3474	<p>When zero extending from i1, the result will always be either 0 or 1.</p>
				3475
				3476	<h5>Example:</h5>
				3477	<pre>
				3478	%X = zext i32 257 to i64 <i>; yields i64:257</i>
				3479	%Y = zext i1 true to i32 <i>; yields i32:1</i>
				3480	</pre>
				3481	</div>
				3482
				3483	<!-- _______________________________________________________________________ -->
				3484	<div class="doc_subsubsection">
				3485	<a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
				3486	</div>
				3487	<div class="doc_text">
				3488
				3489	<h5>Syntax:</h5>
				3490	<pre>
				3491	<result> = sext <ty> <value> to <ty2> <i>; yields ty2</i>
				3492	</pre>
				3493
				3494	<h5>Overview:</h5>
				3495	<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
				3496
				3497	<h5>Arguments:</h5>
				3498	<p>
				3499	The '<tt>sext</tt>' instruction takes a value to cast, which must be of
				3500	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3501	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3502	<tt>value</tt> must be smaller than the bit size of the destination type,
				3503	<tt>ty2</tt>.</p>
				3504
				3505	<h5>Semantics:</h5>
				3506	<p>
				3507	The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
				3508	bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
				3509	the type <tt>ty2</tt>.</p>
				3510
				3511	<p>When sign extending from i1, the extension always results in -1 or 0.</p>
				3512
				3513	<h5>Example:</h5>
				3514	<pre>
				3515	%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
				3516	%Y = sext i1 true to i32 <i>; yields i32:-1</i>
				3517	</pre>
				3518	</div>
				3519
				3520	<!-- _______________________________________________________________________ -->
				3521	<div class="doc_subsubsection">
				3522	<a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
				3523	</div>
				3524
				3525	<div class="doc_text">
				3526
				3527	<h5>Syntax:</h5>
				3528
				3529	<pre>
				3530	<result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3531	</pre>
				3532
				3533	<h5>Overview:</h5>
				3534	<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
				3535	<tt>ty2</tt>.</p>
				3536
				3537
				3538	<h5>Arguments:</h5>
				3539	<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
				3540	point</a> value to cast and a <a href="#t_floating">floating point</a> type to
				3541	cast it to. The size of <tt>value</tt> must be larger than the size of
				3542	<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
				3543	<i>no-op cast</i>.</p>
				3544
				3545	<h5>Semantics:</h5>
				3546	<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
				3547	<a href="#t_floating">floating point</a> type to a smaller
				3548	<a href="#t_floating">floating point</a> type. If the value cannot fit within
				3549	the destination type, <tt>ty2</tt>, then the results are undefined.</p>
				3550
				3551	<h5>Example:</h5>
				3552	<pre>
				3553	%X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
				3554	%Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
				3555	</pre>
				3556	</div>
				3557
				3558	<!-- _______________________________________________________________________ -->
				3559	<div class="doc_subsubsection">
				3560	<a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
				3561	</div>
				3562	<div class="doc_text">
				3563
				3564	<h5>Syntax:</h5>
				3565	<pre>
				3566	<result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i>
				3567	</pre>
				3568
				3569	<h5>Overview:</h5>
				3570	<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
				3571	floating point value.</p>
				3572
				3573	<h5>Arguments:</h5>
				3574	<p>The '<tt>fpext</tt>' instruction takes a
				3575	<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
				3576	and a <a href="#t_floating">floating point</a> type to cast it to. The source
				3577	type must be smaller than the destination type.</p>
				3578
				3579	<h5>Semantics:</h5>
				3580	<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
				3581	<a href="#t_floating">floating point</a> type to a larger
				3582	<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
				3583	used to make a <i>no-op cast</i> because it always changes bits. Use
				3584	<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
				3585
				3586	<h5>Example:</h5>
				3587	<pre>
				3588	%X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
				3589	%Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
				3590	</pre>
				3591	</div>
				3592
				3593	<!-- _______________________________________________________________________ -->
				3594	<div class="doc_subsubsection">
				3595	<a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
				3596	</div>
				3597	<div class="doc_text">
				3598
				3599	<h5>Syntax:</h5>
				3600	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3601	<result> = fptoui <ty> <value> to <ty2> <i>; yields ty2</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3602	</pre>
				3603
				3604	<h5>Overview:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3605	<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3606	unsigned integer equivalent of type <tt>ty2</tt>.
				3607	</p>
				3608
				3609	<h5>Arguments:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3610	<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3611	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3612	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3613	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3614	vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3615
				3616	<h5>Semantics:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3617	<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3618	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3619	towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
				3620	the results are undefined.</p>
				3621
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3622	<h5>Example:</h5>
				3623	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3624	%X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3625	%Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3626	%X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3627	</pre>
				3628	</div>
				3629
				3630	<!-- _______________________________________________________________________ -->
				3631	<div class="doc_subsubsection">
				3632	<a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
				3633	</div>
				3634	<div class="doc_text">
				3635
				3636	<h5>Syntax:</h5>
				3637	<pre>
				3638	<result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i>
				3639	</pre>
				3640
				3641	<h5>Overview:</h5>
				3642	<p>The '<tt>fptosi</tt>' instruction converts
				3643	<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
				3644	</p>
				3645
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3646	<h5>Arguments:</h5>
				3647	<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3648	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3649	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3650	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3651	vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3652
				3653	<h5>Semantics:</h5>
				3654	<p>The '<tt>fptosi</tt>' instruction converts its
				3655	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3656	towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
				3657	the results are undefined.</p>
				3658
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3659	<h5>Example:</h5>
				3660	<pre>
				3661	%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3662	%Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3663	%X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
				3664	</pre>
				3665	</div>
				3666
				3667	<!-- _______________________________________________________________________ -->
				3668	<div class="doc_subsubsection">
				3669	<a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
				3670	</div>
				3671	<div class="doc_text">
				3672
				3673	<h5>Syntax:</h5>
				3674	<pre>
				3675	<result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3676	</pre>
				3677
				3678	<h5>Overview:</h5>
				3679	<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
				3680	integer and converts that value to the <tt>ty2</tt> type.</p>
				3681
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3682	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3683	<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
				3684	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3685	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3686	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3687	floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3688
				3689	<h5>Semantics:</h5>
				3690	<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
				3691	integer quantity and converts it to the corresponding floating point value. If
				3692	the value cannot fit in the floating point value, the results are undefined.</p>
				3693
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3694	<h5>Example:</h5>
				3695	<pre>
				3696	%X = uitofp i32 257 to float <i>; yields float:257.0</i>
				3697	%Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
				3698	</pre>
				3699	</div>
				3700
				3701	<!-- _______________________________________________________________________ -->
				3702	<div class="doc_subsubsection">
				3703	<a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
				3704	</div>
				3705	<div class="doc_text">
				3706
				3707	<h5>Syntax:</h5>
				3708	<pre>
				3709	<result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3710	</pre>
				3711
				3712	<h5>Overview:</h5>
				3713	<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
				3714	integer and converts that value to the <tt>ty2</tt> type.</p>
				3715
				3716	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3717	<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
				3718	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3719	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3720	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3721	floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3722
				3723	<h5>Semantics:</h5>
				3724	<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
				3725	integer quantity and converts it to the corresponding floating point value. If
				3726	the value cannot fit in the floating point value, the results are undefined.</p>
				3727
				3728	<h5>Example:</h5>
				3729	<pre>
				3730	%X = sitofp i32 257 to float <i>; yields float:257.0</i>
				3731	%Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
				3732	</pre>
				3733	</div>
				3734
				3735	<!-- _______________________________________________________________________ -->
				3736	<div class="doc_subsubsection">
				3737	<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
				3738	</div>
				3739	<div class="doc_text">
				3740
				3741	<h5>Syntax:</h5>
				3742	<pre>
				3743	<result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i>
				3744	</pre>
				3745
				3746	<h5>Overview:</h5>
				3747	<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
				3748	the integer type <tt>ty2</tt>.</p>
				3749
				3750	<h5>Arguments:</h5>
				3751	<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
				3752	must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
				3753	<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
				3754
				3755	<h5>Semantics:</h5>
				3756	<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
				3757	<tt>ty2</tt> by interpreting the pointer value as an integer and either
				3758	truncating or zero extending that value to the size of the integer type. If
				3759	<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
				3760	<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
				3761	are the same size, then nothing is done (<i>no-op cast</i>) other than a type
				3762	change.</p>
				3763
				3764	<h5>Example:</h5>
				3765	<pre>
				3766	%X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
				3767	%Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
				3768	</pre>
				3769	</div>
				3770
				3771	<!-- _______________________________________________________________________ -->
				3772	<div class="doc_subsubsection">
				3773	<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
				3774	</div>
				3775	<div class="doc_text">
				3776
				3777	<h5>Syntax:</h5>
				3778	<pre>
				3779	<result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i>
				3780	</pre>
				3781
				3782	<h5>Overview:</h5>
				3783	<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
				3784	a pointer type, <tt>ty2</tt>.</p>
				3785
				3786	<h5>Arguments:</h5>
				3787	<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
				3788	value to cast, and a type to cast it to, which must be a
				3789	<a href="#t_pointer">pointer</a> type.
				3790
				3791	<h5>Semantics:</h5>
				3792	<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
				3793	<tt>ty2</tt> by applying either a zero extension or a truncation depending on
				3794	the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
				3795	size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
				3796	the size of a pointer then a zero extension is done. If they are the same size,
				3797	nothing is done (<i>no-op cast</i>).</p>
				3798
				3799	<h5>Example:</h5>
				3800	<pre>
				3801	%X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
				3802	%X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
				3803	%Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
				3804	</pre>
				3805	</div>
				3806
				3807	<!-- _______________________________________________________________________ -->
				3808	<div class="doc_subsubsection">
				3809	<a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
				3810	</div>
				3811	<div class="doc_text">
				3812
				3813	<h5>Syntax:</h5>
				3814	<pre>
				3815	<result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i>
				3816	</pre>
				3817
				3818	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3819
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3820	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3821	<tt>ty2</tt> without changing any bits.</p>
				3822
				3823	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3824
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3825	<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman	7305fa0	2008-09-08 16:45:59 +0000	[diff] [blame]	3826	a non-aggregate first class value, and a type to cast it to, which must also be
				3827	a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
				3828	<tt>value</tt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3829	and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3830	type is a pointer, the destination type must also be a pointer. This
				3831	instruction supports bitwise conversion of vectors to integers and to vectors
				3832	of other types (as long as they have the same size).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3833
				3834	<h5>Semantics:</h5>
				3835	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3836	<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
				3837	this conversion. The conversion is done as if the <tt>value</tt> had been
				3838	stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
				3839	converted to other pointer types with this instruction. To convert pointers to
				3840	other types, use the <a href="#i_inttoptr">inttoptr</a> or
				3841	<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
				3842
				3843	<h5>Example:</h5>
				3844	<pre>
				3845	%X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
				3846	%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
				3847	%Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
				3848	</pre>
				3849	</div>
				3850
				3851	<!-- ======================================================================= -->
				3852	<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
				3853	<div class="doc_text">
				3854	<p>The instructions in this category are the "miscellaneous"
				3855	instructions, which defy better classification.</p>
				3856	</div>
				3857
				3858	<!-- _______________________________________________________________________ -->
				3859	<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
				3860	</div>
				3861	<div class="doc_text">
				3862	<h5>Syntax:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3863	<pre> <result> = icmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1&gt}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3864	</pre>
				3865	<h5>Overview:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3866	<p>The '<tt>icmp</tt>' instruction returns a boolean value or
				3867	a vector of boolean values based on comparison
				3868	of its two integer, integer vector, or pointer operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3869	<h5>Arguments:</h5>
				3870	<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
				3871	the condition code indicating the kind of comparison to perform. It is not
				3872	a value, just a keyword. The possible condition code are:
				3873	<ol>
				3874	<li><tt>eq</tt>: equal</li>
				3875	<li><tt>ne</tt>: not equal </li>
				3876	<li><tt>ugt</tt>: unsigned greater than</li>
				3877	<li><tt>uge</tt>: unsigned greater or equal</li>
				3878	<li><tt>ult</tt>: unsigned less than</li>
				3879	<li><tt>ule</tt>: unsigned less or equal</li>
				3880	<li><tt>sgt</tt>: signed greater than</li>
				3881	<li><tt>sge</tt>: signed greater or equal</li>
				3882	<li><tt>slt</tt>: signed less than</li>
				3883	<li><tt>sle</tt>: signed less or equal</li>
				3884	</ol>
				3885	<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3886	<a href="#t_pointer">pointer</a>
				3887	or integer <a href="#t_vector">vector</a> typed.
				3888	They must also be identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3889	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3890	<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3891	the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3892	yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3893	<ol>
				3894	<li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
				3895	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3896	</li>
				3897	<li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
				3898	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3899	<li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3900	<tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3901	<li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3902	<tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3903	<li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3904	<tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3905	<li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3906	<tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3907	<li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3908	<tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3909	<li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3910	<tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3911	<li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3912	<tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3913	<li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3914	<tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3915	</ol>
				3916	<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
				3917	values are compared as if they were integers.</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3918	<p>If the operands are integer vectors, then they are compared
				3919	element by element. The result is an <tt>i1</tt> vector with
				3920	the same number of elements as the values being compared.
				3921	Otherwise, the result is an <tt>i1</tt>.
				3922	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3923
				3924	<h5>Example:</h5>
				3925	<pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
				3926	<result> = icmp ne float* %X, %X <i>; yields: result=false</i>
				3927	<result> = icmp ult i16 4, 5 <i>; yields: result=true</i>
				3928	<result> = icmp sgt i16 4, 5 <i>; yields: result=false</i>
				3929	<result> = icmp ule i16 -4, 5 <i>; yields: result=false</i>
				3930	<result> = icmp sge i16 4, 5 <i>; yields: result=false</i>
				3931	</pre>
				3932	</div>
				3933
				3934	<!-- _______________________________________________________________________ -->
				3935	<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
				3936	</div>
				3937	<div class="doc_text">
				3938	<h5>Syntax:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3939	<pre> <result> = fcmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1&gt}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3940	</pre>
				3941	<h5>Overview:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3942	<p>The '<tt>fcmp</tt>' instruction returns a boolean value
				3943	or vector of boolean values based on comparison
				3944	of its operands.
				3945	<p>
				3946	If the operands are floating point scalars, then the result
				3947	type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
				3948	</p>
				3949	<p>If the operands are floating point vectors, then the result type
				3950	is a vector of boolean with the same number of elements as the
				3951	operands being compared.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3952	<h5>Arguments:</h5>
				3953	<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
				3954	the condition code indicating the kind of comparison to perform. It is not
				3955	a value, just a keyword. The possible condition code are:
				3956	<ol>
				3957	<li><tt>false</tt>: no comparison, always returns false</li>
				3958	<li><tt>oeq</tt>: ordered and equal</li>
				3959	<li><tt>ogt</tt>: ordered and greater than </li>
				3960	<li><tt>oge</tt>: ordered and greater than or equal</li>
				3961	<li><tt>olt</tt>: ordered and less than </li>
				3962	<li><tt>ole</tt>: ordered and less than or equal</li>
				3963	<li><tt>one</tt>: ordered and not equal</li>
				3964	<li><tt>ord</tt>: ordered (no nans)</li>
				3965	<li><tt>ueq</tt>: unordered or equal</li>
				3966	<li><tt>ugt</tt>: unordered or greater than </li>
				3967	<li><tt>uge</tt>: unordered or greater than or equal</li>
				3968	<li><tt>ult</tt>: unordered or less than </li>
				3969	<li><tt>ule</tt>: unordered or less than or equal</li>
				3970	<li><tt>une</tt>: unordered or not equal</li>
				3971	<li><tt>uno</tt>: unordered (either nans)</li>
				3972	<li><tt>true</tt>: no comparison, always returns true</li>
				3973	</ol>
				3974	<p><i>Ordered</i> means that neither operand is a QNAN while
				3975	<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3976	<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
				3977	either a <a href="#t_floating">floating point</a> type
				3978	or a <a href="#t_vector">vector</a> of floating point type.
				3979	They must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3980	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3981	<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3982	according to the condition code given as <tt>cond</tt>.
				3983	If the operands are vectors, then the vectors are compared
				3984	element by element.
				3985	Each comparison performed
				3986	always yields an <a href="#t_primitive">i1</a> result, as follows:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3987	<ol>
				3988	<li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
				3989	<li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3990	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3991	<li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3992	<tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3993	<li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3994	<tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3995	<li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3996	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3997	<li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3998	<tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3999	<li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4000	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4001	<li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
				4002	<li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4003	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4004	<li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4005	<tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4006	<li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4007	<tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4008	<li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4009	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4010	<li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4011	<tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4012	<li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4013	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4014	<li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
				4015	<li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
				4016	</ol>
				4017
				4018	<h5>Example:</h5>
				4019	<pre> <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4020	<result> = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
				4021	<result> = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
				4022	<result> = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4023	</pre>
				4024	</div>
				4025
				4026	<!-- _______________________________________________________________________ -->
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4027	<div class="doc_subsubsection">
				4028	<a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
				4029	</div>
				4030	<div class="doc_text">
				4031	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4032	<pre> <result> = vicmp <cond> <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4033	</pre>
				4034	<h5>Overview:</h5>
				4035	<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
				4036	element-wise comparison of its two integer vector operands.</p>
				4037	<h5>Arguments:</h5>
				4038	<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
				4039	the condition code indicating the kind of comparison to perform. It is not
				4040	a value, just a keyword. The possible condition code are:
				4041	<ol>
				4042	<li><tt>eq</tt>: equal</li>
				4043	<li><tt>ne</tt>: not equal </li>
				4044	<li><tt>ugt</tt>: unsigned greater than</li>
				4045	<li><tt>uge</tt>: unsigned greater or equal</li>
				4046	<li><tt>ult</tt>: unsigned less than</li>
				4047	<li><tt>ule</tt>: unsigned less or equal</li>
				4048	<li><tt>sgt</tt>: signed greater than</li>
				4049	<li><tt>sge</tt>: signed greater or equal</li>
				4050	<li><tt>slt</tt>: signed less than</li>
				4051	<li><tt>sle</tt>: signed less or equal</li>
				4052	</ol>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4053	<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4054	<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
				4055	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4056	<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4057	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4058	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
				4059	identical type as the values being compared. The most significant bit in each
				4060	element is 1 if the element-wise comparison evaluates to true, and is 0
				4061	otherwise. All other bits of the result are undefined. The condition codes
				4062	are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
				4063	instruction</a>.
				4064
				4065	<h5>Example:</h5>
				4066	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4067	<result> = vicmp eq <2 x i32> < i32 4, i32 0>, < i32 5, i32 0> <i>; yields: result=<2 x i32> < i32 0, i32 -1 ></i>
				4068	<result> = vicmp ult <2 x i8 > < i8 1, i8 2>, < i8 2, i8 2 > <i>; yields: result=<2 x i8> < i8 -1, i8 0 ></i>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4069	</pre>
				4070	</div>
				4071
				4072	<!-- _______________________________________________________________________ -->
				4073	<div class="doc_subsubsection">
				4074	<a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
				4075	</div>
				4076	<div class="doc_text">
				4077	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4078	<pre> <result> = vfcmp <cond> <ty> <op1>, <op2></pre>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4079	<h5>Overview:</h5>
				4080	<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
				4081	element-wise comparison of its two floating point vector operands. The output
				4082	elements have the same width as the input elements.</p>
				4083	<h5>Arguments:</h5>
				4084	<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
				4085	the condition code indicating the kind of comparison to perform. It is not
				4086	a value, just a keyword. The possible condition code are:
				4087	<ol>
				4088	<li><tt>false</tt>: no comparison, always returns false</li>
				4089	<li><tt>oeq</tt>: ordered and equal</li>
				4090	<li><tt>ogt</tt>: ordered and greater than </li>
				4091	<li><tt>oge</tt>: ordered and greater than or equal</li>
				4092	<li><tt>olt</tt>: ordered and less than </li>
				4093	<li><tt>ole</tt>: ordered and less than or equal</li>
				4094	<li><tt>one</tt>: ordered and not equal</li>
				4095	<li><tt>ord</tt>: ordered (no nans)</li>
				4096	<li><tt>ueq</tt>: unordered or equal</li>
				4097	<li><tt>ugt</tt>: unordered or greater than </li>
				4098	<li><tt>uge</tt>: unordered or greater than or equal</li>
				4099	<li><tt>ult</tt>: unordered or less than </li>
				4100	<li><tt>ule</tt>: unordered or less than or equal</li>
				4101	<li><tt>une</tt>: unordered or not equal</li>
				4102	<li><tt>uno</tt>: unordered (either nans)</li>
				4103	<li><tt>true</tt>: no comparison, always returns true</li>
				4104	</ol>
				4105	<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
				4106	<a href="#t_floating">floating point</a> typed. They must also be identical
				4107	types.</p>
				4108	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4109	<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4110	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4111	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
				4112	an identical number of elements as the values being compared, and each element
				4113	having identical with to the width of the floating point elements. The most
				4114	significant bit in each element is 1 if the element-wise comparison evaluates to
				4115	true, and is 0 otherwise. All other bits of the result are undefined. The
				4116	condition codes are evaluated identically to the
				4117	<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
				4118
				4119	<h5>Example:</h5>
				4120	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4121	<result> = vfcmp oeq <2 x float> < float 4, float 0 >, < float 5, float 0 > <i>; yields: result=<2 x i32> < i32 0, i32 -1 ></i>
				4122	<result> = vfcmp ult <2 x double> < double 1, double 2 >, < double 2, double 2> <i>; yields: result=<2 x i64> < i64 -1, i64 0 ></i>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4123	</pre>
				4124	</div>
				4125
				4126	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4127	<div class="doc_subsubsection">
				4128	<a name="i_phi">'<tt>phi</tt>' Instruction</a>
				4129	</div>
				4130
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4131	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4132
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4133	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4134
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4135	<pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre>
				4136	<h5>Overview:</h5>
				4137	<p>The '<tt>phi</tt>' instruction is used to implement the φ node in
				4138	the SSA graph representing the function.</p>
				4139	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4140
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4141	<p>The type of the incoming values is specified with the first type
				4142	field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
				4143	as arguments, with one pair for each predecessor basic block of the
				4144	current block. Only values of <a href="#t_firstclass">first class</a>
				4145	type may be used as the value arguments to the PHI node. Only labels
				4146	may be used as the label arguments.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4147
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4148	<p>There must be no non-phi instructions between the start of a basic
				4149	block and the PHI instructions: i.e. PHI instructions must be first in
				4150	a basic block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4151
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4152	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4153
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4154	<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
				4155	specified by the pair corresponding to the predecessor basic block that executed
				4156	just prior to the current block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4157
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4158	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4159	<pre>
				4160	Loop: ; Infinite loop that counts from 0 on up...
				4161	%indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
				4162	%nextindvar = add i32 %indvar, 1
				4163	br label %Loop
				4164	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4165	</div>
				4166
				4167	<!-- _______________________________________________________________________ -->
				4168	<div class="doc_subsubsection">
				4169	<a name="i_select">'<tt>select</tt>' Instruction</a>
				4170	</div>
				4171
				4172	<div class="doc_text">
				4173
				4174	<h5>Syntax:</h5>
				4175
				4176	<pre>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4177	<result> = select <i>selty</i> <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
				4178
				4179	<i>selty</i> is either i1 or {<N x i1&gt}
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4180	</pre>
				4181
				4182	<h5>Overview:</h5>
				4183
				4184	<p>
				4185	The '<tt>select</tt>' instruction is used to choose one value based on a
				4186	condition, without branching.
				4187	</p>
				4188
				4189
				4190	<h5>Arguments:</h5>
				4191
				4192	<p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4193	The '<tt>select</tt>' instruction requires an 'i1' value or
				4194	a vector of 'i1' values indicating the
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4195	condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4196	type. If the val1/val2 are vectors and
				4197	the condition is a scalar, then entire vectors are selected, not
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4198	individual elements.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4199	</p>
				4200
				4201	<h5>Semantics:</h5>
				4202
				4203	<p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4204	If the condition is an i1 and it evaluates to 1, the instruction returns the first
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4205	value argument; otherwise, it returns the second value argument.
				4206	</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4207	<p>
				4208	If the condition is a vector of i1, then the value arguments must
				4209	be vectors of the same size, and the selection is done element
				4210	by element.
				4211	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4212
				4213	<h5>Example:</h5>
				4214
				4215	<pre>
				4216	%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
				4217	</pre>
				4218	</div>
				4219
				4220
				4221	<!-- _______________________________________________________________________ -->
				4222	<div class="doc_subsubsection">
				4223	<a name="i_call">'<tt>call</tt>' Instruction</a>
				4224	</div>
				4225
				4226	<div class="doc_text">
				4227
				4228	<h5>Syntax:</h5>
				4229	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4230	<result> = [tail] call [<a href="#callingconv">cconv</a>] <ty> [<fnty>*] <fnptrval>(<param list>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4231	</pre>
				4232
				4233	<h5>Overview:</h5>
				4234
				4235	<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
				4236
				4237	<h5>Arguments:</h5>
				4238
				4239	<p>This instruction requires several arguments:</p>
				4240
				4241	<ol>
				4242	<li>
				4243	<p>The optional "tail" marker indicates whether the callee function accesses
				4244	any allocas or varargs in the caller. If the "tail" marker is present, the
				4245	function call is eligible for tail call optimization. Note that calls may
				4246	be marked "tail" even if they do not occur before a <a
				4247	href="#i_ret"><tt>ret</tt></a> instruction.
				4248	</li>
				4249	<li>
				4250	<p>The optional "cconv" marker indicates which <a href="#callingconv">calling
				4251	convention</a> the call should use. If none is specified, the call defaults
				4252	to using C calling conventions.
				4253	</li>
				4254	<li>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4255	<p>'<tt>ty</tt>': the type of the call instruction itself which is also
				4256	the type of the return value. Functions that return no value are marked
				4257	<tt><a href="#t_void">void</a></tt>.</p>
				4258	</li>
				4259	<li>
				4260	<p>'<tt>fnty</tt>': shall be the signature of the pointer to function
				4261	value being invoked. The argument types must match the types implied by
				4262	this signature. This type can be omitted if the function is not varargs
				4263	and if the function type does not return a pointer to a function.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4264	</li>
				4265	<li>
				4266	<p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
				4267	be invoked. In most cases, this is a direct function invocation, but
				4268	indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
				4269	to function value.</p>
				4270	</li>
				4271	<li>
				4272	<p>'<tt>function args</tt>': argument list whose types match the
				4273	function signature argument types. All arguments must be of
				4274	<a href="#t_firstclass">first class</a> type. If the function signature
				4275	indicates the function accepts a variable number of arguments, the extra
				4276	arguments can be specified.</p>
				4277	</li>
				4278	</ol>
				4279
				4280	<h5>Semantics:</h5>
				4281
				4282	<p>The '<tt>call</tt>' instruction is used to cause control flow to
				4283	transfer to a specified function, with its incoming arguments bound to
				4284	the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
				4285	instruction in the called function, control flow continues with the
				4286	instruction after the function call, and the return value of the
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4287	function is bound to the result argument. If the callee returns multiple
				4288	values then the return values of the function are only accessible through
				4289	the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4290
				4291	<h5>Example:</h5>
				4292
				4293	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4294	%retval = call i32 @test(i32 %argc)
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4295	call i32 (i8 , ...) @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
				4296	%X = tail call i32 @foo() <i>; yields i32</i>
				4297	%Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
				4298	call void %foo(i8 97 signext)
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4299
				4300	%struct.A = type { i32, i8 }
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4301	%r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
				4302	%gr = getresult %struct.A %r, 0 <i>; yields i32</i>
				4303	%gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4304	</pre>
				4305
				4306	</div>
				4307
				4308	<!-- _______________________________________________________________________ -->
				4309	<div class="doc_subsubsection">
				4310	<a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
				4311	</div>
				4312
				4313	<div class="doc_text">
				4314
				4315	<h5>Syntax:</h5>
				4316
				4317	<pre>
				4318	<resultval> = va_arg <va_list*> <arglist>, <argty>
				4319	</pre>
				4320
				4321	<h5>Overview:</h5>
				4322
				4323	<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
				4324	the "variable argument" area of a function call. It is used to implement the
				4325	<tt>va_arg</tt> macro in C.</p>
				4326
				4327	<h5>Arguments:</h5>
				4328
				4329	<p>This instruction takes a <tt>va_list*</tt> value and the type of
				4330	the argument. It returns a value of the specified argument type and
				4331	increments the <tt>va_list</tt> to point to the next argument. The
				4332	actual type of <tt>va_list</tt> is target specific.</p>
				4333
				4334	<h5>Semantics:</h5>
				4335
				4336	<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
				4337	type from the specified <tt>va_list</tt> and causes the
				4338	<tt>va_list</tt> to point to the next argument. For more information,
				4339	see the variable argument handling <a href="#int_varargs">Intrinsic
				4340	Functions</a>.</p>
				4341
				4342	<p>It is legal for this instruction to be called in a function which does not
				4343	take a variable number of arguments, for example, the <tt>vfprintf</tt>
				4344	function.</p>
				4345
				4346	<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
				4347	href="#intrinsics">intrinsic function</a> because it takes a type as an
				4348	argument.</p>
				4349
				4350	<h5>Example:</h5>
				4351
				4352	<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
				4353
				4354	</div>
				4355
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4356	<!-- _______________________________________________________________________ -->
				4357	<div class="doc_subsubsection">
				4358	<a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
				4359	</div>
				4360
				4361	<div class="doc_text">
				4362
				4363	<h5>Syntax:</h5>
				4364	<pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4365	<resultval> = getresult <type> <retval>, <index>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4366	</pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4367
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4368	<h5>Overview:</h5>
				4369
				4370	<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4371	from a '<tt><a href="#i_call">call</a></tt>'
				4372	or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
				4373	results.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4374
				4375	<h5>Arguments:</h5>
				4376
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4377	<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattner	d8dd352	2008-04-23 04:06:52 +0000	[diff] [blame]	4378	first argument, or an undef value. The value must have <a
				4379	href="#t_struct">structure type</a>. The second argument is a constant
				4380	unsigned index value which must be in range for the number of values returned
				4381	by the call.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4382
				4383	<h5>Semantics:</h5>
				4384
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4385	<p>The '<tt>getresult</tt>' instruction extracts the element identified by
				4386	'<tt>index</tt>' from the aggregate value.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4387
				4388	<h5>Example:</h5>
				4389
				4390	<pre>
				4391	%struct.A = type { i32, i8 }
				4392
				4393	%r = call %struct.A @foo()
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4394	%gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
				4395	%gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4396	add i32 %gr, 42
				4397	add i8 %gr1, 41
				4398	</pre>
				4399
				4400	</div>
				4401
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4402	<!-- *********************************************************************** -->
				4403	<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
				4404	<!-- *********************************************************************** -->
				4405
				4406	<div class="doc_text">
				4407
				4408	<p>LLVM supports the notion of an "intrinsic function". These functions have
				4409	well known names and semantics and are required to follow certain restrictions.
				4410	Overall, these intrinsics represent an extension mechanism for the LLVM
				4411	language that does not require changing all of the transformations in LLVM when
				4412	adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
				4413
				4414	<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
				4415	prefix is reserved in LLVM for intrinsic names; thus, function names may not
				4416	begin with this prefix. Intrinsic functions must always be external functions:
				4417	you cannot define the body of intrinsic functions. Intrinsic functions may
				4418	only be used in call or invoke instructions: it is illegal to take the address
				4419	of an intrinsic function. Additionally, because intrinsic functions are part
				4420	of the LLVM language, it is required if any are added that they be documented
				4421	here.</p>
				4422
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4423	<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
				4424	a family of functions that perform the same operation but on different data
				4425	types. Because LLVM can represent over 8 million different integer types,
				4426	overloading is used commonly to allow an intrinsic function to operate on any
				4427	integer type. One or more of the argument types or the result type can be
				4428	overloaded to accept any integer type. Argument types may also be defined as
				4429	exactly matching a previous argument's type or the result type. This allows an
				4430	intrinsic function which accepts multiple arguments, but needs all of them to
				4431	be of the same type, to only be overloaded with respect to a single argument or
				4432	the result.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4433
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4434	<p>Overloaded intrinsics will have the names of its overloaded argument types
				4435	encoded into its function name, each preceded by a period. Only those types
				4436	which are overloaded result in a name suffix. Arguments whose type is matched
				4437	against another type do not. For example, the <tt>llvm.ctpop</tt> function can
				4438	take an integer of any width and returns an integer of exactly the same integer
				4439	width. This leads to a family of functions such as
				4440	<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
				4441	Only one type, the return type, is overloaded, and only one type suffix is
				4442	required. Because the argument's type is matched against the return type, it
				4443	does not require its own name suffix.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4444
				4445	<p>To learn how to add an intrinsic function, please see the
				4446	<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
				4447	</p>
				4448
				4449	</div>
				4450
				4451	<!-- ======================================================================= -->
				4452	<div class="doc_subsection">
				4453	<a name="int_varargs">Variable Argument Handling Intrinsics</a>
				4454	</div>
				4455
				4456	<div class="doc_text">
				4457
				4458	<p>Variable argument support is defined in LLVM with the <a
				4459	href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
				4460	intrinsic functions. These functions are related to the similarly
				4461	named macros defined in the <tt><stdarg.h></tt> header file.</p>
				4462
				4463	<p>All of these functions operate on arguments that use a
				4464	target-specific value type "<tt>va_list</tt>". The LLVM assembly
				4465	language reference manual does not define what this type is, so all
				4466	transformations should be prepared to handle these functions regardless of
				4467	the type used.</p>
				4468
				4469	<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
				4470	instruction and the variable argument handling intrinsic functions are
				4471	used.</p>
				4472
				4473	<div class="doc_code">
				4474	<pre>
				4475	define i32 @test(i32 %X, ...) {
				4476	; Initialize variable argument processing
				4477	%ap = alloca i8*
				4478	%ap2 = bitcast i8** %ap to i8*
				4479	call void @llvm.va_start(i8* %ap2)
				4480
				4481	; Read a single integer argument
				4482	%tmp = va_arg i8** %ap, i32
				4483
				4484	; Demonstrate usage of llvm.va_copy and llvm.va_end
				4485	%aq = alloca i8*
				4486	%aq2 = bitcast i8** %aq to i8*
				4487	call void @llvm.va_copy(i8* %aq2, i8* %ap2)
				4488	call void @llvm.va_end(i8* %aq2)
				4489
				4490	; Stop processing of arguments.
				4491	call void @llvm.va_end(i8* %ap2)
				4492	ret i32 %tmp
				4493	}
				4494
				4495	declare void @llvm.va_start(i8*)
				4496	declare void @llvm.va_copy(i8, i8)
				4497	declare void @llvm.va_end(i8*)
				4498	</pre>
				4499	</div>
				4500
				4501	</div>
				4502
				4503	<!-- _______________________________________________________________________ -->
				4504	<div class="doc_subsubsection">
				4505	<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
				4506	</div>
				4507
				4508
				4509	<div class="doc_text">
				4510	<h5>Syntax:</h5>
				4511	<pre> declare void %llvm.va_start(i8* <arglist>)<br></pre>
				4512	<h5>Overview:</h5>
				4513	<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
				4514	<tt>*<arglist></tt> for subsequent use by <tt><a
				4515	href="#i_va_arg">va_arg</a></tt>.</p>
				4516
				4517	<h5>Arguments:</h5>
				4518
				4519	<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
				4520
				4521	<h5>Semantics:</h5>
				4522
				4523	<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
				4524	macro available in C. In a target-dependent way, it initializes the
				4525	<tt>va_list</tt> element to which the argument points, so that the next call to
				4526	<tt>va_arg</tt> will produce the first variable argument passed to the function.
				4527	Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
				4528	last argument of the function as the compiler can figure that out.</p>
				4529
				4530	</div>
				4531
				4532	<!-- _______________________________________________________________________ -->
				4533	<div class="doc_subsubsection">
				4534	<a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
				4535	</div>
				4536
				4537	<div class="doc_text">
				4538	<h5>Syntax:</h5>
				4539	<pre> declare void @llvm.va_end(i8* <arglist>)<br></pre>
				4540	<h5>Overview:</h5>
				4541
				4542	<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
				4543	which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
				4544	or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
				4545
				4546	<h5>Arguments:</h5>
				4547
				4548	<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
				4549
				4550	<h5>Semantics:</h5>
				4551
				4552	<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
				4553	macro available in C. In a target-dependent way, it destroys the
				4554	<tt>va_list</tt> element to which the argument points. Calls to <a
				4555	href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
				4556	<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
				4557	<tt>llvm.va_end</tt>.</p>
				4558
				4559	</div>
				4560
				4561	<!-- _______________________________________________________________________ -->
				4562	<div class="doc_subsubsection">
				4563	<a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
				4564	</div>
				4565
				4566	<div class="doc_text">
				4567
				4568	<h5>Syntax:</h5>
				4569
				4570	<pre>
				4571	declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)
				4572	</pre>
				4573
				4574	<h5>Overview:</h5>
				4575
				4576	<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
				4577	from the source argument list to the destination argument list.</p>
				4578
				4579	<h5>Arguments:</h5>
				4580
				4581	<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
				4582	The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
				4583
				4584
				4585	<h5>Semantics:</h5>
				4586
				4587	<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
				4588	macro available in C. In a target-dependent way, it copies the source
				4589	<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
				4590	intrinsic is necessary because the <tt><a href="#int_va_start">
				4591	llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
				4592	example, memory allocation.</p>
				4593
				4594	</div>
				4595
				4596	<!-- ======================================================================= -->
				4597	<div class="doc_subsection">
				4598	<a name="int_gc">Accurate Garbage Collection Intrinsics</a>
				4599	</div>
				4600
				4601	<div class="doc_text">
				4602
				4603	<p>
				4604	LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	4605	Collection</a> (GC) requires the implementation and generation of these
				4606	intrinsics.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4607	These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
				4608	stack</a>, as well as garbage collector implementations that require <a
				4609	href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
				4610	Front-ends for type-safe garbage collected languages should generate these
				4611	intrinsics to make use of the LLVM garbage collectors. For more details, see <a
				4612	href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
				4613	</p>
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	4614
				4615	<p>The garbage collection intrinsics only operate on objects in the generic
				4616	address space (address space zero).</p>
				4617
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4618	</div>
				4619
				4620	<!-- _______________________________________________________________________ -->
				4621	<div class="doc_subsubsection">
				4622	<a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
				4623	</div>
				4624
				4625	<div class="doc_text">
				4626
				4627	<h5>Syntax:</h5>
				4628
				4629	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4630	declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4631	</pre>
				4632
				4633	<h5>Overview:</h5>
				4634
				4635	<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
				4636	the code generator, and allows some metadata to be associated with it.</p>
				4637
				4638	<h5>Arguments:</h5>
				4639
				4640	<p>The first argument specifies the address of a stack object that contains the
				4641	root pointer. The second pointer (which must be either a constant or a global
				4642	value address) contains the meta-data to be associated with the root.</p>
				4643
				4644	<h5>Semantics:</h5>
				4645
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	4646	<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4647	location. At compile-time, the code generator generates information to allow
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4648	the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
				4649	intrinsic may only be used in a function which <a href="#gc">specifies a GC
				4650	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4651
				4652	</div>
				4653
				4654
				4655	<!-- _______________________________________________________________________ -->
				4656	<div class="doc_subsubsection">
				4657	<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
				4658	</div>
				4659
				4660	<div class="doc_text">
				4661
				4662	<h5>Syntax:</h5>
				4663
				4664	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4665	declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4666	</pre>
				4667
				4668	<h5>Overview:</h5>
				4669
				4670	<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
				4671	locations, allowing garbage collector implementations that require read
				4672	barriers.</p>
				4673
				4674	<h5>Arguments:</h5>
				4675
				4676	<p>The second argument is the address to read from, which should be an address
				4677	allocated from the garbage collector. The first object is a pointer to the
				4678	start of the referenced object, if needed by the language runtime (otherwise
				4679	null).</p>
				4680
				4681	<h5>Semantics:</h5>
				4682
				4683	<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
				4684	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4685	garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
				4686	may only be used in a function which <a href="#gc">specifies a GC
				4687	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4688
				4689	</div>
				4690
				4691
				4692	<!-- _______________________________________________________________________ -->
				4693	<div class="doc_subsubsection">
				4694	<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
				4695	</div>
				4696
				4697	<div class="doc_text">
				4698
				4699	<h5>Syntax:</h5>
				4700
				4701	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4702	declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4703	</pre>
				4704
				4705	<h5>Overview:</h5>
				4706
				4707	<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
				4708	locations, allowing garbage collector implementations that require write
				4709	barriers (such as generational or reference counting collectors).</p>
				4710
				4711	<h5>Arguments:</h5>
				4712
				4713	<p>The first argument is the reference to store, the second is the start of the
				4714	object to store it to, and the third is the address of the field of Obj to
				4715	store to. If the runtime does not require a pointer to the object, Obj may be
				4716	null.</p>
				4717
				4718	<h5>Semantics:</h5>
				4719
				4720	<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
				4721	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4722	garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
				4723	may only be used in a function which <a href="#gc">specifies a GC
				4724	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4725
				4726	</div>
				4727
				4728
				4729
				4730	<!-- ======================================================================= -->
				4731	<div class="doc_subsection">
				4732	<a name="int_codegen">Code Generator Intrinsics</a>
				4733	</div>
				4734
				4735	<div class="doc_text">
				4736	<p>
				4737	These intrinsics are provided by LLVM to expose special features that may only
				4738	be implemented with code generator support.
				4739	</p>
				4740
				4741	</div>
				4742
				4743	<!-- _______________________________________________________________________ -->
				4744	<div class="doc_subsubsection">
				4745	<a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
				4746	</div>
				4747
				4748	<div class="doc_text">
				4749
				4750	<h5>Syntax:</h5>
				4751	<pre>
				4752	declare i8 *@llvm.returnaddress(i32 <level>)
				4753	</pre>
				4754
				4755	<h5>Overview:</h5>
				4756
				4757	<p>
				4758	The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
				4759	target-specific value indicating the return address of the current function
				4760	or one of its callers.
				4761	</p>
				4762
				4763	<h5>Arguments:</h5>
				4764
				4765	<p>
				4766	The argument to this intrinsic indicates which function to return the address
				4767	for. Zero indicates the calling function, one indicates its caller, etc. The
				4768	argument is <b>required</b> to be a constant integer value.
				4769	</p>
				4770
				4771	<h5>Semantics:</h5>
				4772
				4773	<p>
				4774	The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
				4775	the return address of the specified call frame, or zero if it cannot be
				4776	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4777	for arguments other than zero, so it should only be used for debugging purposes.
				4778	</p>
				4779
				4780	<p>
				4781	Note that calling this intrinsic does not prevent function inlining or other
				4782	aggressive transformations, so the value returned may not be that of the obvious
				4783	source-language caller.
				4784	</p>
				4785	</div>
				4786
				4787
				4788	<!-- _______________________________________________________________________ -->
				4789	<div class="doc_subsubsection">
				4790	<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
				4791	</div>
				4792
				4793	<div class="doc_text">
				4794
				4795	<h5>Syntax:</h5>
				4796	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4797	declare i8 *@llvm.frameaddress(i32 <level>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4798	</pre>
				4799
				4800	<h5>Overview:</h5>
				4801
				4802	<p>
				4803	The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
				4804	target-specific frame pointer value for the specified stack frame.
				4805	</p>
				4806
				4807	<h5>Arguments:</h5>
				4808
				4809	<p>
				4810	The argument to this intrinsic indicates which function to return the frame
				4811	pointer for. Zero indicates the calling function, one indicates its caller,
				4812	etc. The argument is <b>required</b> to be a constant integer value.
				4813	</p>
				4814
				4815	<h5>Semantics:</h5>
				4816
				4817	<p>
				4818	The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
				4819	the frame address of the specified call frame, or zero if it cannot be
				4820	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4821	for arguments other than zero, so it should only be used for debugging purposes.
				4822	</p>
				4823
				4824	<p>
				4825	Note that calling this intrinsic does not prevent function inlining or other
				4826	aggressive transformations, so the value returned may not be that of the obvious
				4827	source-language caller.
				4828	</p>
				4829	</div>
				4830
				4831	<!-- _______________________________________________________________________ -->
				4832	<div class="doc_subsubsection">
				4833	<a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
				4834	</div>
				4835
				4836	<div class="doc_text">
				4837
				4838	<h5>Syntax:</h5>
				4839	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4840	declare i8 *@llvm.stacksave()
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4841	</pre>
				4842
				4843	<h5>Overview:</h5>
				4844
				4845	<p>
				4846	The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
				4847	the function stack, for use with <a href="#int_stackrestore">
				4848	<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
				4849	features like scoped automatic variable sized arrays in C99.
				4850	</p>
				4851
				4852	<h5>Semantics:</h5>
				4853
				4854	<p>
				4855	This intrinsic returns a opaque pointer value that can be passed to <a
				4856	href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
				4857	<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
				4858	<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
				4859	state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
				4860	practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
				4861	that were allocated after the <tt>llvm.stacksave</tt> was executed.
				4862	</p>
				4863
				4864	</div>
				4865
				4866	<!-- _______________________________________________________________________ -->
				4867	<div class="doc_subsubsection">
				4868	<a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
				4869	</div>
				4870
				4871	<div class="doc_text">
				4872
				4873	<h5>Syntax:</h5>
				4874	<pre>
				4875	declare void @llvm.stackrestore(i8 * %ptr)
				4876	</pre>
				4877
				4878	<h5>Overview:</h5>
				4879
				4880	<p>
				4881	The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
				4882	the function stack to the state it was in when the corresponding <a
				4883	href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
				4884	useful for implementing language features like scoped automatic variable sized
				4885	arrays in C99.
				4886	</p>
				4887
				4888	<h5>Semantics:</h5>
				4889
				4890	<p>
				4891	See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
				4892	</p>
				4893
				4894	</div>
				4895
				4896
				4897	<!-- _______________________________________________________________________ -->
				4898	<div class="doc_subsubsection">
				4899	<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
				4900	</div>
				4901
				4902	<div class="doc_text">
				4903
				4904	<h5>Syntax:</h5>
				4905	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4906	declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4907	</pre>
				4908
				4909	<h5>Overview:</h5>
				4910
				4911
				4912	<p>
				4913	The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
				4914	a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
				4915	no
				4916	effect on the behavior of the program but can change its performance
				4917	characteristics.
				4918	</p>
				4919
				4920	<h5>Arguments:</h5>
				4921
				4922	<p>
				4923	<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
				4924	determining if the fetch should be for a read (0) or write (1), and
				4925	<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
				4926	locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
				4927	<tt>locality</tt> arguments must be constant integers.
				4928	</p>
				4929
				4930	<h5>Semantics:</h5>
				4931
				4932	<p>
				4933	This intrinsic does not modify the behavior of the program. In particular,
				4934	prefetches cannot trap and do not produce a value. On targets that support this
				4935	intrinsic, the prefetch can provide hints to the processor cache for better
				4936	performance.
				4937	</p>
				4938
				4939	</div>
				4940
				4941	<!-- _______________________________________________________________________ -->
				4942	<div class="doc_subsubsection">
				4943	<a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
				4944	</div>
				4945
				4946	<div class="doc_text">
				4947
				4948	<h5>Syntax:</h5>
				4949	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4950	declare void @llvm.pcmarker(i32 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4951	</pre>
				4952
				4953	<h5>Overview:</h5>
				4954
				4955
				4956	<p>
				4957	The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	4958	(PC) in a region of
				4959	code to simulators and other tools. The method is target specific, but it is
				4960	expected that the marker will use exported symbols to transmit the PC of the
				4961	marker.
				4962	The marker makes no guarantees that it will remain with any specific instruction
				4963	after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4964	optimizations. The intended use is to be inserted after optimizations to allow
				4965	correlations of simulation runs.
				4966	</p>
				4967
				4968	<h5>Arguments:</h5>
				4969
				4970	<p>
				4971	<tt>id</tt> is a numerical id identifying the marker.
				4972	</p>
				4973
				4974	<h5>Semantics:</h5>
				4975
				4976	<p>
				4977	This intrinsic does not modify the behavior of the program. Backends that do not
				4978	support this intrinisic may ignore it.
				4979	</p>
				4980
				4981	</div>
				4982
				4983	<!-- _______________________________________________________________________ -->
				4984	<div class="doc_subsubsection">
				4985	<a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
				4986	</div>
				4987
				4988	<div class="doc_text">
				4989
				4990	<h5>Syntax:</h5>
				4991	<pre>
				4992	declare i64 @llvm.readcyclecounter( )
				4993	</pre>
				4994
				4995	<h5>Overview:</h5>
				4996
				4997
				4998	<p>
				4999	The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
				5000	counter register (or similar low latency, high accuracy clocks) on those targets
				5001	that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
				5002	As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
				5003	should only be used for small timings.
				5004	</p>
				5005
				5006	<h5>Semantics:</h5>
				5007
				5008	<p>
				5009	When directly supported, reading the cycle counter should not modify any memory.
				5010	Implementations are allowed to either return a application specific value or a
				5011	system wide value. On backends without support, this is lowered to a constant 0.
				5012	</p>
				5013
				5014	</div>
				5015
				5016	<!-- ======================================================================= -->
				5017	<div class="doc_subsection">
				5018	<a name="int_libc">Standard C Library Intrinsics</a>
				5019	</div>
				5020
				5021	<div class="doc_text">
				5022	<p>
				5023	LLVM provides intrinsics for a few important standard C library functions.
				5024	These intrinsics allow source-language front-ends to pass information about the
				5025	alignment of the pointer arguments to the code generator, providing opportunity
				5026	for more efficient code generation.
				5027	</p>
				5028
				5029	</div>
				5030
				5031	<!-- _______________________________________________________________________ -->
				5032	<div class="doc_subsubsection">
				5033	<a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
				5034	</div>
				5035
				5036	<div class="doc_text">
				5037
				5038	<h5>Syntax:</h5>
				5039	<pre>
				5040	declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
				5041	i32 <len>, i32 <align>)
				5042	declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>,
				5043	i64 <len>, i32 <align>)
				5044	</pre>
				5045
				5046	<h5>Overview:</h5>
				5047
				5048	<p>
				5049	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5050	location to the destination location.
				5051	</p>
				5052
				5053	<p>
				5054	Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
				5055	intrinsics do not return a value, and takes an extra alignment argument.
				5056	</p>
				5057
				5058	<h5>Arguments:</h5>
				5059
				5060	<p>
				5061	The first argument is a pointer to the destination, the second is a pointer to
				5062	the source. The third argument is an integer argument
				5063	specifying the number of bytes to copy, and the fourth argument is the alignment
				5064	of the source and destination locations.
				5065	</p>
				5066
				5067	<p>
				5068	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5069	the caller guarantees that both the source and destination pointers are aligned
				5070	to that boundary.
				5071	</p>
				5072
				5073	<h5>Semantics:</h5>
				5074
				5075	<p>
				5076	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5077	location to the destination location, which are not allowed to overlap. It
				5078	copies "len" bytes of memory over. If the argument is known to be aligned to
				5079	some boundary, this can be specified as the fourth argument, otherwise it should
				5080	be set to 0 or 1.
				5081	</p>
				5082	</div>
				5083
				5084
				5085	<!-- _______________________________________________________________________ -->
				5086	<div class="doc_subsubsection">
				5087	<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
				5088	</div>
				5089
				5090	<div class="doc_text">
				5091
				5092	<h5>Syntax:</h5>
				5093	<pre>
				5094	declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
				5095	i32 <len>, i32 <align>)
				5096	declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>,
				5097	i64 <len>, i32 <align>)
				5098	</pre>
				5099
				5100	<h5>Overview:</h5>
				5101
				5102	<p>
				5103	The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
				5104	location to the destination location. It is similar to the
Chris Lattner	dba16ea	2008-01-06 19:51:52 +0000	[diff] [blame]	5105	'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5106	</p>
				5107
				5108	<p>
				5109	Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
				5110	intrinsics do not return a value, and takes an extra alignment argument.
				5111	</p>
				5112
				5113	<h5>Arguments:</h5>
				5114
				5115	<p>
				5116	The first argument is a pointer to the destination, the second is a pointer to
				5117	the source. The third argument is an integer argument
				5118	specifying the number of bytes to copy, and the fourth argument is the alignment
				5119	of the source and destination locations.
				5120	</p>
				5121
				5122	<p>
				5123	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5124	the caller guarantees that the source and destination pointers are aligned to
				5125	that boundary.
				5126	</p>
				5127
				5128	<h5>Semantics:</h5>
				5129
				5130	<p>
				5131	The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
				5132	location to the destination location, which may overlap. It
				5133	copies "len" bytes of memory over. If the argument is known to be aligned to
				5134	some boundary, this can be specified as the fourth argument, otherwise it should
				5135	be set to 0 or 1.
				5136	</p>
				5137	</div>
				5138
				5139
				5140	<!-- _______________________________________________________________________ -->
				5141	<div class="doc_subsubsection">
				5142	<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
				5143	</div>
				5144
				5145	<div class="doc_text">
				5146
				5147	<h5>Syntax:</h5>
				5148	<pre>
				5149	declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
				5150	i32 <len>, i32 <align>)
				5151	declare void @llvm.memset.i64(i8 * <dest>, i8 <val>,
				5152	i64 <len>, i32 <align>)
				5153	</pre>
				5154
				5155	<h5>Overview:</h5>
				5156
				5157	<p>
				5158	The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
				5159	byte value.
				5160	</p>
				5161
				5162	<p>
				5163	Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
				5164	does not return a value, and takes an extra alignment argument.
				5165	</p>
				5166
				5167	<h5>Arguments:</h5>
				5168
				5169	<p>
				5170	The first argument is a pointer to the destination to fill, the second is the
				5171	byte value to fill it with, the third argument is an integer
				5172	argument specifying the number of bytes to fill, and the fourth argument is the
				5173	known alignment of destination location.
				5174	</p>
				5175
				5176	<p>
				5177	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5178	the caller guarantees that the destination pointer is aligned to that boundary.
				5179	</p>
				5180
				5181	<h5>Semantics:</h5>
				5182
				5183	<p>
				5184	The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
				5185	the
				5186	destination location. If the argument is known to be aligned to some boundary,
				5187	this can be specified as the fourth argument, otherwise it should be set to 0 or
				5188	1.
				5189	</p>
				5190	</div>
				5191
				5192
				5193	<!-- _______________________________________________________________________ -->
				5194	<div class="doc_subsubsection">
				5195	<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
				5196	</div>
				5197
				5198	<div class="doc_text">
				5199
				5200	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5201	<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5202	floating point or vector of floating point type. Not all targets support all
				5203	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5204	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5205	declare float @llvm.sqrt.f32(float %Val)
				5206	declare double @llvm.sqrt.f64(double %Val)
				5207	declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
				5208	declare fp128 @llvm.sqrt.f128(fp128 %Val)
				5209	declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5210	</pre>
				5211
				5212	<h5>Overview:</h5>
				5213
				5214	<p>
				5215	The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5216	returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5217	<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner	f914a00	2008-01-29 07:00:44 +0000	[diff] [blame]	5218	negative numbers other than -0.0 (which allows for better optimization, because
				5219	there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
				5220	defined to return -0.0 like IEEE sqrt.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5221	</p>
				5222
				5223	<h5>Arguments:</h5>
				5224
				5225	<p>
				5226	The argument and return value are floating point numbers of the same type.
				5227	</p>
				5228
				5229	<h5>Semantics:</h5>
				5230
				5231	<p>
				5232	This function returns the sqrt of the specified operand if it is a nonnegative
				5233	floating point number.
				5234	</p>
				5235	</div>
				5236
				5237	<!-- _______________________________________________________________________ -->
				5238	<div class="doc_subsubsection">
				5239	<a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
				5240	</div>
				5241
				5242	<div class="doc_text">
				5243
				5244	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5245	<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5246	floating point or vector of floating point type. Not all targets support all
				5247	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5248	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5249	declare float @llvm.powi.f32(float %Val, i32 %power)
				5250	declare double @llvm.powi.f64(double %Val, i32 %power)
				5251	declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
				5252	declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
				5253	declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5254	</pre>
				5255
				5256	<h5>Overview:</h5>
				5257
				5258	<p>
				5259	The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
				5260	specified (positive or negative) power. The order of evaluation of
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5261	multiplications is not defined. When a vector of floating point type is
				5262	used, the second argument remains a scalar integer value.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5263	</p>
				5264
				5265	<h5>Arguments:</h5>
				5266
				5267	<p>
				5268	The second argument is an integer power, and the first is a value to raise to
				5269	that power.
				5270	</p>
				5271
				5272	<h5>Semantics:</h5>
				5273
				5274	<p>
				5275	This function returns the first value raised to the second power with an
				5276	unspecified sequence of rounding operations.</p>
				5277	</div>
				5278
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5279	<!-- _______________________________________________________________________ -->
				5280	<div class="doc_subsubsection">
				5281	<a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
				5282	</div>
				5283
				5284	<div class="doc_text">
				5285
				5286	<h5>Syntax:</h5>
				5287	<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
				5288	floating point or vector of floating point type. Not all targets support all
				5289	types however.
				5290	<pre>
				5291	declare float @llvm.sin.f32(float %Val)
				5292	declare double @llvm.sin.f64(double %Val)
				5293	declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
				5294	declare fp128 @llvm.sin.f128(fp128 %Val)
				5295	declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
				5296	</pre>
				5297
				5298	<h5>Overview:</h5>
				5299
				5300	<p>
				5301	The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
				5302	</p>
				5303
				5304	<h5>Arguments:</h5>
				5305
				5306	<p>
				5307	The argument and return value are floating point numbers of the same type.
				5308	</p>
				5309
				5310	<h5>Semantics:</h5>
				5311
				5312	<p>
				5313	This function returns the sine of the specified operand, returning the
				5314	same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohman	eaba92e	2007-10-17 18:05:13 +0000	[diff] [blame]	5315	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5316	</div>
				5317
				5318	<!-- _______________________________________________________________________ -->
				5319	<div class="doc_subsubsection">
				5320	<a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
				5321	</div>
				5322
				5323	<div class="doc_text">
				5324
				5325	<h5>Syntax:</h5>
				5326	<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
				5327	floating point or vector of floating point type. Not all targets support all
				5328	types however.
				5329	<pre>
				5330	declare float @llvm.cos.f32(float %Val)
				5331	declare double @llvm.cos.f64(double %Val)
				5332	declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
				5333	declare fp128 @llvm.cos.f128(fp128 %Val)
				5334	declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
				5335	</pre>
				5336
				5337	<h5>Overview:</h5>
				5338
				5339	<p>
				5340	The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
				5341	</p>
				5342
				5343	<h5>Arguments:</h5>
				5344
				5345	<p>
				5346	The argument and return value are floating point numbers of the same type.
				5347	</p>
				5348
				5349	<h5>Semantics:</h5>
				5350
				5351	<p>
				5352	This function returns the cosine of the specified operand, returning the
				5353	same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohman	eaba92e	2007-10-17 18:05:13 +0000	[diff] [blame]	5354	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5355	</div>
				5356
				5357	<!-- _______________________________________________________________________ -->
				5358	<div class="doc_subsubsection">
				5359	<a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
				5360	</div>
				5361
				5362	<div class="doc_text">
				5363
				5364	<h5>Syntax:</h5>
				5365	<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
				5366	floating point or vector of floating point type. Not all targets support all
				5367	types however.
				5368	<pre>
				5369	declare float @llvm.pow.f32(float %Val, float %Power)
				5370	declare double @llvm.pow.f64(double %Val, double %Power)
				5371	declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
				5372	declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
				5373	declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
				5374	</pre>
				5375
				5376	<h5>Overview:</h5>
				5377
				5378	<p>
				5379	The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
				5380	specified (positive or negative) power.
				5381	</p>
				5382
				5383	<h5>Arguments:</h5>
				5384
				5385	<p>
				5386	The second argument is a floating point power, and the first is a value to
				5387	raise to that power.
				5388	</p>
				5389
				5390	<h5>Semantics:</h5>
				5391
				5392	<p>
				5393	This function returns the first value raised to the second power,
				5394	returning the
				5395	same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohman	eaba92e	2007-10-17 18:05:13 +0000	[diff] [blame]	5396	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5397	</div>
				5398
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5399
				5400	<!-- ======================================================================= -->
				5401	<div class="doc_subsection">
				5402	<a name="int_manip">Bit Manipulation Intrinsics</a>
				5403	</div>
				5404
				5405	<div class="doc_text">
				5406	<p>
				5407	LLVM provides intrinsics for a few important bit manipulation operations.
				5408	These allow efficient code generation for some algorithms.
				5409	</p>
				5410
				5411	</div>
				5412
				5413	<!-- _______________________________________________________________________ -->
				5414	<div class="doc_subsubsection">
				5415	<a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
				5416	</div>
				5417
				5418	<div class="doc_text">
				5419
				5420	<h5>Syntax:</h5>
				5421	<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5422	type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5423	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5424	declare i16 @llvm.bswap.i16(i16 <id>)
				5425	declare i32 @llvm.bswap.i32(i32 <id>)
				5426	declare i64 @llvm.bswap.i64(i64 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5427	</pre>
				5428
				5429	<h5>Overview:</h5>
				5430
				5431	<p>
				5432	The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
				5433	values with an even number of bytes (positive multiple of 16 bits). These are
				5434	useful for performing operations on data that is not in the target's native
				5435	byte order.
				5436	</p>
				5437
				5438	<h5>Semantics:</h5>
				5439
				5440	<p>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5441	The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5442	and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
				5443	intrinsic returns an i32 value that has the four bytes of the input i32
				5444	swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5445	i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
				5446	<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5447	additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
				5448	</p>
				5449
				5450	</div>
				5451
				5452	<!-- _______________________________________________________________________ -->
				5453	<div class="doc_subsubsection">
				5454	<a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
				5455	</div>
				5456
				5457	<div class="doc_text">
				5458
				5459	<h5>Syntax:</h5>
				5460	<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
				5461	width. Not all targets support all bit widths however.
				5462	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5463	declare i8 @llvm.ctpop.i8 (i8 <src>)
				5464	declare i16 @llvm.ctpop.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5465	declare i32 @llvm.ctpop.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5466	declare i64 @llvm.ctpop.i64(i64 <src>)
				5467	declare i256 @llvm.ctpop.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5468	</pre>
				5469
				5470	<h5>Overview:</h5>
				5471
				5472	<p>
				5473	The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
				5474	value.
				5475	</p>
				5476
				5477	<h5>Arguments:</h5>
				5478
				5479	<p>
				5480	The only argument is the value to be counted. The argument may be of any
				5481	integer type. The return type must match the argument type.
				5482	</p>
				5483
				5484	<h5>Semantics:</h5>
				5485
				5486	<p>
				5487	The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
				5488	</p>
				5489	</div>
				5490
				5491	<!-- _______________________________________________________________________ -->
				5492	<div class="doc_subsubsection">
				5493	<a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
				5494	</div>
				5495
				5496	<div class="doc_text">
				5497
				5498	<h5>Syntax:</h5>
				5499	<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
				5500	integer bit width. Not all targets support all bit widths however.
				5501	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5502	declare i8 @llvm.ctlz.i8 (i8 <src>)
				5503	declare i16 @llvm.ctlz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5504	declare i32 @llvm.ctlz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5505	declare i64 @llvm.ctlz.i64(i64 <src>)
				5506	declare i256 @llvm.ctlz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5507	</pre>
				5508
				5509	<h5>Overview:</h5>
				5510
				5511	<p>
				5512	The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
				5513	leading zeros in a variable.
				5514	</p>
				5515
				5516	<h5>Arguments:</h5>
				5517
				5518	<p>
				5519	The only argument is the value to be counted. The argument may be of any
				5520	integer type. The return type must match the argument type.
				5521	</p>
				5522
				5523	<h5>Semantics:</h5>
				5524
				5525	<p>
				5526	The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
				5527	in a variable. If the src == 0 then the result is the size in bits of the type
				5528	of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
				5529	</p>
				5530	</div>
				5531
				5532
				5533
				5534	<!-- _______________________________________________________________________ -->
				5535	<div class="doc_subsubsection">
				5536	<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
				5537	</div>
				5538
				5539	<div class="doc_text">
				5540
				5541	<h5>Syntax:</h5>
				5542	<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
				5543	integer bit width. Not all targets support all bit widths however.
				5544	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5545	declare i8 @llvm.cttz.i8 (i8 <src>)
				5546	declare i16 @llvm.cttz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5547	declare i32 @llvm.cttz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5548	declare i64 @llvm.cttz.i64(i64 <src>)
				5549	declare i256 @llvm.cttz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5550	</pre>
				5551
				5552	<h5>Overview:</h5>
				5553
				5554	<p>
				5555	The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
				5556	trailing zeros.
				5557	</p>
				5558
				5559	<h5>Arguments:</h5>
				5560
				5561	<p>
				5562	The only argument is the value to be counted. The argument may be of any
				5563	integer type. The return type must match the argument type.
				5564	</p>
				5565
				5566	<h5>Semantics:</h5>
				5567
				5568	<p>
				5569	The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
				5570	in a variable. If the src == 0 then the result is the size in bits of the type
				5571	of src. For example, <tt>llvm.cttz(2) = 1</tt>.
				5572	</p>
				5573	</div>
				5574
				5575	<!-- _______________________________________________________________________ -->
				5576	<div class="doc_subsubsection">
				5577	<a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
				5578	</div>
				5579
				5580	<div class="doc_text">
				5581
				5582	<h5>Syntax:</h5>
				5583	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
				5584	on any integer bit width.
				5585	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5586	declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
				5587	declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5588	</pre>
				5589
				5590	<h5>Overview:</h5>
				5591	<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
				5592	range of bits from an integer value and returns them in the same bit width as
				5593	the original value.</p>
				5594
				5595	<h5>Arguments:</h5>
				5596	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5597	any bit width but they must have the same bit width. The second and third
				5598	arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
				5599
				5600	<h5>Semantics:</h5>
				5601	<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
				5602	of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
				5603	<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
				5604	operates in forward mode.</p>
				5605	<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
				5606	right by <tt>%loBit</tt> bits and then ANDing it with a mask with
				5607	only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
				5608	<ol>
				5609	<li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
				5610	by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
				5611	<li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
				5612	to determine the number of bits to retain.</li>
				5613	<li>A mask of the retained bits is created by shifting a -1 value.</li>
				5614	<li>The mask is ANDed with <tt>%val</tt> to produce the result.
				5615	</ol>
				5616	<p>In reverse mode, a similar computation is made except that the bits are
				5617	returned in the reverse order. So, for example, if <tt>X</tt> has the value
				5618	<tt>i16 0x0ACF (101011001111)</tt> and we apply
				5619	<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
				5620	<tt>i16 0x0026 (000000100110)</tt>.</p>
				5621	</div>
				5622
				5623	<div class="doc_subsubsection">
				5624	<a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
				5625	</div>
				5626
				5627	<div class="doc_text">
				5628
				5629	<h5>Syntax:</h5>
				5630	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
				5631	on any integer bit width.
				5632	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5633	declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
				5634	declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5635	</pre>
				5636
				5637	<h5>Overview:</h5>
				5638	<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
				5639	of bits in an integer value with another integer value. It returns the integer
				5640	with the replaced bits.</p>
				5641
				5642	<h5>Arguments:</h5>
				5643	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5644	any bit width but they must have the same bit width. <tt>%val</tt> is the value
				5645	whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
				5646	integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
				5647	type since they specify only a bit index.</p>
				5648
				5649	<h5>Semantics:</h5>
				5650	<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
				5651	of operation: forwards and reverse. If <tt>%lo</tt> is greater than
				5652	<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
				5653	operates in forward mode.</p>
				5654	<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
				5655	truncating it down to the size of the replacement area or zero extending it
				5656	up to that size.</p>
				5657	<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
				5658	are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
				5659	in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
				5660	to the <tt>%hi</tt>th bit.
				5661	<p>In reverse mode, a similar computation is made except that the bits are
				5662	reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
				5663	<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
				5664	<h5>Examples:</h5>
				5665	<pre>
				5666	llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
				5667	llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
				5668	llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F
				5669	llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
				5670	llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
				5671	</pre>
				5672	</div>
				5673
				5674	<!-- ======================================================================= -->
				5675	<div class="doc_subsection">
				5676	<a name="int_debugger">Debugger Intrinsics</a>
				5677	</div>
				5678
				5679	<div class="doc_text">
				5680	<p>
				5681	The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
				5682	are described in the <a
				5683	href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
				5684	Debugging</a> document.
				5685	</p>
				5686	</div>
				5687
				5688
				5689	<!-- ======================================================================= -->
				5690	<div class="doc_subsection">
				5691	<a name="int_eh">Exception Handling Intrinsics</a>
				5692	</div>
				5693
				5694	<div class="doc_text">
				5695	<p> The LLVM exception handling intrinsics (which all start with
				5696	<tt>llvm.eh.</tt> prefix), are described in the <a
				5697	href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
				5698	Handling</a> document. </p>
				5699	</div>
				5700
				5701	<!-- ======================================================================= -->
				5702	<div class="doc_subsection">
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5703	<a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5704	</div>
				5705
				5706	<div class="doc_text">
				5707	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5708	This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5709	the <tt>nest</tt> attribute, from a function. The result is a callable
				5710	function pointer lacking the nest parameter - the caller does not need
				5711	to provide a value for it. Instead, the value to use is stored in
				5712	advance in a "trampoline", a block of memory usually allocated
				5713	on the stack, which also contains code to splice the nest value into the
				5714	argument list. This is used to implement the GCC nested function address
				5715	extension.
				5716	</p>
				5717	<p>
				5718	For example, if the function is
				5719	<tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling	e262b4c	2007-09-22 09:23:55 +0000	[diff] [blame]	5720	pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5721	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5722	%tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
				5723	%tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
				5724	%p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8), i8 %nval )
				5725	%fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5726	</pre>
Bill Wendling	e262b4c	2007-09-22 09:23:55 +0000	[diff] [blame]	5727	<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
				5728	to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5729	</div>
				5730
				5731	<!-- _______________________________________________________________________ -->
				5732	<div class="doc_subsubsection">
				5733	<a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
				5734	</div>
				5735	<div class="doc_text">
				5736	<h5>Syntax:</h5>
				5737	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5738	declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5739	</pre>
				5740	<h5>Overview:</h5>
				5741	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5742	This fills the memory pointed to by <tt>tramp</tt> with code
				5743	and returns a function pointer suitable for executing it.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5744	</p>
				5745	<h5>Arguments:</h5>
				5746	<p>
				5747	The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
				5748	pointers. The <tt>tramp</tt> argument must point to a sufficiently large
				5749	and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands	3501221	2007-08-22 23:39:54 +0000	[diff] [blame]	5750	intrinsic. Note that the size and the alignment are target-specific - LLVM
				5751	currently provides no portable way of determining them, so a front-end that
				5752	generates this intrinsic needs to have some target-specific knowledge.
				5753	The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5754	</p>
				5755	<h5>Semantics:</h5>
				5756	<p>
				5757	The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5758	dependent code, turning it into a function. A pointer to this function is
				5759	returned, but needs to be bitcast to an
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5760	<a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5761	before being called. The new function's signature is the same as that of
				5762	<tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
				5763	removed. At most one such <tt>nest</tt> argument is allowed, and it must be
				5764	of pointer type. Calling the new function is equivalent to calling
				5765	<tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
				5766	missing <tt>nest</tt> argument. If, after calling
				5767	<tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
				5768	modified, then the effect of any later call to the returned function pointer is
				5769	undefined.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5770	</p>
				5771	</div>
				5772
				5773	<!-- ======================================================================= -->
				5774	<div class="doc_subsection">
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5775	<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
				5776	</div>
				5777
				5778	<div class="doc_text">
				5779	<p>
				5780	These intrinsic functions expand the "universal IR" of LLVM to represent
				5781	hardware constructs for atomic operations and memory synchronization. This
				5782	provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	5783	is aimed at a low enough level to allow any programming models or APIs
				5784	(Application Programming Interfaces) which
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5785	need atomic behaviors to map cleanly onto it. It is also modeled primarily on
				5786	hardware behavior. Just as hardware provides a "universal IR" for source
				5787	languages, it also provides a starting point for developing a "universal"
				5788	atomic operation and synchronization IR.
				5789	</p>
				5790	<p>
				5791	These do <em>not</em> form an API such as high-level threading libraries,
				5792	software transaction memory systems, atomic primitives, and intrinsic
				5793	functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
				5794	application libraries. The hardware interface provided by LLVM should allow
				5795	a clean implementation of all of these APIs and parallel programming models.
				5796	No one model or paradigm should be selected above others unless the hardware
				5797	itself ubiquitously does so.
				5798
				5799	</p>
				5800	</div>
				5801
				5802	<!-- _______________________________________________________________________ -->
				5803	<div class="doc_subsubsection">
				5804	<a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
				5805	</div>
				5806	<div class="doc_text">
				5807	<h5>Syntax:</h5>
				5808	<pre>
				5809	declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>,
				5810	i1 <device> )
				5811
				5812	</pre>
				5813	<h5>Overview:</h5>
				5814	<p>
				5815	The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
				5816	specific pairs of memory access types.
				5817	</p>
				5818	<h5>Arguments:</h5>
				5819	<p>
				5820	The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
				5821	The first four arguments enables a specific barrier as listed below. The fith
				5822	argument specifies that the barrier applies to io or device or uncached memory.
				5823
				5824	</p>
				5825	<ul>
				5826	<li><tt>ll</tt>: load-load barrier</li>
				5827	<li><tt>ls</tt>: load-store barrier</li>
				5828	<li><tt>sl</tt>: store-load barrier</li>
				5829	<li><tt>ss</tt>: store-store barrier</li>
				5830	<li><tt>device</tt>: barrier applies to device and uncached memory also.
				5831	</ul>
				5832	<h5>Semantics:</h5>
				5833	<p>
				5834	This intrinsic causes the system to enforce some ordering constraints upon
				5835	the loads and stores of the program. This barrier does not indicate
				5836	<em>when</em> any events will occur, it only enforces an <em>order</em> in
				5837	which they occur. For any of the specified pairs of load and store operations
				5838	(f.ex. load-load, or store-load), all of the first operations preceding the
				5839	barrier will complete before any of the second operations succeeding the
				5840	barrier begin. Specifically the semantics for each pairing is as follows:
				5841	</p>
				5842	<ul>
				5843	<li><tt>ll</tt>: All loads before the barrier must complete before any load
				5844	after the barrier begins.</li>
				5845
				5846	<li><tt>ls</tt>: All loads before the barrier must complete before any
				5847	store after the barrier begins.</li>
				5848	<li><tt>ss</tt>: All stores before the barrier must complete before any
				5849	store after the barrier begins.</li>
				5850	<li><tt>sl</tt>: All stores before the barrier must complete before any
				5851	load after the barrier begins.</li>
				5852	</ul>
				5853	<p>
				5854	These semantics are applied with a logical "and" behavior when more than one
				5855	is enabled in a single memory barrier intrinsic.
				5856	</p>
				5857	<p>
				5858	Backends may implement stronger barriers than those requested when they do not
				5859	support as fine grained a barrier as requested. Some architectures do not
				5860	need all types of barriers and on such architectures, these become noops.
				5861	</p>
				5862	<h5>Example:</h5>
				5863	<pre>
				5864	%ptr = malloc i32
				5865	store i32 4, %ptr
				5866
				5867	%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
				5868	call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
				5869	<i>; guarantee the above finishes</i>
				5870	store i32 8, %ptr <i>; before this begins</i>
				5871	</pre>
				5872	</div>
				5873
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5874	<!-- _______________________________________________________________________ -->
				5875	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5876	<a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5877	</div>
				5878	<div class="doc_text">
				5879	<h5>Syntax:</h5>
				5880	<p>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5881	This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
				5882	any integer bit width and for different address spaces. Not all targets
				5883	support all bit widths however.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5884
				5885	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5886	declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
				5887	declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
				5888	declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
				5889	declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* <ptr>, i64 <cmp>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5890
				5891	</pre>
				5892	<h5>Overview:</h5>
				5893	<p>
				5894	This loads a value in memory and compares it to a given value. If they are
				5895	equal, it stores a new value into the memory.
				5896	</p>
				5897	<h5>Arguments:</h5>
				5898	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5899	The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5900	well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
				5901	same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
				5902	this integer type. While any bit width integer may be used, targets may only
				5903	lower representations they support in hardware.
				5904
				5905	</p>
				5906	<h5>Semantics:</h5>
				5907	<p>
				5908	This entire intrinsic must be executed atomically. It first loads the value
				5909	in memory pointed to by <tt>ptr</tt> and compares it with the value
				5910	<tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
				5911	loaded value is yielded in all cases. This provides the equivalent of an
				5912	atomic compare-and-swap operation within the SSA framework.
				5913	</p>
				5914	<h5>Examples:</h5>
				5915
				5916	<pre>
				5917	%ptr = malloc i32
				5918	store i32 4, %ptr
				5919
				5920	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5921	%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5922	<i>; yields {i32}:result1 = 4</i>
				5923	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5924	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5925
				5926	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5927	%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5928	<i>; yields {i32}:result2 = 8</i>
				5929	%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
				5930
				5931	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
				5932	</pre>
				5933	</div>
				5934
				5935	<!-- _______________________________________________________________________ -->
				5936	<div class="doc_subsubsection">
				5937	<a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
				5938	</div>
				5939	<div class="doc_text">
				5940	<h5>Syntax:</h5>
				5941
				5942	<p>
				5943	This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
				5944	integer bit width. Not all targets support all bit widths however.</p>
				5945	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5946	declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
				5947	declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
				5948	declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
				5949	declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5950
				5951	</pre>
				5952	<h5>Overview:</h5>
				5953	<p>
				5954	This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
				5955	the value from memory. It then stores the value in <tt>val</tt> in the memory
				5956	at <tt>ptr</tt>.
				5957	</p>
				5958	<h5>Arguments:</h5>
				5959
				5960	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5961	The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5962	<tt>val</tt> argument and the result must be integers of the same bit width.
				5963	The first argument, <tt>ptr</tt>, must be a pointer to a value of this
				5964	integer type. The targets may only lower integer representations they
				5965	support.
				5966	</p>
				5967	<h5>Semantics:</h5>
				5968	<p>
				5969	This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
				5970	stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
				5971	equivalent of an atomic swap operation within the SSA framework.
				5972
				5973	</p>
				5974	<h5>Examples:</h5>
				5975	<pre>
				5976	%ptr = malloc i32
				5977	store i32 4, %ptr
				5978
				5979	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5980	%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5981	<i>; yields {i32}:result1 = 4</i>
				5982	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5983	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5984
				5985	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5986	%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5987	<i>; yields {i32}:result2 = 8</i>
				5988
				5989	%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
				5990	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
				5991	</pre>
				5992	</div>
				5993
				5994	<!-- _______________________________________________________________________ -->
				5995	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5996	<a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5997
				5998	</div>
				5999	<div class="doc_text">
				6000	<h5>Syntax:</h5>
				6001	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6002	This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6003	integer bit width. Not all targets support all bit widths however.</p>
				6004	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6005	declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
				6006	declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
				6007	declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
				6008	declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6009
				6010	</pre>
				6011	<h5>Overview:</h5>
				6012	<p>
				6013	This intrinsic adds <tt>delta</tt> to the value stored in memory at
				6014	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6015	</p>
				6016	<h5>Arguments:</h5>
				6017	<p>
				6018
				6019	The intrinsic takes two arguments, the first a pointer to an integer value
				6020	and the second an integer value. The result is also an integer value. These
				6021	integer types can have any bit width, but they must all have the same bit
				6022	width. The targets may only lower integer representations they support.
				6023	</p>
				6024	<h5>Semantics:</h5>
				6025	<p>
				6026	This intrinsic does a series of operations atomically. It first loads the
				6027	value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
				6028	to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6029	</p>
				6030
				6031	<h5>Examples:</h5>
				6032	<pre>
				6033	%ptr = malloc i32
				6034	store i32 4, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6035	%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6036	<i>; yields {i32}:result1 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6037	%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6038	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6039	%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6040	<i>; yields {i32}:result3 = 10</i>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6041	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6042	</pre>
				6043	</div>
				6044
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6045	<!-- _______________________________________________________________________ -->
				6046	<div class="doc_subsubsection">
				6047	<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
				6048
				6049	</div>
				6050	<div class="doc_text">
				6051	<h5>Syntax:</h5>
				6052	<p>
				6053	This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6054	any integer bit width and for different address spaces. Not all targets
				6055	support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6056	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6057	declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
				6058	declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
				6059	declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
				6060	declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6061
				6062	</pre>
				6063	<h5>Overview:</h5>
				6064	<p>
				6065	This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
				6066	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6067	</p>
				6068	<h5>Arguments:</h5>
				6069	<p>
				6070
				6071	The intrinsic takes two arguments, the first a pointer to an integer value
				6072	and the second an integer value. The result is also an integer value. These
				6073	integer types can have any bit width, but they must all have the same bit
				6074	width. The targets may only lower integer representations they support.
				6075	</p>
				6076	<h5>Semantics:</h5>
				6077	<p>
				6078	This intrinsic does a series of operations atomically. It first loads the
				6079	value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
				6080	result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6081	</p>
				6082
				6083	<h5>Examples:</h5>
				6084	<pre>
				6085	%ptr = malloc i32
				6086	store i32 8, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6087	%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6088	<i>; yields {i32}:result1 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6089	%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6090	<i>; yields {i32}:result2 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6091	%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6092	<i>; yields {i32}:result3 = 2</i>
				6093	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
				6094	</pre>
				6095	</div>
				6096
				6097	<!-- _______________________________________________________________________ -->
				6098	<div class="doc_subsubsection">
				6099	<a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
				6100	<a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
				6101	<a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
				6102	<a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
				6103
				6104	</div>
				6105	<div class="doc_text">
				6106	<h5>Syntax:</h5>
				6107	<p>
				6108	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
				6109	<tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6110	<tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
				6111	address spaces. Not all targets support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6112	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6113	declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
				6114	declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
				6115	declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
				6116	declare i64 @llvm.atomic.load.and.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6117
				6118	</pre>
				6119
				6120	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6121	declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
				6122	declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
				6123	declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
				6124	declare i64 @llvm.atomic.load.or.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6125
				6126	</pre>
				6127
				6128	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6129	declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
				6130	declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
				6131	declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
				6132	declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6133
				6134	</pre>
				6135
				6136	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6137	declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
				6138	declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
				6139	declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
				6140	declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6141
				6142	</pre>
				6143	<h5>Overview:</h5>
				6144	<p>
				6145	These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
				6146	the value stored in memory at <tt>ptr</tt>. It yields the original value
				6147	at <tt>ptr</tt>.
				6148	</p>
				6149	<h5>Arguments:</h5>
				6150	<p>
				6151
				6152	These intrinsics take two arguments, the first a pointer to an integer value
				6153	and the second an integer value. The result is also an integer value. These
				6154	integer types can have any bit width, but they must all have the same bit
				6155	width. The targets may only lower integer representations they support.
				6156	</p>
				6157	<h5>Semantics:</h5>
				6158	<p>
				6159	These intrinsics does a series of operations atomically. They first load the
				6160	value stored at <tt>ptr</tt>. They then do the bitwise operation
				6161	<tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
				6162	value stored at <tt>ptr</tt>.
				6163	</p>
				6164
				6165	<h5>Examples:</h5>
				6166	<pre>
				6167	%ptr = malloc i32
				6168	store i32 0x0F0F, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6169	%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6170	<i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6171	%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6172	<i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6173	%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6174	<i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6175	%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6176	<i>; yields {i32}:result3 = FF</i>
				6177	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
				6178	</pre>
				6179	</div>
				6180
				6181
				6182	<!-- _______________________________________________________________________ -->
				6183	<div class="doc_subsubsection">
				6184	<a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
				6185	<a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
				6186	<a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
				6187	<a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
				6188
				6189	</div>
				6190	<div class="doc_text">
				6191	<h5>Syntax:</h5>
				6192	<p>
				6193	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
				6194	<tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6195	<tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
				6196	address spaces. Not all targets
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6197	support all bit widths however.</p>
				6198	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6199	declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
				6200	declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
				6201	declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
				6202	declare i64 @llvm.atomic.load.max.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6203
				6204	</pre>
				6205
				6206	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6207	declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
				6208	declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
				6209	declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
				6210	declare i64 @llvm.atomic.load.min.i64..p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6211
				6212	</pre>
				6213
				6214	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6215	declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
				6216	declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
				6217	declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
				6218	declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6219
				6220	</pre>
				6221
				6222	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6223	declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
				6224	declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
				6225	declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
				6226	declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6227
				6228	</pre>
				6229	<h5>Overview:</h5>
				6230	<p>
				6231	These intrinsics takes the signed or unsigned minimum or maximum of
				6232	<tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
				6233	original value at <tt>ptr</tt>.
				6234	</p>
				6235	<h5>Arguments:</h5>
				6236	<p>
				6237
				6238	These intrinsics take two arguments, the first a pointer to an integer value
				6239	and the second an integer value. The result is also an integer value. These
				6240	integer types can have any bit width, but they must all have the same bit
				6241	width. The targets may only lower integer representations they support.
				6242	</p>
				6243	<h5>Semantics:</h5>
				6244	<p>
				6245	These intrinsics does a series of operations atomically. They first load the
				6246	value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
				6247	<tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
				6248	the original value stored at <tt>ptr</tt>.
				6249	</p>
				6250
				6251	<h5>Examples:</h5>
				6252	<pre>
				6253	%ptr = malloc i32
				6254	store i32 7, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6255	%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6256	<i>; yields {i32}:result0 = 7</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6257	%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6258	<i>; yields {i32}:result1 = -2</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6259	%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6260	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6261	%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6262	<i>; yields {i32}:result3 = 8</i>
				6263	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
				6264	</pre>
				6265	</div>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6266
				6267	<!-- ======================================================================= -->
				6268	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6269	<a name="int_general">General Intrinsics</a>
				6270	</div>
				6271
				6272	<div class="doc_text">
				6273	<p> This class of intrinsics is designed to be generic and has
				6274	no specific purpose. </p>
				6275	</div>
				6276
				6277	<!-- _______________________________________________________________________ -->
				6278	<div class="doc_subsubsection">
				6279	<a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
				6280	</div>
				6281
				6282	<div class="doc_text">
				6283
				6284	<h5>Syntax:</h5>
				6285	<pre>
				6286	declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> )
				6287	</pre>
				6288
				6289	<h5>Overview:</h5>
				6290
				6291	<p>
				6292	The '<tt>llvm.var.annotation</tt>' intrinsic
				6293	</p>
				6294
				6295	<h5>Arguments:</h5>
				6296
				6297	<p>
				6298	The first argument is a pointer to a value, the second is a pointer to a
				6299	global string, the third is a pointer to a global string which is the source
				6300	file name, and the last argument is the line number.
				6301	</p>
				6302
				6303	<h5>Semantics:</h5>
				6304
				6305	<p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6306	This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6307	This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6308	annotations. These have no other defined use, they are ignored by code
				6309	generation and optimization.
				6310	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6311	</div>
				6312
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6313	<!-- _______________________________________________________________________ -->
				6314	<div class="doc_subsubsection">
Tanya Lattner	c9869b1	2007-09-21 23:57:59 +0000	[diff] [blame]	6315	<a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6316	</div>
				6317
				6318	<div class="doc_text">
				6319
				6320	<h5>Syntax:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6321	<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
				6322	any integer bit width.
				6323	</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6324	<pre>
Tanya Lattner	09161fe	2007-09-22 00:03:01 +0000	[diff] [blame]	6325	declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
				6326	declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
				6327	declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> )
				6328	declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> )
				6329	declare i256 @llvm.annotation.i256(i256 <val>, i8* <str>, i8* <str>, i32 <int> )
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6330	</pre>
				6331
				6332	<h5>Overview:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6333
				6334	<p>
				6335	The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6336	</p>
				6337
				6338	<h5>Arguments:</h5>
				6339
				6340	<p>
				6341	The first argument is an integer value (result of some expression),
				6342	the second is a pointer to a global string, the third is a pointer to a global
				6343	string which is the source file name, and the last argument is the line number.
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6344	It returns the value of the first argument.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6345	</p>
				6346
				6347	<h5>Semantics:</h5>
				6348
				6349	<p>
				6350	This intrinsic allows annotations to be put on arbitrary expressions
				6351	with arbitrary strings. This can be useful for special purpose optimizations
				6352	that want to look for these annotations. These have no other defined use, they
				6353	are ignored by code generation and optimization.
				6354	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6355
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6356	<!-- _______________________________________________________________________ -->
				6357	<div class="doc_subsubsection">
				6358	<a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
				6359	</div>
				6360
				6361	<div class="doc_text">
				6362
				6363	<h5>Syntax:</h5>
				6364	<pre>
				6365	declare void @llvm.trap()
				6366	</pre>
				6367
				6368	<h5>Overview:</h5>
				6369
				6370	<p>
				6371	The '<tt>llvm.trap</tt>' intrinsic
				6372	</p>
				6373
				6374	<h5>Arguments:</h5>
				6375
				6376	<p>
				6377	None
				6378	</p>
				6379
				6380	<h5>Semantics:</h5>
				6381
				6382	<p>
				6383	This intrinsics is lowered to the target dependent trap instruction. If the
				6384	target does not have a trap instruction, this intrinsic will be lowered to the
				6385	call of the abort() function.
				6386	</p>
				6387	</div>
				6388
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6389	<!-- *********************************************************************** -->
				6390	<hr>
				6391	<address>
				6392	<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
				6393	src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	6395	src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6396
				6397	<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
				6398	<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
				6399	Last modified: $Date$
				6400	</address>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	6401
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6402	</body>
				6403	</html>