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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>
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	29	<li><a href="#gc">Garbage Collector Names</a></li>
Devang Patel	25928cb	2008-09-04 23:10:26 +0000	[diff] [blame]	30	<li><a href="#notes">Function Notes</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>,
				755	an optional <a href="#notes">function notes</a>, an
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	756	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]	757
				758	LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
				759	optional <a href="#linkage">linkage type</a>, an optional
				760	<a href="#visibility">visibility style</a>, an optional
				761	<a href="#callingconv">calling convention</a>, a return type, an optional
				762	<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	763	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]	764	<a href="#gc">garbage collector name</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	765
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	766	<p>A function definition contains a list of basic blocks, forming the CFG
				767	(Control Flow Graph) for
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	768	the function. Each basic block may optionally start with a label (giving the
				769	basic block a symbol table entry), contains a list of instructions, and ends
				770	with a <a href="#terminators">terminator</a> instruction (such as a branch or
				771	function return).</p>
				772
				773	<p>The first basic block in a function is special in two ways: it is immediately
				774	executed on entrance to the function, and it is not allowed to have predecessor
				775	basic blocks (i.e. there can not be any branches to the entry block of a
				776	function). Because the block can have no predecessors, it also cannot have any
				777	<a href="#i_phi">PHI nodes</a>.</p>
				778
				779	<p>LLVM allows an explicit section to be specified for functions. If the target
				780	supports it, it will emit functions to the section specified.</p>
				781
				782	<p>An explicit alignment may be specified for a function. If not present, or if
				783	the alignment is set to zero, the alignment of the function is set by the target
				784	to whatever it feels convenient. If an explicit alignment is specified, the
				785	function is forced to have at least that much alignment. All alignments must be
				786	a power of 2.</p>
				787
				788	</div>
				789
				790
				791	<!-- ======================================================================= -->
				792	<div class="doc_subsection">
				793	<a name="aliasstructure">Aliases</a>
				794	</div>
				795	<div class="doc_text">
				796	<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]	797	function, global variable, another alias or bitcast of global value). Aliases
				798	may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	799	optional <a href="#visibility">visibility style</a>.</p>
				800
				801	<h5>Syntax:</h5>
				802
				803	<div class="doc_code">
				804	<pre>
				805	@<Name> = [Linkage] [Visibility] alias <AliaseeTy> @<Aliasee>
				806	</pre>
				807	</div>
				808
				809	</div>
				810
				811
				812
				813	<!-- ======================================================================= -->
				814	<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
				815	<div class="doc_text">
				816	<p>The return type and each parameter of a function type may have a set of
				817	<i>parameter attributes</i> associated with them. Parameter attributes are
				818	used to communicate additional information about the result or parameters of
Duncan Sands	f5588dc	2007-11-27 13:23:08 +0000	[diff] [blame]	819	a function. Parameter attributes are considered to be part of the function,
				820	not of the function type, so functions with different parameter attributes
				821	can have the same function type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	822
				823	<p>Parameter attributes are simple keywords that follow the type specified. If
				824	multiple parameter attributes are needed, they are space separated. For
				825	example:</p>
				826
				827	<div class="doc_code">
				828	<pre>
Duncan Sands	f5588dc	2007-11-27 13:23:08 +0000	[diff] [blame]	829	declare i32 @printf(i8* noalias , ...) nounwind
				830	declare i32 @atoi(i8*) nounwind readonly
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	831	</pre>
				832	</div>
				833
Duncan Sands	f5588dc	2007-11-27 13:23:08 +0000	[diff] [blame]	834	<p>Note that any attributes for the function result (<tt>nounwind</tt>,
				835	<tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	836
				837	<p>Currently, only the following parameter attributes are defined:</p>
				838	<dl>
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	839	<dt><tt>zeroext</tt></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	840	<dd>This indicates that the parameter should be zero extended just before
				841	a call to this function.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	842
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	843	<dt><tt>signext</tt></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	844	<dd>This indicates that the parameter should be sign extended just before
				845	a call to this function.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	846
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	847	<dt><tt>inreg</tt></dt>
				848	<dd>This indicates that the parameter should be placed in register (if
				849	possible) during assembling function call. Support for this attribute is
				850	target-specific</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	851
				852	<dt><tt>byval</tt></dt>
Chris Lattner	04c8618	2008-01-15 04:34:22 +0000	[diff] [blame]	853	<dd>This indicates that the pointer parameter should really be passed by
				854	value to the function. The attribute implies that a hidden copy of the
				855	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]	856	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]	857	pointer arguments. It is generally used to pass structs and arrays by
				858	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]	859
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	860	<dt><tt>sret</tt></dt>
Duncan Sands	616cc03	2008-02-18 04:19:38 +0000	[diff] [blame]	861	<dd>This indicates that the pointer parameter specifies the address of a
				862	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]	863	Loads and stores to the structure are assumed not to trap.
Duncan Sands	616cc03	2008-02-18 04:19:38 +0000	[diff] [blame]	864	May only be applied to the first parameter.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	865
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	866	<dt><tt>noalias</tt></dt>
Owen Anderson	c4fc4cd	2008-02-18 04:09:01 +0000	[diff] [blame]	867	<dd>This indicates that the parameter does not alias any global or any other
				868	parameter. The caller is responsible for ensuring that this is the case,
				869	usually by placing the value in a stack allocation.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	870
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	871	<dt><tt>noreturn</tt></dt>
				872	<dd>This function attribute indicates that the function never returns. This
				873	indicates to LLVM that every call to this function should be treated as if
				874	an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	875
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	876	<dt><tt>nounwind</tt></dt>
Duncan Sands	ef0e9e4	2008-03-17 12:17:41 +0000	[diff] [blame]	877	<dd>This function attribute indicates that no exceptions unwind out of the
				878	function. Usually this is because the function makes no use of exceptions,
				879	but it may also be that the function catches any exceptions thrown when
				880	executing it.</dd>
				881
Duncan Sands	4ee4681	2007-07-27 19:57:41 +0000	[diff] [blame]	882	<dt><tt>nest</tt></dt>
Duncan Sands	f1a7d4c	2008-07-08 09:27:25 +0000	[diff] [blame]	883	<dd>This indicates that the pointer parameter can be excised using the
Duncan Sands	4ee4681	2007-07-27 19:57:41 +0000	[diff] [blame]	884	<a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sands	13e13f8	2007-11-22 20:23:04 +0000	[diff] [blame]	885	<dt><tt>readonly</tt></dt>
Duncan Sands	d69c0e6	2007-11-14 21:14:02 +0000	[diff] [blame]	886	<dd>This function attribute indicates that the function has no side-effects
Duncan Sands	13e13f8	2007-11-22 20:23:04 +0000	[diff] [blame]	887	except for producing a return value or throwing an exception. The value
				888	returned must only depend on the function arguments and/or global variables.
				889	It may use values obtained by dereferencing pointers.</dd>
				890	<dt><tt>readnone</tt></dt>
				891	<dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sands	d69c0e6	2007-11-14 21:14:02 +0000	[diff] [blame]	892	function, but in addition it is not allowed to dereference any pointer arguments
				893	or global variables.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	894	</dl>
				895
				896	</div>
				897
				898	<!-- ======================================================================= -->
				899	<div class="doc_subsection">
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	900	<a name="gc">Garbage Collector Names</a>
				901	</div>
				902
				903	<div class="doc_text">
				904	<p>Each function may specify a garbage collector name, which is simply a
				905	string.</p>
				906
				907	<div class="doc_code"><pre
				908	>define void @f() gc "name" { ...</pre></div>
				909
				910	<p>The compiler declares the supported values of <i>name</i>. Specifying a
				911	collector which will cause the compiler to alter its output in order to support
				912	the named garbage collection algorithm.</p>
				913	</div>
				914
				915	<!-- ======================================================================= -->
				916	<div class="doc_subsection">
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	917	<a name="notes">Function Notes</a>
				918	</div>
				919
				920	<div class="doc_text">
Devang Patel	25928cb	2008-09-04 23:10:26 +0000	[diff] [blame]	921	<p>The function definition may list function notes which are used by
				922	various passes.</p>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	923
				924	<div class="doc_code">
				925	<pre>define void @f() notes(inline=Always) { ... }</pre>
				926	<pre>define void @f() notes(inline=Always,opt-size) { ... }</pre>
				927	<pre>define void @f() notes(inline=Never,opt-size) { ... }</pre>
				928	<pre>define void @f() notes(opt-size) { ... }</pre>
				929	</div>
				930
				931	<p>
				932	<li>inline=Always
				933	<p>
				934	This note requests inliner to inline this function irrespective of
				935	inlining size threshold for this function.
				936	</p></li>
				937	<li>inline=Never
				938	<p>
				939	This note requests inliner to never inline this function in any situation.
				940	This note may not be used together with inline=Always note.
				941	</p></li>
				942	<li>opt-size
				943	<p>
				944	This note suggests optimization passes and code generator passes to make
				945	choices that help reduce code size.
				946	</p></li>
				947	<p>
				948	The notes that are not documented here are considered invalid notes.
				949	</div>
				950
				951	<!-- ======================================================================= -->
				952	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	953	<a name="moduleasm">Module-Level Inline Assembly</a>
				954	</div>
				955
				956	<div class="doc_text">
				957	<p>
				958	Modules may contain "module-level inline asm" blocks, which corresponds to the
				959	GCC "file scope inline asm" blocks. These blocks are internally concatenated by
				960	LLVM and treated as a single unit, but may be separated in the .ll file if
				961	desired. The syntax is very simple:
				962	</p>
				963
				964	<div class="doc_code">
				965	<pre>
				966	module asm "inline asm code goes here"
				967	module asm "more can go here"
				968	</pre>
				969	</div>
				970
				971	<p>The strings can contain any character by escaping non-printable characters.
				972	The escape sequence used is simply "\xx" where "xx" is the two digit hex code
				973	for the number.
				974	</p>
				975
				976	<p>
				977	The inline asm code is simply printed to the machine code .s file when
				978	assembly code is generated.
				979	</p>
				980	</div>
				981
				982	<!-- ======================================================================= -->
				983	<div class="doc_subsection">
				984	<a name="datalayout">Data Layout</a>
				985	</div>
				986
				987	<div class="doc_text">
				988	<p>A module may specify a target specific data layout string that specifies how
				989	data is to be laid out in memory. The syntax for the data layout is simply:</p>
				990	<pre> target datalayout = "<i>layout specification</i>"</pre>
				991	<p>The <i>layout specification</i> consists of a list of specifications
				992	separated by the minus sign character ('-'). Each specification starts with a
				993	letter and may include other information after the letter to define some
				994	aspect of the data layout. The specifications accepted are as follows: </p>
				995	<dl>
				996	<dt><tt>E</tt></dt>
				997	<dd>Specifies that the target lays out data in big-endian form. That is, the
				998	bits with the most significance have the lowest address location.</dd>
				999	<dt><tt>e</tt></dt>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1000	<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]	1001	the bits with the least significance have the lowest address location.</dd>
				1002	<dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1003	<dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
				1004	<i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
				1005	alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
				1006	too.</dd>
				1007	<dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1008	<dd>This specifies the alignment for an integer type of a given bit
				1009	<i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
				1010	<dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1011	<dd>This specifies the alignment for a vector type of a given bit
				1012	<i>size</i>.</dd>
				1013	<dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1014	<dd>This specifies the alignment for a floating point type of a given bit
				1015	<i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
				1016	(double).</dd>
				1017	<dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1018	<dd>This specifies the alignment for an aggregate type of a given bit
				1019	<i>size</i>.</dd>
				1020	</dl>
				1021	<p>When constructing the data layout for a given target, LLVM starts with a
				1022	default set of specifications which are then (possibly) overriden by the
				1023	specifications in the <tt>datalayout</tt> keyword. The default specifications
				1024	are given in this list:</p>
				1025	<ul>
				1026	<li><tt>E</tt> - big endian</li>
				1027	<li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
				1028	<li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
				1029	<li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
				1030	<li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
				1031	<li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1032	<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]	1033	alignment of 64-bits</li>
				1034	<li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
				1035	<li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
				1036	<li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
				1037	<li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
				1038	<li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
				1039	</ul>
Chris Lattner	6a9f3c4	2008-08-05 18:21:08 +0000	[diff] [blame]	1040	<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]	1041	following rules:
				1042	<ol>
				1043	<li>If the type sought is an exact match for one of the specifications, that
				1044	specification is used.</li>
				1045	<li>If no match is found, and the type sought is an integer type, then the
				1046	smallest integer type that is larger than the bitwidth of the sought type is
				1047	used. If none of the specifications are larger than the bitwidth then the the
				1048	largest integer type is used. For example, given the default specifications
				1049	above, the i7 type will use the alignment of i8 (next largest) while both
				1050	i65 and i256 will use the alignment of i64 (largest specified).</li>
				1051	<li>If no match is found, and the type sought is a vector type, then the
				1052	largest vector type that is smaller than the sought vector type will be used
				1053	as a fall back. This happens because <128 x double> can be implemented in
				1054	terms of 64 <2 x double>, for example.</li>
				1055	</ol>
				1056	</div>
				1057
				1058	<!-- *********************************************************************** -->
				1059	<div class="doc_section"> <a name="typesystem">Type System</a> </div>
				1060	<!-- *********************************************************************** -->
				1061
				1062	<div class="doc_text">
				1063
				1064	<p>The LLVM type system is one of the most important features of the
				1065	intermediate representation. Being typed enables a number of
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1066	optimizations to be performed on the intermediate representation directly,
				1067	without having to do
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1068	extra analyses on the side before the transformation. A strong type
				1069	system makes it easier to read the generated code and enables novel
				1070	analyses and transformations that are not feasible to perform on normal
				1071	three address code representations.</p>
				1072
				1073	</div>
				1074
				1075	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1076	<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1077	Classifications</a> </div>
				1078	<div class="doc_text">
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1079	<p>The types fall into a few useful
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1080	classifications:</p>
				1081
				1082	<table border="1" cellspacing="0" cellpadding="4">
				1083	<tbody>
				1084	<tr><th>Classification</th><th>Types</th></tr>
				1085	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1086	<td><a href="#t_integer">integer</a></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1087	<td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
				1088	</tr>
				1089	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1090	<td><a href="#t_floating">floating point</a></td>
				1091	<td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1092	</tr>
				1093	<tr>
				1094	<td><a name="t_firstclass">first class</a></td>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1095	<td><a href="#t_integer">integer</a>,
				1096	<a href="#t_floating">floating point</a>,
				1097	<a href="#t_pointer">pointer</a>,
Dan Gohman	f6237db	2008-06-18 18:42:13 +0000	[diff] [blame]	1098	<a href="#t_vector">vector</a>,
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	1099	<a href="#t_struct">structure</a>,
				1100	<a href="#t_array">array</a>,
Dan Gohman	d13951e	2008-05-23 22:50:26 +0000	[diff] [blame]	1101	<a href="#t_label">label</a>.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1102	</td>
				1103	</tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1104	<tr>
				1105	<td><a href="#t_primitive">primitive</a></td>
				1106	<td><a href="#t_label">label</a>,
				1107	<a href="#t_void">void</a>,
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1108	<a href="#t_floating">floating point</a>.</td>
				1109	</tr>
				1110	<tr>
				1111	<td><a href="#t_derived">derived</a></td>
				1112	<td><a href="#t_integer">integer</a>,
				1113	<a href="#t_array">array</a>,
				1114	<a href="#t_function">function</a>,
				1115	<a href="#t_pointer">pointer</a>,
				1116	<a href="#t_struct">structure</a>,
				1117	<a href="#t_pstruct">packed structure</a>,
				1118	<a href="#t_vector">vector</a>,
				1119	<a href="#t_opaque">opaque</a>.
				1120	</tr>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1121	</tbody>
				1122	</table>
				1123
				1124	<p>The <a href="#t_firstclass">first class</a> types are perhaps the
				1125	most important. Values of these types are the only ones which can be
				1126	produced by instructions, passed as arguments, or used as operands to
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	1127	instructions.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1128	</div>
				1129
				1130	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1131	<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1132
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1133	<div class="doc_text">
				1134	<p>The primitive types are the fundamental building blocks of the LLVM
				1135	system.</p>
				1136
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1137	</div>
				1138
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1139	<!-- _______________________________________________________________________ -->
				1140	<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
				1141
				1142	<div class="doc_text">
				1143	<table>
				1144	<tbody>
				1145	<tr><th>Type</th><th>Description</th></tr>
				1146	<tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
				1147	<tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
				1148	<tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
				1149	<tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
				1150	<tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
				1151	</tbody>
				1152	</table>
				1153	</div>
				1154
				1155	<!-- _______________________________________________________________________ -->
				1156	<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
				1157
				1158	<div class="doc_text">
				1159	<h5>Overview:</h5>
				1160	<p>The void type does not represent any value and has no size.</p>
				1161
				1162	<h5>Syntax:</h5>
				1163
				1164	<pre>
				1165	void
				1166	</pre>
				1167	</div>
				1168
				1169	<!-- _______________________________________________________________________ -->
				1170	<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
				1171
				1172	<div class="doc_text">
				1173	<h5>Overview:</h5>
				1174	<p>The label type represents code labels.</p>
				1175
				1176	<h5>Syntax:</h5>
				1177
				1178	<pre>
				1179	label
				1180	</pre>
				1181	</div>
				1182
				1183
				1184	<!-- ======================================================================= -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1185	<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
				1186
				1187	<div class="doc_text">
				1188
				1189	<p>The real power in LLVM comes from the derived types in the system.
				1190	This is what allows a programmer to represent arrays, functions,
				1191	pointers, and other useful types. Note that these derived types may be
				1192	recursive: For example, it is possible to have a two dimensional array.</p>
				1193
				1194	</div>
				1195
				1196	<!-- _______________________________________________________________________ -->
				1197	<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
				1198
				1199	<div class="doc_text">
				1200
				1201	<h5>Overview:</h5>
				1202	<p>The integer type is a very simple derived type that simply specifies an
				1203	arbitrary bit width for the integer type desired. Any bit width from 1 bit to
				1204	2^23-1 (about 8 million) can be specified.</p>
				1205
				1206	<h5>Syntax:</h5>
				1207
				1208	<pre>
				1209	iN
				1210	</pre>
				1211
				1212	<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
				1213	value.</p>
				1214
				1215	<h5>Examples:</h5>
				1216	<table class="layout">
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	1217	<tbody>
				1218	<tr>
				1219	<td><tt>i1</tt></td>
				1220	<td>a single-bit integer.</td>
				1221	</tr><tr>
				1222	<td><tt>i32</tt></td>
				1223	<td>a 32-bit integer.</td>
				1224	</tr><tr>
				1225	<td><tt>i1942652</tt></td>
				1226	<td>a really big integer of over 1 million bits.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1227	</tr>
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	1228	</tbody>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1229	</table>
				1230	</div>
				1231
				1232	<!-- _______________________________________________________________________ -->
				1233	<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
				1234
				1235	<div class="doc_text">
				1236
				1237	<h5>Overview:</h5>
				1238
				1239	<p>The array type is a very simple derived type that arranges elements
				1240	sequentially in memory. The array type requires a size (number of
				1241	elements) and an underlying data type.</p>
				1242
				1243	<h5>Syntax:</h5>
				1244
				1245	<pre>
				1246	[<# elements> x <elementtype>]
				1247	</pre>
				1248
				1249	<p>The number of elements is a constant integer value; elementtype may
				1250	be any type with a size.</p>
				1251
				1252	<h5>Examples:</h5>
				1253	<table class="layout">
				1254	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1255	<td class="left"><tt>[40 x i32]</tt></td>
				1256	<td class="left">Array of 40 32-bit integer values.</td>
				1257	</tr>
				1258	<tr class="layout">
				1259	<td class="left"><tt>[41 x i32]</tt></td>
				1260	<td class="left">Array of 41 32-bit integer values.</td>
				1261	</tr>
				1262	<tr class="layout">
				1263	<td class="left"><tt>[4 x i8]</tt></td>
				1264	<td class="left">Array of 4 8-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1265	</tr>
				1266	</table>
				1267	<p>Here are some examples of multidimensional arrays:</p>
				1268	<table class="layout">
				1269	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1270	<td class="left"><tt>[3 x [4 x i32]]</tt></td>
				1271	<td class="left">3x4 array of 32-bit integer values.</td>
				1272	</tr>
				1273	<tr class="layout">
				1274	<td class="left"><tt>[12 x [10 x float]]</tt></td>
				1275	<td class="left">12x10 array of single precision floating point values.</td>
				1276	</tr>
				1277	<tr class="layout">
				1278	<td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
				1279	<td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1280	</tr>
				1281	</table>
				1282
				1283	<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
				1284	length array. Normally, accesses past the end of an array are undefined in
				1285	LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
				1286	As a special case, however, zero length arrays are recognized to be variable
				1287	length. This allows implementation of 'pascal style arrays' with the LLVM
				1288	type "{ i32, [0 x float]}", for example.</p>
				1289
				1290	</div>
				1291
				1292	<!-- _______________________________________________________________________ -->
				1293	<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
				1294	<div class="doc_text">
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1295
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1296	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1297
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1298	<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]	1299	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]	1300	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]	1301	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]	1302	class types, and the struct must have at least one element.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1303
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1304	<h5>Syntax:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1305
				1306	<pre>
				1307	<returntype list> (<parameter list>)
				1308	</pre>
				1309
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1310	<p>...where '<tt><parameter list></tt>' is a comma-separated list of type
				1311	specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
				1312	which indicates that the function takes a variable number of arguments.
				1313	Variable argument functions can access their arguments with the <a
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1314	href="#int_varargs">variable argument handling intrinsic</a> functions.
				1315	'<tt><returntype list></tt>' is a comma-separated list of
				1316	<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1317
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1318	<h5>Examples:</h5>
				1319	<table class="layout">
				1320	<tr class="layout">
				1321	<td class="left"><tt>i32 (i32)</tt></td>
				1322	<td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
				1323	</td>
				1324	</tr><tr class="layout">
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	1325	<td class="left"><tt>float (i16 signext, i32 )
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1326	</tt></td>
				1327	<td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
				1328	an <tt>i16</tt> that should be sign extended and a
				1329	<a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
				1330	<tt>float</tt>.
				1331	</td>
				1332	</tr><tr class="layout">
				1333	<td class="left"><tt>i32 (i8*, ...)</tt></td>
				1334	<td class="left">A vararg function that takes at least one
				1335	<a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
				1336	which returns an integer. This is the signature for <tt>printf</tt> in
				1337	LLVM.
				1338	</td>
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1339	</tr><tr class="layout">
				1340	<td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel	6dddba2	2008-03-24 18:10:52 +0000	[diff] [blame]	1341	<td class="left">A function taking an <tt>i32></tt>, returning two
				1342	<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]	1343	</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1344	</tr>
				1345	</table>
				1346
				1347	</div>
				1348	<!-- _______________________________________________________________________ -->
				1349	<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
				1350	<div class="doc_text">
				1351	<h5>Overview:</h5>
				1352	<p>The structure type is used to represent a collection of data members
				1353	together in memory. The packing of the field types is defined to match
				1354	the ABI of the underlying processor. The elements of a structure may
				1355	be any type that has a size.</p>
				1356	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
				1357	and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
				1358	field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
				1359	instruction.</p>
				1360	<h5>Syntax:</h5>
				1361	<pre> { <type list> }<br></pre>
				1362	<h5>Examples:</h5>
				1363	<table class="layout">
				1364	<tr class="layout">
				1365	<td class="left"><tt>{ i32, i32, i32 }</tt></td>
				1366	<td class="left">A triple of three <tt>i32</tt> values</td>
				1367	</tr><tr class="layout">
				1368	<td class="left"><tt>{ float, i32 (i32) * }</tt></td>
				1369	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1370	second element is a <a href="#t_pointer">pointer</a> to a
				1371	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1372	an <tt>i32</tt>.</td>
				1373	</tr>
				1374	</table>
				1375	</div>
				1376
				1377	<!-- _______________________________________________________________________ -->
				1378	<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
				1379	</div>
				1380	<div class="doc_text">
				1381	<h5>Overview:</h5>
				1382	<p>The packed structure type is used to represent a collection of data members
				1383	together in memory. There is no padding between fields. Further, the alignment
				1384	of a packed structure is 1 byte. The elements of a packed structure may
				1385	be any type that has a size.</p>
				1386	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
				1387	and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
				1388	field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
				1389	instruction.</p>
				1390	<h5>Syntax:</h5>
				1391	<pre> < { <type list> } > <br></pre>
				1392	<h5>Examples:</h5>
				1393	<table class="layout">
				1394	<tr class="layout">
				1395	<td class="left"><tt>< { i32, i32, i32 } ></tt></td>
				1396	<td class="left">A triple of three <tt>i32</tt> values</td>
				1397	</tr><tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1398	<td class="left"><tt>< { float, i32 (i32)* } ></tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1399	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1400	second element is a <a href="#t_pointer">pointer</a> to a
				1401	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1402	an <tt>i32</tt>.</td>
				1403	</tr>
				1404	</table>
				1405	</div>
				1406
				1407	<!-- _______________________________________________________________________ -->
				1408	<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
				1409	<div class="doc_text">
				1410	<h5>Overview:</h5>
				1411	<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	1412	reference to another object, which must live in memory. Pointer types may have
				1413	an optional address space attribute defining the target-specific numbered
				1414	address space where the pointed-to object resides. The default address space is
				1415	zero.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1416	<h5>Syntax:</h5>
				1417	<pre> <type> *<br></pre>
				1418	<h5>Examples:</h5>
				1419	<table class="layout">
				1420	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1421	<td class="left"><tt>[4x i32]*</tt></td>
				1422	<td class="left">A <a href="#t_pointer">pointer</a> to <a
				1423	href="#t_array">array</a> of four <tt>i32</tt> values.</td>
				1424	</tr>
				1425	<tr class="layout">
				1426	<td class="left"><tt>i32 (i32 ) </tt></td>
				1427	<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]	1428	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]	1429	<tt>i32</tt>.</td>
				1430	</tr>
				1431	<tr class="layout">
				1432	<td class="left"><tt>i32 addrspace(5)*</tt></td>
				1433	<td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
				1434	that resides in address space #5.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1435	</tr>
				1436	</table>
				1437	</div>
				1438
				1439	<!-- _______________________________________________________________________ -->
				1440	<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
				1441	<div class="doc_text">
				1442
				1443	<h5>Overview:</h5>
				1444
				1445	<p>A vector type is a simple derived type that represents a vector
				1446	of elements. Vector types are used when multiple primitive data
				1447	are operated in parallel using a single instruction (SIMD).
				1448	A vector type requires a size (number of
				1449	elements) and an underlying primitive data type. Vectors must have a power
				1450	of two length (1, 2, 4, 8, 16 ...). Vector types are
				1451	considered <a href="#t_firstclass">first class</a>.</p>
				1452
				1453	<h5>Syntax:</h5>
				1454
				1455	<pre>
				1456	< <# elements> x <elementtype> >
				1457	</pre>
				1458
				1459	<p>The number of elements is a constant integer value; elementtype may
				1460	be any integer or floating point type.</p>
				1461
				1462	<h5>Examples:</h5>
				1463
				1464	<table class="layout">
				1465	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1466	<td class="left"><tt><4 x i32></tt></td>
				1467	<td class="left">Vector of 4 32-bit integer values.</td>
				1468	</tr>
				1469	<tr class="layout">
				1470	<td class="left"><tt><8 x float></tt></td>
				1471	<td class="left">Vector of 8 32-bit floating-point values.</td>
				1472	</tr>
				1473	<tr class="layout">
				1474	<td class="left"><tt><2 x i64></tt></td>
				1475	<td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1476	</tr>
				1477	</table>
				1478	</div>
				1479
				1480	<!-- _______________________________________________________________________ -->
				1481	<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
				1482	<div class="doc_text">
				1483
				1484	<h5>Overview:</h5>
				1485
				1486	<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]	1487	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]	1488	In LLVM, opaque types can eventually be resolved to any type (not just a
				1489	structure type).</p>
				1490
				1491	<h5>Syntax:</h5>
				1492
				1493	<pre>
				1494	opaque
				1495	</pre>
				1496
				1497	<h5>Examples:</h5>
				1498
				1499	<table class="layout">
				1500	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1501	<td class="left"><tt>opaque</tt></td>
				1502	<td class="left">An opaque type.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1503	</tr>
				1504	</table>
				1505	</div>
				1506
				1507
				1508	<!-- *********************************************************************** -->
				1509	<div class="doc_section"> <a name="constants">Constants</a> </div>
				1510	<!-- *********************************************************************** -->
				1511
				1512	<div class="doc_text">
				1513
				1514	<p>LLVM has several different basic types of constants. This section describes
				1515	them all and their syntax.</p>
				1516
				1517	</div>
				1518
				1519	<!-- ======================================================================= -->
				1520	<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
				1521
				1522	<div class="doc_text">
				1523
				1524	<dl>
				1525	<dt><b>Boolean constants</b></dt>
				1526
				1527	<dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
				1528	constants of the <tt><a href="#t_primitive">i1</a></tt> type.
				1529	</dd>
				1530
				1531	<dt><b>Integer constants</b></dt>
				1532
				1533	<dd>Standard integers (such as '4') are constants of the <a
				1534	href="#t_integer">integer</a> type. Negative numbers may be used with
				1535	integer types.
				1536	</dd>
				1537
				1538	<dt><b>Floating point constants</b></dt>
				1539
				1540	<dd>Floating point constants use standard decimal notation (e.g. 123.421),
				1541	exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	1542	notation (see below). The assembler requires the exact decimal value of
				1543	a floating-point constant. For example, the assembler accepts 1.25 but
				1544	rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
				1545	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]	1546
				1547	<dt><b>Null pointer constants</b></dt>
				1548
				1549	<dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
				1550	and must be of <a href="#t_pointer">pointer type</a>.</dd>
				1551
				1552	</dl>
				1553
				1554	<p>The one non-intuitive notation for constants is the optional hexadecimal form
				1555	of floating point constants. For example, the form '<tt>double
				1556	0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
				1557	4.5e+15</tt>'. The only time hexadecimal floating point constants are required
				1558	(and the only time that they are generated by the disassembler) is when a
				1559	floating point constant must be emitted but it cannot be represented as a
				1560	decimal floating point number. For example, NaN's, infinities, and other
				1561	special values are represented in their IEEE hexadecimal format so that
				1562	assembly and disassembly do not cause any bits to change in the constants.</p>
				1563
				1564	</div>
				1565
				1566	<!-- ======================================================================= -->
				1567	<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
				1568	</div>
				1569
				1570	<div class="doc_text">
				1571	<p>Aggregate constants arise from aggregation of simple constants
				1572	and smaller aggregate constants.</p>
				1573
				1574	<dl>
				1575	<dt><b>Structure constants</b></dt>
				1576
				1577	<dd>Structure constants are represented with notation similar to structure
				1578	type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner	6c8de96	2007-12-25 20:34:52 +0000	[diff] [blame]	1579	(<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
				1580	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]	1581	must have <a href="#t_struct">structure type</a>, and the number and
				1582	types of elements must match those specified by the type.
				1583	</dd>
				1584
				1585	<dt><b>Array constants</b></dt>
				1586
				1587	<dd>Array constants are represented with notation similar to array type
				1588	definitions (a comma separated list of elements, surrounded by square brackets
				1589	(<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
				1590	constants must have <a href="#t_array">array type</a>, and the number and
				1591	types of elements must match those specified by the type.
				1592	</dd>
				1593
				1594	<dt><b>Vector constants</b></dt>
				1595
				1596	<dd>Vector constants are represented with notation similar to vector type
				1597	definitions (a comma separated list of elements, surrounded by
				1598	less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32 42,
				1599	i32 11, i32 74, i32 100 ></tt>". Vector constants must have <a
				1600	href="#t_vector">vector type</a>, and the number and types of elements must
				1601	match those specified by the type.
				1602	</dd>
				1603
				1604	<dt><b>Zero initialization</b></dt>
				1605
				1606	<dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
				1607	value to zero of <em>any</em> type, including scalar and aggregate types.
				1608	This is often used to avoid having to print large zero initializers (e.g. for
				1609	large arrays) and is always exactly equivalent to using explicit zero
				1610	initializers.
				1611	</dd>
				1612	</dl>
				1613
				1614	</div>
				1615
				1616	<!-- ======================================================================= -->
				1617	<div class="doc_subsection">
				1618	<a name="globalconstants">Global Variable and Function Addresses</a>
				1619	</div>
				1620
				1621	<div class="doc_text">
				1622
				1623	<p>The addresses of <a href="#globalvars">global variables</a> and <a
				1624	href="#functionstructure">functions</a> are always implicitly valid (link-time)
				1625	constants. These constants are explicitly referenced when the <a
				1626	href="#identifiers">identifier for the global</a> is used and always have <a
				1627	href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
				1628	file:</p>
				1629
				1630	<div class="doc_code">
				1631	<pre>
				1632	@X = global i32 17
				1633	@Y = global i32 42
				1634	@Z = global [2 x i32] [ i32 @X, i32* @Y ]
				1635	</pre>
				1636	</div>
				1637
				1638	</div>
				1639
				1640	<!-- ======================================================================= -->
				1641	<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
				1642	<div class="doc_text">
				1643	<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
				1644	no specific value. Undefined values may be of any type and be used anywhere
				1645	a constant is permitted.</p>
				1646
				1647	<p>Undefined values indicate to the compiler that the program is well defined
				1648	no matter what value is used, giving the compiler more freedom to optimize.
				1649	</p>
				1650	</div>
				1651
				1652	<!-- ======================================================================= -->
				1653	<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
				1654	</div>
				1655
				1656	<div class="doc_text">
				1657
				1658	<p>Constant expressions are used to allow expressions involving other constants
				1659	to be used as constants. Constant expressions may be of any <a
				1660	href="#t_firstclass">first class</a> type and may involve any LLVM operation
				1661	that does not have side effects (e.g. load and call are not supported). The
				1662	following is the syntax for constant expressions:</p>
				1663
				1664	<dl>
				1665	<dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
				1666	<dd>Truncate a constant to another type. The bit size of CST must be larger
				1667	than the bit size of TYPE. Both types must be integers.</dd>
				1668
				1669	<dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
				1670	<dd>Zero extend a constant to another type. The bit size of CST must be
				1671	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1672
				1673	<dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
				1674	<dd>Sign extend a constant to another type. The bit size of CST must be
				1675	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1676
				1677	<dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
				1678	<dd>Truncate a floating point constant to another floating point type. The
				1679	size of CST must be larger than the size of TYPE. Both types must be
				1680	floating point.</dd>
				1681
				1682	<dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
				1683	<dd>Floating point extend a constant to another type. The size of CST must be
				1684	smaller or equal to the size of TYPE. Both types must be floating point.</dd>
				1685
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	1686	<dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1687	<dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1688	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1689	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1690	of the same number of elements. If the value won't fit in the integer type,
				1691	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1692
				1693	<dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
				1694	<dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1695	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1696	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1697	of the same number of elements. If the value won't fit in the integer type,
				1698	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1699
				1700	<dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
				1701	<dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1702	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1703	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1704	of the same number of elements. If the value won't fit in the floating point
				1705	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1706
				1707	<dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
				1708	<dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1709	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1710	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1711	of the same number of elements. If the value won't fit in the floating point
				1712	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1713
				1714	<dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
				1715	<dd>Convert a pointer typed constant to the corresponding integer constant
				1716	TYPE must be an integer type. CST must be of pointer type. The CST value is
				1717	zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
				1718
				1719	<dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
				1720	<dd>Convert a integer constant to a pointer constant. TYPE must be a
				1721	pointer type. CST must be of integer type. The CST value is zero extended,
				1722	truncated, or unchanged to make it fit in a pointer size. This one is
				1723	<i>really</i> dangerous!</dd>
				1724
				1725	<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
				1726	<dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
				1727	identical (same number of bits). The conversion is done as if the CST value
				1728	was stored to memory and read back as TYPE. In other words, no bits change
				1729	with this operator, just the type. This can be used for conversion of
				1730	vector types to any other type, as long as they have the same bit width. For
				1731	pointers it is only valid to cast to another pointer type.
				1732	</dd>
				1733
				1734	<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
				1735
				1736	<dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
				1737	constants. As with the <a href="#i_getelementptr">getelementptr</a>
				1738	instruction, the index list may have zero or more indexes, which are required
				1739	to make sense for the type of "CSTPTR".</dd>
				1740
				1741	<dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
				1742
				1743	<dd>Perform the <a href="#i_select">select operation</a> on
				1744	constants.</dd>
				1745
				1746	<dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
				1747	<dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
				1748
				1749	<dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1750	<dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
				1751
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	1752	<dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
				1753	<dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
				1754
				1755	<dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1756	<dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
				1757
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1758	<dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
				1759
				1760	<dd>Perform the <a href="#i_extractelement">extractelement
				1761	operation</a> on constants.
				1762
				1763	<dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
				1764
				1765	<dd>Perform the <a href="#i_insertelement">insertelement
				1766	operation</a> on constants.</dd>
				1767
				1768
				1769	<dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
				1770
				1771	<dd>Perform the <a href="#i_shufflevector">shufflevector
				1772	operation</a> on constants.</dd>
				1773
				1774	<dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
				1775
				1776	<dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
				1777	be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
				1778	binary</a> operations. The constraints on operands are the same as those for
				1779	the corresponding instruction (e.g. no bitwise operations on floating point
				1780	values are allowed).</dd>
				1781	</dl>
				1782	</div>
				1783
				1784	<!-- *********************************************************************** -->
				1785	<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
				1786	<!-- *********************************************************************** -->
				1787
				1788	<!-- ======================================================================= -->
				1789	<div class="doc_subsection">
				1790	<a name="inlineasm">Inline Assembler Expressions</a>
				1791	</div>
				1792
				1793	<div class="doc_text">
				1794
				1795	<p>
				1796	LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
				1797	Module-Level Inline Assembly</a>) through the use of a special value. This
				1798	value represents the inline assembler as a string (containing the instructions
				1799	to emit), a list of operand constraints (stored as a string), and a flag that
				1800	indicates whether or not the inline asm expression has side effects. An example
				1801	inline assembler expression is:
				1802	</p>
				1803
				1804	<div class="doc_code">
				1805	<pre>
				1806	i32 (i32) asm "bswap $0", "=r,r"
				1807	</pre>
				1808	</div>
				1809
				1810	<p>
				1811	Inline assembler expressions may <b>only</b> be used as the callee operand of
				1812	a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
				1813	</p>
				1814
				1815	<div class="doc_code">
				1816	<pre>
				1817	%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
				1818	</pre>
				1819	</div>
				1820
				1821	<p>
				1822	Inline asms with side effects not visible in the constraint list must be marked
				1823	as having side effects. This is done through the use of the
				1824	'<tt>sideeffect</tt>' keyword, like so:
				1825	</p>
				1826
				1827	<div class="doc_code">
				1828	<pre>
				1829	call void asm sideeffect "eieio", ""()
				1830	</pre>
				1831	</div>
				1832
				1833	<p>TODO: The format of the asm and constraints string still need to be
				1834	documented here. Constraints on what can be done (e.g. duplication, moving, etc
				1835	need to be documented).
				1836	</p>
				1837
				1838	</div>
				1839
				1840	<!-- *********************************************************************** -->
				1841	<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
				1842	<!-- *********************************************************************** -->
				1843
				1844	<div class="doc_text">
				1845
				1846	<p>The LLVM instruction set consists of several different
				1847	classifications of instructions: <a href="#terminators">terminator
				1848	instructions</a>, <a href="#binaryops">binary instructions</a>,
				1849	<a href="#bitwiseops">bitwise binary instructions</a>, <a
				1850	href="#memoryops">memory instructions</a>, and <a href="#otherops">other
				1851	instructions</a>.</p>
				1852
				1853	</div>
				1854
				1855	<!-- ======================================================================= -->
				1856	<div class="doc_subsection"> <a name="terminators">Terminator
				1857	Instructions</a> </div>
				1858
				1859	<div class="doc_text">
				1860
				1861	<p>As mentioned <a href="#functionstructure">previously</a>, every
				1862	basic block in a program ends with a "Terminator" instruction, which
				1863	indicates which block should be executed after the current block is
				1864	finished. These terminator instructions typically yield a '<tt>void</tt>'
				1865	value: they produce control flow, not values (the one exception being
				1866	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
				1867	<p>There are six different terminator instructions: the '<a
				1868	href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
				1869	instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
				1870	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
				1871	href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
				1872	href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
				1873
				1874	</div>
				1875
				1876	<!-- _______________________________________________________________________ -->
				1877	<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
				1878	Instruction</a> </div>
				1879	<div class="doc_text">
				1880	<h5>Syntax:</h5>
				1881	<pre> ret <type> <value> <i>; Return a value from a non-void function</i>
				1882	ret void <i>; Return from void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1883	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]	1884	</pre>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1885
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1886	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1887
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1888	<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
				1889	value) from a function back to the caller.</p>
				1890	<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]	1891	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]	1892	control flow to occur.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1893
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1894	<h5>Arguments:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1895
				1896	<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
				1897	The type of each return value must be a '<a href="#t_firstclass">first
				1898	class</a>' type. Note that a function is not <a href="#wellformed">well
				1899	formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
				1900	function that returns values that do not match the return type of the
				1901	function.</p>
				1902
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1903	<h5>Semantics:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1904
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1905	<p>When the '<tt>ret</tt>' instruction is executed, control flow
				1906	returns back to the calling function's context. If the caller is a "<a
				1907	href="#i_call"><tt>call</tt></a>" instruction, execution continues at
				1908	the instruction after the call. If the caller was an "<a
				1909	href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
				1910	at the beginning of the "normal" destination block. If the instruction
				1911	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]	1912	return value. If the instruction returns multiple values then these
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	1913	values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
				1914	</a>' instruction.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1915
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1916	<h5>Example:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1917
				1918	<pre>
				1919	ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1920	ret void <i>; Return from a void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1921	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]	1922	</pre>
				1923	</div>
				1924	<!-- _______________________________________________________________________ -->
				1925	<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
				1926	<div class="doc_text">
				1927	<h5>Syntax:</h5>
				1928	<pre> br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
				1929	</pre>
				1930	<h5>Overview:</h5>
				1931	<p>The '<tt>br</tt>' instruction is used to cause control flow to
				1932	transfer to a different basic block in the current function. There are
				1933	two forms of this instruction, corresponding to a conditional branch
				1934	and an unconditional branch.</p>
				1935	<h5>Arguments:</h5>
				1936	<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
				1937	single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
				1938	unconditional form of the '<tt>br</tt>' instruction takes a single
				1939	'<tt>label</tt>' value as a target.</p>
				1940	<h5>Semantics:</h5>
				1941	<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
				1942	argument is evaluated. If the value is <tt>true</tt>, control flows
				1943	to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
				1944	control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
				1945	<h5>Example:</h5>
				1946	<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
				1947	href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
				1948	</div>
				1949	<!-- _______________________________________________________________________ -->
				1950	<div class="doc_subsubsection">
				1951	<a name="i_switch">'<tt>switch</tt>' Instruction</a>
				1952	</div>
				1953
				1954	<div class="doc_text">
				1955	<h5>Syntax:</h5>
				1956
				1957	<pre>
				1958	switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
				1959	</pre>
				1960
				1961	<h5>Overview:</h5>
				1962
				1963	<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
				1964	several different places. It is a generalization of the '<tt>br</tt>'
				1965	instruction, allowing a branch to occur to one of many possible
				1966	destinations.</p>
				1967
				1968
				1969	<h5>Arguments:</h5>
				1970
				1971	<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
				1972	comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
				1973	an array of pairs of comparison value constants and '<tt>label</tt>'s. The
				1974	table is not allowed to contain duplicate constant entries.</p>
				1975
				1976	<h5>Semantics:</h5>
				1977
				1978	<p>The <tt>switch</tt> instruction specifies a table of values and
				1979	destinations. When the '<tt>switch</tt>' instruction is executed, this
				1980	table is searched for the given value. If the value is found, control flow is
				1981	transfered to the corresponding destination; otherwise, control flow is
				1982	transfered to the default destination.</p>
				1983
				1984	<h5>Implementation:</h5>
				1985
				1986	<p>Depending on properties of the target machine and the particular
				1987	<tt>switch</tt> instruction, this instruction may be code generated in different
				1988	ways. For example, it could be generated as a series of chained conditional
				1989	branches or with a lookup table.</p>
				1990
				1991	<h5>Example:</h5>
				1992
				1993	<pre>
				1994	<i>; Emulate a conditional br instruction</i>
				1995	%Val = <a href="#i_zext">zext</a> i1 %value to i32
				1996	switch i32 %Val, label %truedest [i32 0, label %falsedest ]
				1997
				1998	<i>; Emulate an unconditional br instruction</i>
				1999	switch i32 0, label %dest [ ]
				2000
				2001	<i>; Implement a jump table:</i>
				2002	switch i32 %val, label %otherwise [ i32 0, label %onzero
				2003	i32 1, label %onone
				2004	i32 2, label %ontwo ]
				2005	</pre>
				2006	</div>
				2007
				2008	<!-- _______________________________________________________________________ -->
				2009	<div class="doc_subsubsection">
				2010	<a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
				2011	</div>
				2012
				2013	<div class="doc_text">
				2014
				2015	<h5>Syntax:</h5>
				2016
				2017	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2018	<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]	2019	to label <normal label> unwind label <exception label>
				2020	</pre>
				2021
				2022	<h5>Overview:</h5>
				2023
				2024	<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
				2025	function, with the possibility of control flow transfer to either the
				2026	'<tt>normal</tt>' label or the
				2027	'<tt>exception</tt>' label. If the callee function returns with the
				2028	"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
				2029	"normal" label. If the callee (or any indirect callees) returns with the "<a
				2030	href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	2031	continued at the dynamically nearest "exception" label. If the callee function
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	2032	returns multiple values then individual return values are only accessible through
				2033	a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2034
				2035	<h5>Arguments:</h5>
				2036
				2037	<p>This instruction requires several arguments:</p>
				2038
				2039	<ol>
				2040	<li>
				2041	The optional "cconv" marker indicates which <a href="#callingconv">calling
				2042	convention</a> the call should use. If none is specified, the call defaults
				2043	to using C calling conventions.
				2044	</li>
				2045	<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
				2046	function value being invoked. In most cases, this is a direct function
				2047	invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
				2048	an arbitrary pointer to function value.
				2049	</li>
				2050
				2051	<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
				2052	function to be invoked. </li>
				2053
				2054	<li>'<tt>function args</tt>': argument list whose types match the function
				2055	signature argument types. If the function signature indicates the function
				2056	accepts a variable number of arguments, the extra arguments can be
				2057	specified. </li>
				2058
				2059	<li>'<tt>normal label</tt>': the label reached when the called function
				2060	executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
				2061
				2062	<li>'<tt>exception label</tt>': the label reached when a callee returns with
				2063	the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
				2064
				2065	</ol>
				2066
				2067	<h5>Semantics:</h5>
				2068
				2069	<p>This instruction is designed to operate as a standard '<tt><a
				2070	href="#i_call">call</a></tt>' instruction in most regards. The primary
				2071	difference is that it establishes an association with a label, which is used by
				2072	the runtime library to unwind the stack.</p>
				2073
				2074	<p>This instruction is used in languages with destructors to ensure that proper
				2075	cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
				2076	exception. Additionally, this is important for implementation of
				2077	'<tt>catch</tt>' clauses in high-level languages that support them.</p>
				2078
				2079	<h5>Example:</h5>
				2080	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2081	%retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2082	unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2083	%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]	2084	unwind label %TestCleanup <i>; {i32}:retval set</i>
				2085	</pre>
				2086	</div>
				2087
				2088
				2089	<!-- _______________________________________________________________________ -->
				2090
				2091	<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
				2092	Instruction</a> </div>
				2093
				2094	<div class="doc_text">
				2095
				2096	<h5>Syntax:</h5>
				2097	<pre>
				2098	unwind
				2099	</pre>
				2100
				2101	<h5>Overview:</h5>
				2102
				2103	<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
				2104	at the first callee in the dynamic call stack which used an <a
				2105	href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
				2106	primarily used to implement exception handling.</p>
				2107
				2108	<h5>Semantics:</h5>
				2109
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	2110	<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]	2111	immediately halt. The dynamic call stack is then searched for the first <a
				2112	href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
				2113	execution continues at the "exceptional" destination block specified by the
				2114	<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
				2115	dynamic call chain, undefined behavior results.</p>
				2116	</div>
				2117
				2118	<!-- _______________________________________________________________________ -->
				2119
				2120	<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
				2121	Instruction</a> </div>
				2122
				2123	<div class="doc_text">
				2124
				2125	<h5>Syntax:</h5>
				2126	<pre>
				2127	unreachable
				2128	</pre>
				2129
				2130	<h5>Overview:</h5>
				2131
				2132	<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
				2133	instruction is used to inform the optimizer that a particular portion of the
				2134	code is not reachable. This can be used to indicate that the code after a
				2135	no-return function cannot be reached, and other facts.</p>
				2136
				2137	<h5>Semantics:</h5>
				2138
				2139	<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
				2140	</div>
				2141
				2142
				2143
				2144	<!-- ======================================================================= -->
				2145	<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
				2146	<div class="doc_text">
				2147	<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]	2148	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]	2149	produce a single value. The operands might represent
				2150	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]	2151	The result value has the same type as its operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2152	<p>There are several different binary operators:</p>
				2153	</div>
				2154	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2155	<div class="doc_subsubsection">
				2156	<a name="i_add">'<tt>add</tt>' Instruction</a>
				2157	</div>
				2158
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2159	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2160
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2161	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2162
				2163	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2164	<result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2165	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2166
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2167	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2168
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2169	<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]	2170
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2171	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2172
				2173	<p>The two arguments to the '<tt>add</tt>' instruction must be <a
				2174	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
				2175	<a href="#t_vector">vector</a> values. Both arguments must have identical
				2176	types.</p>
				2177
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2178	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2179
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2180	<p>The value produced is the integer or floating point sum of the two
				2181	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2182
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2183	<p>If an integer sum has unsigned overflow, the result returned is the
				2184	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2185	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2186
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2187	<p>Because LLVM integers use a two's complement representation, this
				2188	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2189
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2190	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2191
				2192	<pre>
				2193	<result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2194	</pre>
				2195	</div>
				2196	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2197	<div class="doc_subsubsection">
				2198	<a name="i_sub">'<tt>sub</tt>' Instruction</a>
				2199	</div>
				2200
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2201	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2202
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2203	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2204
				2205	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2206	<result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2207	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2208
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2209	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2210
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2211	<p>The '<tt>sub</tt>' instruction returns the difference of its two
				2212	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2213
				2214	<p>Note that the '<tt>sub</tt>' instruction is used to represent the
				2215	'<tt>neg</tt>' instruction present in most other intermediate
				2216	representations.</p>
				2217
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2218	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2219
				2220	<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
				2221	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2222	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2223	types.</p>
				2224
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2225	<h5>Semantics:</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 value produced is the integer or floating point difference of
				2228	the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2229
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2230	<p>If an integer difference has unsigned overflow, the result returned is the
				2231	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2232	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2233
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2234	<p>Because LLVM integers use a two's complement representation, this
				2235	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2236
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2237	<h5>Example:</h5>
				2238	<pre>
				2239	<result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
				2240	<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
				2241	</pre>
				2242	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2243
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2244	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2245	<div class="doc_subsubsection">
				2246	<a name="i_mul">'<tt>mul</tt>' Instruction</a>
				2247	</div>
				2248
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2249	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2250
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2251	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2252	<pre> <result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2253	</pre>
				2254	<h5>Overview:</h5>
				2255	<p>The '<tt>mul</tt>' instruction returns the product of its two
				2256	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2257
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2258	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2259
				2260	<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
				2261	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2262	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2263	types.</p>
				2264
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2265	<h5>Semantics:</h5>
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	<p>The value produced is the integer or floating point product of the
				2268	two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2269
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2270	<p>If the result of an integer multiplication has unsigned overflow,
				2271	the result returned is the mathematical result modulo
				2272	2<sup>n</sup>, where n is the bit width of the result.</p>
				2273	<p>Because LLVM integers use a two's complement representation, and the
				2274	result is the same width as the operands, this instruction returns the
				2275	correct result for both signed and unsigned integers. If a full product
				2276	(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
				2277	should be sign-extended or zero-extended as appropriate to the
				2278	width of the full product.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2279	<h5>Example:</h5>
				2280	<pre> <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
				2281	</pre>
				2282	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2283
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2284	<!-- _______________________________________________________________________ -->
				2285	<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
				2286	</a></div>
				2287	<div class="doc_text">
				2288	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2289	<pre> <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2290	</pre>
				2291	<h5>Overview:</h5>
				2292	<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
				2293	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2294
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2295	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2296
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2297	<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2298	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2299	values. Both arguments must have identical types.</p>
				2300
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2301	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2302
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2303	<p>The value produced is the unsigned integer quotient of the two operands.</p>
				2304	<p>Note that unsigned integer division and signed integer division are distinct
				2305	operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
				2306	<p>Division by zero leads to undefined behavior.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2307	<h5>Example:</h5>
				2308	<pre> <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2309	</pre>
				2310	</div>
				2311	<!-- _______________________________________________________________________ -->
				2312	<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
				2313	</a> </div>
				2314	<div class="doc_text">
				2315	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2316	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2317	<result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2318	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2319
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2320	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2321
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2322	<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
				2323	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2324
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2325	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2326
				2327	<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
				2328	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2329	values. Both arguments must have identical types.</p>
				2330
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2331	<h5>Semantics:</h5>
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2332	<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]	2333	<p>Note that signed integer division and unsigned integer division are distinct
				2334	operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
				2335	<p>Division by zero leads to undefined behavior. Overflow also leads to
				2336	undefined behavior; this is a rare case, but can occur, for example,
				2337	by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2338	<h5>Example:</h5>
				2339	<pre> <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2340	</pre>
				2341	</div>
				2342	<!-- _______________________________________________________________________ -->
				2343	<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
				2344	Instruction</a> </div>
				2345	<div class="doc_text">
				2346	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2347	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2348	<result> = fdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2349	</pre>
				2350	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2351
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2352	<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
				2353	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2354
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2355	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2356
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2357	<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2358	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2359	of floating point values. Both arguments must have identical types.</p>
				2360
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2361	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2362
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2363	<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]	2364
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2365	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2366
				2367	<pre>
				2368	<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]	2369	</pre>
				2370	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2371
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2372	<!-- _______________________________________________________________________ -->
				2373	<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
				2374	</div>
				2375	<div class="doc_text">
				2376	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2377	<pre> <result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2378	</pre>
				2379	<h5>Overview:</h5>
				2380	<p>The '<tt>urem</tt>' instruction returns the remainder from the
				2381	unsigned division of its two arguments.</p>
				2382	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2383	<p>The two arguments to the '<tt>urem</tt>' instruction must be
				2384	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2385	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2386	<h5>Semantics:</h5>
				2387	<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]	2388	This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2389	<p>Note that unsigned integer remainder and signed integer remainder are
				2390	distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
				2391	<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]	2392	<h5>Example:</h5>
				2393	<pre> <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2394	</pre>
				2395
				2396	</div>
				2397	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2398	<div class="doc_subsubsection">
				2399	<a name="i_srem">'<tt>srem</tt>' Instruction</a>
				2400	</div>
				2401
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2402	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2403
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2404	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2405
				2406	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2407	<result> = srem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2408	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2409
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2410	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2411
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2412	<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman	3e3fd8c	2007-11-05 23:35:22 +0000	[diff] [blame]	2413	signed division of its two operands. This instruction can also take
				2414	<a href="#t_vector">vector</a> versions of the values in which case
				2415	the elements must be integers.</p>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	2416
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2417	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2418
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2419	<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2420	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2421	values. Both arguments must have identical types.</p>
				2422
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2423	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2424
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2425	<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]	2426	has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
				2427	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]	2428	a value. For more information about the difference, see <a
				2429	href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
				2430	Math Forum</a>. For a table of how this is implemented in various languages,
				2431	please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
				2432	Wikipedia: modulo operation</a>.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2433	<p>Note that signed integer remainder and unsigned integer remainder are
				2434	distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
				2435	<p>Taking the remainder of a division by zero leads to undefined behavior.
				2436	Overflow also leads to undefined behavior; this is a rare case, but can occur,
				2437	for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
				2438	(The remainder doesn't actually overflow, but this rule lets srem be
				2439	implemented using instructions that return both the result of the division
				2440	and the remainder.)</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2441	<h5>Example:</h5>
				2442	<pre> <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2443	</pre>
				2444
				2445	</div>
				2446	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2447	<div class="doc_subsubsection">
				2448	<a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
				2449
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2450	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2451
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2452	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2453	<pre> <result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2454	</pre>
				2455	<h5>Overview:</h5>
				2456	<p>The '<tt>frem</tt>' instruction returns the remainder from the
				2457	division of its two operands.</p>
				2458	<h5>Arguments:</h5>
				2459	<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2460	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2461	of floating point values. Both arguments must have identical types.</p>
				2462
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2463	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2464
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2465	<p>This instruction returns the <i>remainder</i> of a division.
				2466	The remainder has the same sign as the dividend.</p>
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>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2469
				2470	<pre>
				2471	<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]	2472	</pre>
				2473	</div>
				2474
				2475	<!-- ======================================================================= -->
				2476	<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
				2477	Operations</a> </div>
				2478	<div class="doc_text">
				2479	<p>Bitwise binary operators are used to do various forms of
				2480	bit-twiddling in a program. They are generally very efficient
				2481	instructions and can commonly be strength reduced from other
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2482	instructions. They require two operands of the same type, execute an operation on them,
				2483	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]	2484	</div>
				2485
				2486	<!-- _______________________________________________________________________ -->
				2487	<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
				2488	Instruction</a> </div>
				2489	<div class="doc_text">
				2490	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2491	<pre> <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2492	</pre>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2493
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2494	<h5>Overview:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2495
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2496	<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
				2497	the left a specified number of bits.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2498
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2499	<h5>Arguments:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2500
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2501	<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]	2502	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]	2503	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2504
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2505	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2506
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2507	<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
				2508	where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
				2509	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]	2510
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2511	<h5>Example:</h5><pre>
				2512	<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
				2513	<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
				2514	<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2515	<result> = shl i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2516	</pre>
				2517	</div>
				2518	<!-- _______________________________________________________________________ -->
				2519	<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
				2520	Instruction</a> </div>
				2521	<div class="doc_text">
				2522	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2523	<pre> <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2524	</pre>
				2525
				2526	<h5>Overview:</h5>
				2527	<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
				2528	operand shifted to the right a specified number of bits with zero fill.</p>
				2529
				2530	<h5>Arguments:</h5>
				2531	<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]	2532	<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]	2533	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2534
				2535	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2536
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2537	<p>This instruction always performs a logical shift right operation. The most
				2538	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]	2539	shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
				2540	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]	2541
				2542	<h5>Example:</h5>
				2543	<pre>
				2544	<result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2545	<result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2546	<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2547	<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2548	<result> = lshr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2549	</pre>
				2550	</div>
				2551
				2552	<!-- _______________________________________________________________________ -->
				2553	<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
				2554	Instruction</a> </div>
				2555	<div class="doc_text">
				2556
				2557	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2558	<pre> <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2559	</pre>
				2560
				2561	<h5>Overview:</h5>
				2562	<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
				2563	operand shifted to the right a specified number of bits with sign extension.</p>
				2564
				2565	<h5>Arguments:</h5>
				2566	<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]	2567	<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]	2568	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2569
				2570	<h5>Semantics:</h5>
				2571	<p>This instruction always performs an arithmetic shift right operation,
				2572	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]	2573	of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
				2574	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]	2575	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2576
				2577	<h5>Example:</h5>
				2578	<pre>
				2579	<result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2580	<result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2581	<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2582	<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2583	<result> = ashr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2584	</pre>
				2585	</div>
				2586
				2587	<!-- _______________________________________________________________________ -->
				2588	<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
				2589	Instruction</a> </div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2590
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2591	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2592
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2593	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2594
				2595	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2596	<result> = and <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2597	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2598
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2599	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2600
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2601	<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
				2602	its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2603
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2604	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2605
				2606	<p>The two arguments to the '<tt>and</tt>' instruction must be
				2607	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2608	values. Both arguments must have identical types.</p>
				2609
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2610	<h5>Semantics:</h5>
				2611	<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
				2612	<p> </p>
				2613	<div style="align: center">
				2614	<table border="1" cellspacing="0" cellpadding="4">
				2615	<tbody>
				2616	<tr>
				2617	<td>In0</td>
				2618	<td>In1</td>
				2619	<td>Out</td>
				2620	</tr>
				2621	<tr>
				2622	<td>0</td>
				2623	<td>0</td>
				2624	<td>0</td>
				2625	</tr>
				2626	<tr>
				2627	<td>0</td>
				2628	<td>1</td>
				2629	<td>0</td>
				2630	</tr>
				2631	<tr>
				2632	<td>1</td>
				2633	<td>0</td>
				2634	<td>0</td>
				2635	</tr>
				2636	<tr>
				2637	<td>1</td>
				2638	<td>1</td>
				2639	<td>1</td>
				2640	</tr>
				2641	</tbody>
				2642	</table>
				2643	</div>
				2644	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2645	<pre>
				2646	<result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2647	<result> = and i32 15, 40 <i>; yields {i32}:result = 8</i>
				2648	<result> = and i32 4, 8 <i>; yields {i32}:result = 0</i>
				2649	</pre>
				2650	</div>
				2651	<!-- _______________________________________________________________________ -->
				2652	<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
				2653	<div class="doc_text">
				2654	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2655	<pre> <result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2656	</pre>
				2657	<h5>Overview:</h5>
				2658	<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
				2659	or of its two operands.</p>
				2660	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2661
				2662	<p>The two arguments to the '<tt>or</tt>' instruction must be
				2663	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2664	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2665	<h5>Semantics:</h5>
				2666	<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
				2667	<p> </p>
				2668	<div style="align: center">
				2669	<table border="1" cellspacing="0" cellpadding="4">
				2670	<tbody>
				2671	<tr>
				2672	<td>In0</td>
				2673	<td>In1</td>
				2674	<td>Out</td>
				2675	</tr>
				2676	<tr>
				2677	<td>0</td>
				2678	<td>0</td>
				2679	<td>0</td>
				2680	</tr>
				2681	<tr>
				2682	<td>0</td>
				2683	<td>1</td>
				2684	<td>1</td>
				2685	</tr>
				2686	<tr>
				2687	<td>1</td>
				2688	<td>0</td>
				2689	<td>1</td>
				2690	</tr>
				2691	<tr>
				2692	<td>1</td>
				2693	<td>1</td>
				2694	<td>1</td>
				2695	</tr>
				2696	</tbody>
				2697	</table>
				2698	</div>
				2699	<h5>Example:</h5>
				2700	<pre> <result> = or i32 4, %var <i>; yields {i32}:result = 4 \| %var</i>
				2701	<result> = or i32 15, 40 <i>; yields {i32}:result = 47</i>
				2702	<result> = or i32 4, 8 <i>; yields {i32}:result = 12</i>
				2703	</pre>
				2704	</div>
				2705	<!-- _______________________________________________________________________ -->
				2706	<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
				2707	Instruction</a> </div>
				2708	<div class="doc_text">
				2709	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2710	<pre> <result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2711	</pre>
				2712	<h5>Overview:</h5>
				2713	<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
				2714	or of its two operands. The <tt>xor</tt> is used to implement the
				2715	"one's complement" operation, which is the "~" operator in C.</p>
				2716	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2717	<p>The two arguments to the '<tt>xor</tt>' instruction must be
				2718	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2719	values. Both arguments must have identical types.</p>
				2720
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2721	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2722
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2723	<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
				2724	<p> </p>
				2725	<div style="align: center">
				2726	<table border="1" cellspacing="0" cellpadding="4">
				2727	<tbody>
				2728	<tr>
				2729	<td>In0</td>
				2730	<td>In1</td>
				2731	<td>Out</td>
				2732	</tr>
				2733	<tr>
				2734	<td>0</td>
				2735	<td>0</td>
				2736	<td>0</td>
				2737	</tr>
				2738	<tr>
				2739	<td>0</td>
				2740	<td>1</td>
				2741	<td>1</td>
				2742	</tr>
				2743	<tr>
				2744	<td>1</td>
				2745	<td>0</td>
				2746	<td>1</td>
				2747	</tr>
				2748	<tr>
				2749	<td>1</td>
				2750	<td>1</td>
				2751	<td>0</td>
				2752	</tr>
				2753	</tbody>
				2754	</table>
				2755	</div>
				2756	<p> </p>
				2757	<h5>Example:</h5>
				2758	<pre> <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
				2759	<result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
				2760	<result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
				2761	<result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
				2762	</pre>
				2763	</div>
				2764
				2765	<!-- ======================================================================= -->
				2766	<div class="doc_subsection">
				2767	<a name="vectorops">Vector Operations</a>
				2768	</div>
				2769
				2770	<div class="doc_text">
				2771
				2772	<p>LLVM supports several instructions to represent vector operations in a
				2773	target-independent manner. These instructions cover the element-access and
				2774	vector-specific operations needed to process vectors effectively. While LLVM
				2775	does directly support these vector operations, many sophisticated algorithms
				2776	will want to use target-specific intrinsics to take full advantage of a specific
				2777	target.</p>
				2778
				2779	</div>
				2780
				2781	<!-- _______________________________________________________________________ -->
				2782	<div class="doc_subsubsection">
				2783	<a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
				2784	</div>
				2785
				2786	<div class="doc_text">
				2787
				2788	<h5>Syntax:</h5>
				2789
				2790	<pre>
				2791	<result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
				2792	</pre>
				2793
				2794	<h5>Overview:</h5>
				2795
				2796	<p>
				2797	The '<tt>extractelement</tt>' instruction extracts a single scalar
				2798	element from a vector at a specified index.
				2799	</p>
				2800
				2801
				2802	<h5>Arguments:</h5>
				2803
				2804	<p>
				2805	The first operand of an '<tt>extractelement</tt>' instruction is a
				2806	value of <a href="#t_vector">vector</a> type. The second operand is
				2807	an index indicating the position from which to extract the element.
				2808	The index may be a variable.</p>
				2809
				2810	<h5>Semantics:</h5>
				2811
				2812	<p>
				2813	The result is a scalar of the same type as the element type of
				2814	<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
				2815	<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
				2816	results are undefined.
				2817	</p>
				2818
				2819	<h5>Example:</h5>
				2820
				2821	<pre>
				2822	%result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
				2823	</pre>
				2824	</div>
				2825
				2826
				2827	<!-- _______________________________________________________________________ -->
				2828	<div class="doc_subsubsection">
				2829	<a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
				2830	</div>
				2831
				2832	<div class="doc_text">
				2833
				2834	<h5>Syntax:</h5>
				2835
				2836	<pre>
Dan Gohman	bcc3c50	2008-05-12 23:38:42 +0000	[diff] [blame]	2837	<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]	2838	</pre>
				2839
				2840	<h5>Overview:</h5>
				2841
				2842	<p>
				2843	The '<tt>insertelement</tt>' instruction inserts a scalar
				2844	element into a vector at a specified index.
				2845	</p>
				2846
				2847
				2848	<h5>Arguments:</h5>
				2849
				2850	<p>
				2851	The first operand of an '<tt>insertelement</tt>' instruction is a
				2852	value of <a href="#t_vector">vector</a> type. The second operand is a
				2853	scalar value whose type must equal the element type of the first
				2854	operand. The third operand is an index indicating the position at
				2855	which to insert the value. The index may be a variable.</p>
				2856
				2857	<h5>Semantics:</h5>
				2858
				2859	<p>
				2860	The result is a vector of the same type as <tt>val</tt>. Its
				2861	element values are those of <tt>val</tt> except at position
				2862	<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
				2863	exceeds the length of <tt>val</tt>, the results are undefined.
				2864	</p>
				2865
				2866	<h5>Example:</h5>
				2867
				2868	<pre>
				2869	%result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
				2870	</pre>
				2871	</div>
				2872
				2873	<!-- _______________________________________________________________________ -->
				2874	<div class="doc_subsubsection">
				2875	<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
				2876	</div>
				2877
				2878	<div class="doc_text">
				2879
				2880	<h5>Syntax:</h5>
				2881
				2882	<pre>
				2883	<result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x i32> <mask> <i>; yields <n x <ty>></i>
				2884	</pre>
				2885
				2886	<h5>Overview:</h5>
				2887
				2888	<p>
				2889	The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
				2890	from two input vectors, returning a vector of the same type.
				2891	</p>
				2892
				2893	<h5>Arguments:</h5>
				2894
				2895	<p>
				2896	The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
				2897	with types that match each other and types that match the result of the
				2898	instruction. The third argument is a shuffle mask, which has the same number
				2899	of elements as the other vector type, but whose element type is always 'i32'.
				2900	</p>
				2901
				2902	<p>
				2903	The shuffle mask operand is required to be a constant vector with either
				2904	constant integer or undef values.
				2905	</p>
				2906
				2907	<h5>Semantics:</h5>
				2908
				2909	<p>
				2910	The elements of the two input vectors are numbered from left to right across
				2911	both of the vectors. The shuffle mask operand specifies, for each element of
				2912	the result vector, which element of the two input registers the result element
				2913	gets. The element selector may be undef (meaning "don't care") and the second
				2914	operand may be undef if performing a shuffle from only one vector.
				2915	</p>
				2916
				2917	<h5>Example:</h5>
				2918
				2919	<pre>
				2920	%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
				2921	<4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
				2922	%result = shufflevector <4 x i32> %v1, <4 x i32> undef,
				2923	<4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
				2924	</pre>
				2925	</div>
				2926
				2927
				2928	<!-- ======================================================================= -->
				2929	<div class="doc_subsection">
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2930	<a name="aggregateops">Aggregate Operations</a>
				2931	</div>
				2932
				2933	<div class="doc_text">
				2934
				2935	<p>LLVM supports several instructions for working with aggregate values.
				2936	</p>
				2937
				2938	</div>
				2939
				2940	<!-- _______________________________________________________________________ -->
				2941	<div class="doc_subsubsection">
				2942	<a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
				2943	</div>
				2944
				2945	<div class="doc_text">
				2946
				2947	<h5>Syntax:</h5>
				2948
				2949	<pre>
				2950	<result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
				2951	</pre>
				2952
				2953	<h5>Overview:</h5>
				2954
				2955	<p>
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	2956	The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
				2957	or array element from an aggregate value.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2958	</p>
				2959
				2960
				2961	<h5>Arguments:</h5>
				2962
				2963	<p>
				2964	The first operand of an '<tt>extractvalue</tt>' instruction is a
				2965	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]	2966	type. The operands are constant indices to specify which value to extract
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2967	in a similar manner as indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2968	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				2969	</p>
				2970
				2971	<h5>Semantics:</h5>
				2972
				2973	<p>
				2974	The result is the value at the position in the aggregate specified by
				2975	the index operands.
				2976	</p>
				2977
				2978	<h5>Example:</h5>
				2979
				2980	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2981	%result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2982	</pre>
				2983	</div>
				2984
				2985
				2986	<!-- _______________________________________________________________________ -->
				2987	<div class="doc_subsubsection">
				2988	<a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
				2989	</div>
				2990
				2991	<div class="doc_text">
				2992
				2993	<h5>Syntax:</h5>
				2994
				2995	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2996	<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]	2997	</pre>
				2998
				2999	<h5>Overview:</h5>
				3000
				3001	<p>
				3002	The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3003	into a struct field or array element in an aggregate.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3004	</p>
				3005
				3006
				3007	<h5>Arguments:</h5>
				3008
				3009	<p>
				3010	The first operand of an '<tt>insertvalue</tt>' instruction is a
				3011	value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
				3012	The second operand is a first-class value to insert.
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	3013	The following operands are constant indices
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3014	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]	3015	indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3016	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				3017	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]	3018	by the indices.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3019
				3020	<h5>Semantics:</h5>
				3021
				3022	<p>
				3023	The result is an aggregate of the same type as <tt>val</tt>. Its
				3024	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]	3025	specified by the indices is that of <tt>elt</tt>.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3026	</p>
				3027
				3028	<h5>Example:</h5>
				3029
				3030	<pre>
Dan Gohman	b1aab4e	2008-06-23 15:26:37 +0000	[diff] [blame]	3031	%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]	3032	</pre>
				3033	</div>
				3034
				3035
				3036	<!-- ======================================================================= -->
				3037	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3038	<a name="memoryops">Memory Access and Addressing Operations</a>
				3039	</div>
				3040
				3041	<div class="doc_text">
				3042
				3043	<p>A key design point of an SSA-based representation is how it
				3044	represents memory. In LLVM, no memory locations are in SSA form, which
				3045	makes things very simple. This section describes how to read, write,
				3046	allocate, and free memory in LLVM.</p>
				3047
				3048	</div>
				3049
				3050	<!-- _______________________________________________________________________ -->
				3051	<div class="doc_subsubsection">
				3052	<a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
				3053	</div>
				3054
				3055	<div class="doc_text">
				3056
				3057	<h5>Syntax:</h5>
				3058
				3059	<pre>
				3060	<result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3061	</pre>
				3062
				3063	<h5>Overview:</h5>
				3064
				3065	<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3066	heap and returns a pointer to it. The object is always allocated in the generic
				3067	address space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3068
				3069	<h5>Arguments:</h5>
				3070
				3071	<p>The '<tt>malloc</tt>' instruction allocates
				3072	<tt>sizeof(<type>)*NumElements</tt>
				3073	bytes of memory from the operating system and returns a pointer of the
				3074	appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3075	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3076	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]	3077	be aligned to at least that boundary. If not specified, or if zero, the target can
				3078	choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3079
				3080	<p>'<tt>type</tt>' must be a sized type.</p>
				3081
				3082	<h5>Semantics:</h5>
				3083
				3084	<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3085	a pointer is returned. The result of a zero byte allocattion is undefined. The
				3086	result is null if there is insufficient memory available.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3087
				3088	<h5>Example:</h5>
				3089
				3090	<pre>
				3091	%array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
				3092
				3093	%size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
				3094	%array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
				3095	%array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
				3096	%array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
				3097	%array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
				3098	</pre>
				3099	</div>
				3100
				3101	<!-- _______________________________________________________________________ -->
				3102	<div class="doc_subsubsection">
				3103	<a name="i_free">'<tt>free</tt>' Instruction</a>
				3104	</div>
				3105
				3106	<div class="doc_text">
				3107
				3108	<h5>Syntax:</h5>
				3109
				3110	<pre>
				3111	free <type> <value> <i>; yields {void}</i>
				3112	</pre>
				3113
				3114	<h5>Overview:</h5>
				3115
				3116	<p>The '<tt>free</tt>' instruction returns memory back to the unused
				3117	memory heap to be reallocated in the future.</p>
				3118
				3119	<h5>Arguments:</h5>
				3120
				3121	<p>'<tt>value</tt>' shall be a pointer value that points to a value
				3122	that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
				3123	instruction.</p>
				3124
				3125	<h5>Semantics:</h5>
				3126
				3127	<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]	3128	after this instruction executes. If the pointer is null, the operation
				3129	is a noop.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3130
				3131	<h5>Example:</h5>
				3132
				3133	<pre>
				3134	%array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
				3135	free [4 x i8]* %array
				3136	</pre>
				3137	</div>
				3138
				3139	<!-- _______________________________________________________________________ -->
				3140	<div class="doc_subsubsection">
				3141	<a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
				3142	</div>
				3143
				3144	<div class="doc_text">
				3145
				3146	<h5>Syntax:</h5>
				3147
				3148	<pre>
				3149	<result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3150	</pre>
				3151
				3152	<h5>Overview:</h5>
				3153
				3154	<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
				3155	currently executing function, to be automatically released when this function
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3156	returns to its caller. The object is always allocated in the generic address
				3157	space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3158
				3159	<h5>Arguments:</h5>
				3160
				3161	<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
				3162	bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3163	appropriate type to the program. If "NumElements" is specified, it is the
				3164	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3165	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]	3166	to be aligned to at least that boundary. If not specified, or if zero, the target
				3167	can choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3168
				3169	<p>'<tt>type</tt>' may be any sized type.</p>
				3170
				3171	<h5>Semantics:</h5>
				3172
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3173	<p>Memory is allocated; a pointer is returned. The operation is undefiend if
				3174	there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3175	memory is automatically released when the function returns. The '<tt>alloca</tt>'
				3176	instruction is commonly used to represent automatic variables that must
				3177	have an address available. When the function returns (either with the <tt><a
				3178	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]	3179	instructions), the memory is reclaimed. Allocating zero bytes
				3180	is legal, but the result is undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3181
				3182	<h5>Example:</h5>
				3183
				3184	<pre>
				3185	%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
				3186	%ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
				3187	%ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
				3188	%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
				3189	</pre>
				3190	</div>
				3191
				3192	<!-- _______________________________________________________________________ -->
				3193	<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
				3194	Instruction</a> </div>
				3195	<div class="doc_text">
				3196	<h5>Syntax:</h5>
				3197	<pre> <result> = load <ty>* <pointer>[, align <alignment>]<br> <result> = volatile load <ty>* <pointer>[, align <alignment>]<br></pre>
				3198	<h5>Overview:</h5>
				3199	<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
				3200	<h5>Arguments:</h5>
				3201	<p>The argument to the '<tt>load</tt>' instruction specifies the memory
				3202	address from which to load. The pointer must point to a <a
				3203	href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
				3204	marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
				3205	the number or order of execution of this <tt>load</tt> with other
				3206	volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
				3207	instructions. </p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3208	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3209	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3210	(that is, the alignment of the memory address). A value of 0 or an
				3211	omitted "align" argument means that the operation has the preferential
				3212	alignment for the target. It is the responsibility of the code emitter
				3213	to ensure that the alignment information is correct. Overestimating
				3214	the alignment results in an undefined behavior. Underestimating the
				3215	alignment may produce less efficient code. An alignment of 1 is always
				3216	safe.
				3217	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3218	<h5>Semantics:</h5>
				3219	<p>The location of memory pointed to is loaded.</p>
				3220	<h5>Examples:</h5>
				3221	<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
				3222	<a
				3223	href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
				3224	%val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
				3225	</pre>
				3226	</div>
				3227	<!-- _______________________________________________________________________ -->
				3228	<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
				3229	Instruction</a> </div>
				3230	<div class="doc_text">
				3231	<h5>Syntax:</h5>
				3232	<pre> store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3233	volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3234	</pre>
				3235	<h5>Overview:</h5>
				3236	<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
				3237	<h5>Arguments:</h5>
				3238	<p>There are two arguments to the '<tt>store</tt>' instruction: a value
				3239	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]	3240	operand must be a pointer to the <a href="#t_firstclass">first class</a> type
				3241	of the '<tt><value></tt>'
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3242	operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
				3243	optimizer is not allowed to modify the number or order of execution of
				3244	this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
				3245	href="#i_store">store</a></tt> instructions.</p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3246	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3247	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3248	(that is, the alignment of the memory address). A value of 0 or an
				3249	omitted "align" argument means that the operation has the preferential
				3250	alignment for the target. It is the responsibility of the code emitter
				3251	to ensure that the alignment information is correct. Overestimating
				3252	the alignment results in an undefined behavior. Underestimating the
				3253	alignment may produce less efficient code. An alignment of 1 is always
				3254	safe.
				3255	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3256	<h5>Semantics:</h5>
				3257	<p>The contents of memory are updated to contain '<tt><value></tt>'
				3258	at the location specified by the '<tt><pointer></tt>' operand.</p>
				3259	<h5>Example:</h5>
				3260	<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]	3261	store i32 3, i32* %ptr <i>; yields {void}</i>
				3262	%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]	3263	</pre>
				3264	</div>
				3265
				3266	<!-- _______________________________________________________________________ -->
				3267	<div class="doc_subsubsection">
				3268	<a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
				3269	</div>
				3270
				3271	<div class="doc_text">
				3272	<h5>Syntax:</h5>
				3273	<pre>
				3274	<result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}*
				3275	</pre>
				3276
				3277	<h5>Overview:</h5>
				3278
				3279	<p>
				3280	The '<tt>getelementptr</tt>' instruction is used to get the address of a
				3281	subelement of an aggregate data structure.</p>
				3282
				3283	<h5>Arguments:</h5>
				3284
				3285	<p>This instruction takes a list of integer operands that indicate what
				3286	elements of the aggregate object to index to. The actual types of the arguments
				3287	provided depend on the type of the first pointer argument. The
				3288	'<tt>getelementptr</tt>' instruction is used to index down through the type
				3289	levels of a structure or to a specific index in an array. When indexing into a
				3290	structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	3291	into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
				3292	values will be sign extended to 64-bits if required.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3293
				3294	<p>For example, let's consider a C code fragment and how it gets
				3295	compiled to LLVM:</p>
				3296
				3297	<div class="doc_code">
				3298	<pre>
				3299	struct RT {
				3300	char A;
				3301	int B[10][20];
				3302	char C;
				3303	};
				3304	struct ST {
				3305	int X;
				3306	double Y;
				3307	struct RT Z;
				3308	};
				3309
				3310	int foo(struct ST s) {
				3311	return &s[1].Z.B[5][13];
				3312	}
				3313	</pre>
				3314	</div>
				3315
				3316	<p>The LLVM code generated by the GCC frontend is:</p>
				3317
				3318	<div class="doc_code">
				3319	<pre>
				3320	%RT = type { i8 , [10 x [20 x i32]], i8 }
				3321	%ST = type { i32, double, %RT }
				3322
				3323	define i32* %foo(%ST* %s) {
				3324	entry:
				3325	%reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
				3326	ret i32* %reg
				3327	}
				3328	</pre>
				3329	</div>
				3330
				3331	<h5>Semantics:</h5>
				3332
				3333	<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
				3334	on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
				3335	and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
				3336	<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]	3337	to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
				3338	structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3339
				3340	<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
				3341	type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
				3342	}</tt>' type, a structure. The second index indexes into the third element of
				3343	the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
				3344	i8 }</tt>' type, another structure. The third index indexes into the second
				3345	element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
				3346	array. The two dimensions of the array are subscripted into, yielding an
				3347	'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
				3348	to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
				3349
				3350	<p>Note that it is perfectly legal to index partially through a
				3351	structure, returning a pointer to an inner element. Because of this,
				3352	the LLVM code for the given testcase is equivalent to:</p>
				3353
				3354	<pre>
				3355	define i32* %foo(%ST* %s) {
				3356	%t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
				3357	%t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
				3358	%t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
				3359	%t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
				3360	%t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
				3361	ret i32* %t5
				3362	}
				3363	</pre>
				3364
				3365	<p>Note that it is undefined to access an array out of bounds: array and
				3366	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]	3367	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]	3368	defined to be accessible as variable length arrays, which requires access
				3369	beyond the zero'th element.</p>
				3370
				3371	<p>The getelementptr instruction is often confusing. For some more insight
				3372	into how it works, see <a href="GetElementPtr.html">the getelementptr
				3373	FAQ</a>.</p>
				3374
				3375	<h5>Example:</h5>
				3376
				3377	<pre>
				3378	<i>; yields [12 x i8]*:aptr</i>
				3379	%aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
				3380	</pre>
				3381	</div>
				3382
				3383	<!-- ======================================================================= -->
				3384	<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
				3385	</div>
				3386	<div class="doc_text">
				3387	<p>The instructions in this category are the conversion instructions (casting)
				3388	which all take a single operand and a type. They perform various bit conversions
				3389	on the operand.</p>
				3390	</div>
				3391
				3392	<!-- _______________________________________________________________________ -->
				3393	<div class="doc_subsubsection">
				3394	<a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
				3395	</div>
				3396	<div class="doc_text">
				3397
				3398	<h5>Syntax:</h5>
				3399	<pre>
				3400	<result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3401	</pre>
				3402
				3403	<h5>Overview:</h5>
				3404	<p>
				3405	The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
				3406	</p>
				3407
				3408	<h5>Arguments:</h5>
				3409	<p>
				3410	The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
				3411	be an <a href="#t_integer">integer</a> type, and a type that specifies the size
				3412	and type of the result, which must be an <a href="#t_integer">integer</a>
				3413	type. The bit size of <tt>value</tt> must be larger than the bit size of
				3414	<tt>ty2</tt>. Equal sized types are not allowed.</p>
				3415
				3416	<h5>Semantics:</h5>
				3417	<p>
				3418	The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
				3419	and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
				3420	larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
				3421	It will always truncate bits.</p>
				3422
				3423	<h5>Example:</h5>
				3424	<pre>
				3425	%X = trunc i32 257 to i8 <i>; yields i8:1</i>
				3426	%Y = trunc i32 123 to i1 <i>; yields i1:true</i>
				3427	%Y = trunc i32 122 to i1 <i>; yields i1:false</i>
				3428	</pre>
				3429	</div>
				3430
				3431	<!-- _______________________________________________________________________ -->
				3432	<div class="doc_subsubsection">
				3433	<a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
				3434	</div>
				3435	<div class="doc_text">
				3436
				3437	<h5>Syntax:</h5>
				3438	<pre>
				3439	<result> = zext <ty> <value> to <ty2> <i>; yields ty2</i>
				3440	</pre>
				3441
				3442	<h5>Overview:</h5>
				3443	<p>The '<tt>zext</tt>' instruction zero extends its operand to type
				3444	<tt>ty2</tt>.</p>
				3445
				3446
				3447	<h5>Arguments:</h5>
				3448	<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
				3449	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3450	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3451	<tt>value</tt> must be smaller than the bit size of the destination type,
				3452	<tt>ty2</tt>.</p>
				3453
				3454	<h5>Semantics:</h5>
				3455	<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
				3456	bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
				3457
				3458	<p>When zero extending from i1, the result will always be either 0 or 1.</p>
				3459
				3460	<h5>Example:</h5>
				3461	<pre>
				3462	%X = zext i32 257 to i64 <i>; yields i64:257</i>
				3463	%Y = zext i1 true to i32 <i>; yields i32:1</i>
				3464	</pre>
				3465	</div>
				3466
				3467	<!-- _______________________________________________________________________ -->
				3468	<div class="doc_subsubsection">
				3469	<a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
				3470	</div>
				3471	<div class="doc_text">
				3472
				3473	<h5>Syntax:</h5>
				3474	<pre>
				3475	<result> = sext <ty> <value> to <ty2> <i>; yields ty2</i>
				3476	</pre>
				3477
				3478	<h5>Overview:</h5>
				3479	<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
				3480
				3481	<h5>Arguments:</h5>
				3482	<p>
				3483	The '<tt>sext</tt>' instruction takes a value to cast, which must be of
				3484	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3485	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3486	<tt>value</tt> must be smaller than the bit size of the destination type,
				3487	<tt>ty2</tt>.</p>
				3488
				3489	<h5>Semantics:</h5>
				3490	<p>
				3491	The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
				3492	bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
				3493	the type <tt>ty2</tt>.</p>
				3494
				3495	<p>When sign extending from i1, the extension always results in -1 or 0.</p>
				3496
				3497	<h5>Example:</h5>
				3498	<pre>
				3499	%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
				3500	%Y = sext i1 true to i32 <i>; yields i32:-1</i>
				3501	</pre>
				3502	</div>
				3503
				3504	<!-- _______________________________________________________________________ -->
				3505	<div class="doc_subsubsection">
				3506	<a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
				3507	</div>
				3508
				3509	<div class="doc_text">
				3510
				3511	<h5>Syntax:</h5>
				3512
				3513	<pre>
				3514	<result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3515	</pre>
				3516
				3517	<h5>Overview:</h5>
				3518	<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
				3519	<tt>ty2</tt>.</p>
				3520
				3521
				3522	<h5>Arguments:</h5>
				3523	<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
				3524	point</a> value to cast and a <a href="#t_floating">floating point</a> type to
				3525	cast it to. The size of <tt>value</tt> must be larger than the size of
				3526	<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
				3527	<i>no-op cast</i>.</p>
				3528
				3529	<h5>Semantics:</h5>
				3530	<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
				3531	<a href="#t_floating">floating point</a> type to a smaller
				3532	<a href="#t_floating">floating point</a> type. If the value cannot fit within
				3533	the destination type, <tt>ty2</tt>, then the results are undefined.</p>
				3534
				3535	<h5>Example:</h5>
				3536	<pre>
				3537	%X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
				3538	%Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
				3539	</pre>
				3540	</div>
				3541
				3542	<!-- _______________________________________________________________________ -->
				3543	<div class="doc_subsubsection">
				3544	<a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
				3545	</div>
				3546	<div class="doc_text">
				3547
				3548	<h5>Syntax:</h5>
				3549	<pre>
				3550	<result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i>
				3551	</pre>
				3552
				3553	<h5>Overview:</h5>
				3554	<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
				3555	floating point value.</p>
				3556
				3557	<h5>Arguments:</h5>
				3558	<p>The '<tt>fpext</tt>' instruction takes a
				3559	<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
				3560	and a <a href="#t_floating">floating point</a> type to cast it to. The source
				3561	type must be smaller than the destination type.</p>
				3562
				3563	<h5>Semantics:</h5>
				3564	<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
				3565	<a href="#t_floating">floating point</a> type to a larger
				3566	<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
				3567	used to make a <i>no-op cast</i> because it always changes bits. Use
				3568	<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
				3569
				3570	<h5>Example:</h5>
				3571	<pre>
				3572	%X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
				3573	%Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
				3574	</pre>
				3575	</div>
				3576
				3577	<!-- _______________________________________________________________________ -->
				3578	<div class="doc_subsubsection">
				3579	<a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
				3580	</div>
				3581	<div class="doc_text">
				3582
				3583	<h5>Syntax:</h5>
				3584	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3585	<result> = fptoui <ty> <value> to <ty2> <i>; yields ty2</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3586	</pre>
				3587
				3588	<h5>Overview:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3589	<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]	3590	unsigned integer equivalent of type <tt>ty2</tt>.
				3591	</p>
				3592
				3593	<h5>Arguments:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3594	<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]	3595	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3596	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3597	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3598	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]	3599
				3600	<h5>Semantics:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3601	<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3602	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3603	towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
				3604	the results are undefined.</p>
				3605
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3606	<h5>Example:</h5>
				3607	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3608	%X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3609	%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]	3610	%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]	3611	</pre>
				3612	</div>
				3613
				3614	<!-- _______________________________________________________________________ -->
				3615	<div class="doc_subsubsection">
				3616	<a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
				3617	</div>
				3618	<div class="doc_text">
				3619
				3620	<h5>Syntax:</h5>
				3621	<pre>
				3622	<result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i>
				3623	</pre>
				3624
				3625	<h5>Overview:</h5>
				3626	<p>The '<tt>fptosi</tt>' instruction converts
				3627	<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
				3628	</p>
				3629
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3630	<h5>Arguments:</h5>
				3631	<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]	3632	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3633	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3634	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3635	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]	3636
				3637	<h5>Semantics:</h5>
				3638	<p>The '<tt>fptosi</tt>' instruction converts its
				3639	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3640	towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
				3641	the results are undefined.</p>
				3642
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3643	<h5>Example:</h5>
				3644	<pre>
				3645	%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3646	%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]	3647	%X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
				3648	</pre>
				3649	</div>
				3650
				3651	<!-- _______________________________________________________________________ -->
				3652	<div class="doc_subsubsection">
				3653	<a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
				3654	</div>
				3655	<div class="doc_text">
				3656
				3657	<h5>Syntax:</h5>
				3658	<pre>
				3659	<result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3660	</pre>
				3661
				3662	<h5>Overview:</h5>
				3663	<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
				3664	integer and converts that value to the <tt>ty2</tt> type.</p>
				3665
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3666	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3667	<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
				3668	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3669	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3670	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3671	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]	3672
				3673	<h5>Semantics:</h5>
				3674	<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
				3675	integer quantity and converts it to the corresponding floating point value. If
				3676	the value cannot fit in the floating point value, the results are undefined.</p>
				3677
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3678	<h5>Example:</h5>
				3679	<pre>
				3680	%X = uitofp i32 257 to float <i>; yields float:257.0</i>
				3681	%Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
				3682	</pre>
				3683	</div>
				3684
				3685	<!-- _______________________________________________________________________ -->
				3686	<div class="doc_subsubsection">
				3687	<a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
				3688	</div>
				3689	<div class="doc_text">
				3690
				3691	<h5>Syntax:</h5>
				3692	<pre>
				3693	<result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3694	</pre>
				3695
				3696	<h5>Overview:</h5>
				3697	<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
				3698	integer and converts that value to the <tt>ty2</tt> type.</p>
				3699
				3700	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3701	<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
				3702	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3703	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3704	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3705	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]	3706
				3707	<h5>Semantics:</h5>
				3708	<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
				3709	integer quantity and converts it to the corresponding floating point value. If
				3710	the value cannot fit in the floating point value, the results are undefined.</p>
				3711
				3712	<h5>Example:</h5>
				3713	<pre>
				3714	%X = sitofp i32 257 to float <i>; yields float:257.0</i>
				3715	%Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
				3716	</pre>
				3717	</div>
				3718
				3719	<!-- _______________________________________________________________________ -->
				3720	<div class="doc_subsubsection">
				3721	<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
				3722	</div>
				3723	<div class="doc_text">
				3724
				3725	<h5>Syntax:</h5>
				3726	<pre>
				3727	<result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i>
				3728	</pre>
				3729
				3730	<h5>Overview:</h5>
				3731	<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
				3732	the integer type <tt>ty2</tt>.</p>
				3733
				3734	<h5>Arguments:</h5>
				3735	<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
				3736	must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
				3737	<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
				3738
				3739	<h5>Semantics:</h5>
				3740	<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
				3741	<tt>ty2</tt> by interpreting the pointer value as an integer and either
				3742	truncating or zero extending that value to the size of the integer type. If
				3743	<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
				3744	<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
				3745	are the same size, then nothing is done (<i>no-op cast</i>) other than a type
				3746	change.</p>
				3747
				3748	<h5>Example:</h5>
				3749	<pre>
				3750	%X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
				3751	%Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
				3752	</pre>
				3753	</div>
				3754
				3755	<!-- _______________________________________________________________________ -->
				3756	<div class="doc_subsubsection">
				3757	<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
				3758	</div>
				3759	<div class="doc_text">
				3760
				3761	<h5>Syntax:</h5>
				3762	<pre>
				3763	<result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i>
				3764	</pre>
				3765
				3766	<h5>Overview:</h5>
				3767	<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
				3768	a pointer type, <tt>ty2</tt>.</p>
				3769
				3770	<h5>Arguments:</h5>
				3771	<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
				3772	value to cast, and a type to cast it to, which must be a
				3773	<a href="#t_pointer">pointer</a> type.
				3774
				3775	<h5>Semantics:</h5>
				3776	<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
				3777	<tt>ty2</tt> by applying either a zero extension or a truncation depending on
				3778	the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
				3779	size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
				3780	the size of a pointer then a zero extension is done. If they are the same size,
				3781	nothing is done (<i>no-op cast</i>).</p>
				3782
				3783	<h5>Example:</h5>
				3784	<pre>
				3785	%X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
				3786	%X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
				3787	%Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
				3788	</pre>
				3789	</div>
				3790
				3791	<!-- _______________________________________________________________________ -->
				3792	<div class="doc_subsubsection">
				3793	<a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
				3794	</div>
				3795	<div class="doc_text">
				3796
				3797	<h5>Syntax:</h5>
				3798	<pre>
				3799	<result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i>
				3800	</pre>
				3801
				3802	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3803
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3804	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3805	<tt>ty2</tt> without changing any bits.</p>
				3806
				3807	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3808
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3809	<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
				3810	a first class value, and a type to cast it to, which must also be a <a
				3811	href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
				3812	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]	3813	type is a pointer, the destination type must also be a pointer. This
				3814	instruction supports bitwise conversion of vectors to integers and to vectors
				3815	of other types (as long as they have the same size).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3816
				3817	<h5>Semantics:</h5>
				3818	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3819	<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
				3820	this conversion. The conversion is done as if the <tt>value</tt> had been
				3821	stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
				3822	converted to other pointer types with this instruction. To convert pointers to
				3823	other types, use the <a href="#i_inttoptr">inttoptr</a> or
				3824	<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
				3825
				3826	<h5>Example:</h5>
				3827	<pre>
				3828	%X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
				3829	%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
				3830	%Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
				3831	</pre>
				3832	</div>
				3833
				3834	<!-- ======================================================================= -->
				3835	<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
				3836	<div class="doc_text">
				3837	<p>The instructions in this category are the "miscellaneous"
				3838	instructions, which defy better classification.</p>
				3839	</div>
				3840
				3841	<!-- _______________________________________________________________________ -->
				3842	<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
				3843	</div>
				3844	<div class="doc_text">
				3845	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3846	<pre> <result> = icmp <cond> <ty> <op1>, <op2> <i>; yields {i1}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3847	</pre>
				3848	<h5>Overview:</h5>
				3849	<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3850	of its two integer or pointer operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3851	<h5>Arguments:</h5>
				3852	<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
				3853	the condition code indicating the kind of comparison to perform. It is not
				3854	a value, just a keyword. The possible condition code are:
				3855	<ol>
				3856	<li><tt>eq</tt>: equal</li>
				3857	<li><tt>ne</tt>: not equal </li>
				3858	<li><tt>ugt</tt>: unsigned greater than</li>
				3859	<li><tt>uge</tt>: unsigned greater or equal</li>
				3860	<li><tt>ult</tt>: unsigned less than</li>
				3861	<li><tt>ule</tt>: unsigned less or equal</li>
				3862	<li><tt>sgt</tt>: signed greater than</li>
				3863	<li><tt>sge</tt>: signed greater or equal</li>
				3864	<li><tt>slt</tt>: signed less than</li>
				3865	<li><tt>sle</tt>: signed less or equal</li>
				3866	</ol>
				3867	<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
				3868	<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
				3869	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3870	<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]	3871	the condition code given as <tt>cond</tt>. The comparison performed always
				3872	yields a <a href="#t_primitive">i1</a> result, as follows:
				3873	<ol>
				3874	<li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
				3875	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3876	</li>
				3877	<li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
				3878	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3879	<li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3880	<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]	3881	<li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3882	<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]	3883	<li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3884	<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]	3885	<li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3886	<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]	3887	<li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3888	<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]	3889	<li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3890	<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]	3891	<li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3892	<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]	3893	<li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3894	<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]	3895	</ol>
				3896	<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
				3897	values are compared as if they were integers.</p>
				3898
				3899	<h5>Example:</h5>
				3900	<pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
				3901	<result> = icmp ne float* %X, %X <i>; yields: result=false</i>
				3902	<result> = icmp ult i16 4, 5 <i>; yields: result=true</i>
				3903	<result> = icmp sgt i16 4, 5 <i>; yields: result=false</i>
				3904	<result> = icmp ule i16 -4, 5 <i>; yields: result=false</i>
				3905	<result> = icmp sge i16 4, 5 <i>; yields: result=false</i>
				3906	</pre>
				3907	</div>
				3908
				3909	<!-- _______________________________________________________________________ -->
				3910	<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
				3911	</div>
				3912	<div class="doc_text">
				3913	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3914	<pre> <result> = fcmp <cond> <ty> <op1>, <op2> <i>; yields {i1}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3915	</pre>
				3916	<h5>Overview:</h5>
				3917	<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
				3918	of its floating point operands.</p>
				3919	<h5>Arguments:</h5>
				3920	<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
				3921	the condition code indicating the kind of comparison to perform. It is not
				3922	a value, just a keyword. The possible condition code are:
				3923	<ol>
				3924	<li><tt>false</tt>: no comparison, always returns false</li>
				3925	<li><tt>oeq</tt>: ordered and equal</li>
				3926	<li><tt>ogt</tt>: ordered and greater than </li>
				3927	<li><tt>oge</tt>: ordered and greater than or equal</li>
				3928	<li><tt>olt</tt>: ordered and less than </li>
				3929	<li><tt>ole</tt>: ordered and less than or equal</li>
				3930	<li><tt>one</tt>: ordered and not equal</li>
				3931	<li><tt>ord</tt>: ordered (no nans)</li>
				3932	<li><tt>ueq</tt>: unordered or equal</li>
				3933	<li><tt>ugt</tt>: unordered or greater than </li>
				3934	<li><tt>uge</tt>: unordered or greater than or equal</li>
				3935	<li><tt>ult</tt>: unordered or less than </li>
				3936	<li><tt>ule</tt>: unordered or less than or equal</li>
				3937	<li><tt>une</tt>: unordered or not equal</li>
				3938	<li><tt>uno</tt>: unordered (either nans)</li>
				3939	<li><tt>true</tt>: no comparison, always returns true</li>
				3940	</ol>
				3941	<p><i>Ordered</i> means that neither operand is a QNAN while
				3942	<i>unordered</i> means that either operand may be a QNAN.</p>
				3943	<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
				3944	<a href="#t_floating">floating point</a> typed. They must have identical
				3945	types.</p>
				3946	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3947	<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	3948	according to the condition code given as <tt>cond</tt>. The comparison performed
				3949	always yields a <a href="#t_primitive">i1</a> result, as follows:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3950	<ol>
				3951	<li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
				3952	<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]	3953	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3954	<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]	3955	<tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3956	<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]	3957	<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]	3958	<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]	3959	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3960	<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]	3961	<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]	3962	<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]	3963	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3964	<li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
				3965	<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]	3966	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3967	<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]	3968	<tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3969	<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]	3970	<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]	3971	<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]	3972	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3973	<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]	3974	<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]	3975	<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]	3976	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3977	<li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
				3978	<li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
				3979	</ol>
				3980
				3981	<h5>Example:</h5>
				3982	<pre> <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
				3983	<result> = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
				3984	<result> = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
				3985	<result> = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
				3986	</pre>
				3987	</div>
				3988
				3989	<!-- _______________________________________________________________________ -->
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	3990	<div class="doc_subsubsection">
				3991	<a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
				3992	</div>
				3993	<div class="doc_text">
				3994	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3995	<pre> <result> = vicmp <cond> <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	3996	</pre>
				3997	<h5>Overview:</h5>
				3998	<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
				3999	element-wise comparison of its two integer vector operands.</p>
				4000	<h5>Arguments:</h5>
				4001	<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
				4002	the condition code indicating the kind of comparison to perform. It is not
				4003	a value, just a keyword. The possible condition code are:
				4004	<ol>
				4005	<li><tt>eq</tt>: equal</li>
				4006	<li><tt>ne</tt>: not equal </li>
				4007	<li><tt>ugt</tt>: unsigned greater than</li>
				4008	<li><tt>uge</tt>: unsigned greater or equal</li>
				4009	<li><tt>ult</tt>: unsigned less than</li>
				4010	<li><tt>ule</tt>: unsigned less or equal</li>
				4011	<li><tt>sgt</tt>: signed greater than</li>
				4012	<li><tt>sge</tt>: signed greater or equal</li>
				4013	<li><tt>slt</tt>: signed less than</li>
				4014	<li><tt>sle</tt>: signed less or equal</li>
				4015	</ol>
				4016	<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
				4017	<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
				4018	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4019	<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]	4020	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4021	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
				4022	identical type as the values being compared. The most significant bit in each
				4023	element is 1 if the element-wise comparison evaluates to true, and is 0
				4024	otherwise. All other bits of the result are undefined. The condition codes
				4025	are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
				4026	instruction</a>.
				4027
				4028	<h5>Example:</h5>
				4029	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4030	<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>
				4031	<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]	4032	</pre>
				4033	</div>
				4034
				4035	<!-- _______________________________________________________________________ -->
				4036	<div class="doc_subsubsection">
				4037	<a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
				4038	</div>
				4039	<div class="doc_text">
				4040	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4041	<pre> <result> = vfcmp <cond> <ty> <op1>, <op2></pre>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4042	<h5>Overview:</h5>
				4043	<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
				4044	element-wise comparison of its two floating point vector operands. The output
				4045	elements have the same width as the input elements.</p>
				4046	<h5>Arguments:</h5>
				4047	<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
				4048	the condition code indicating the kind of comparison to perform. It is not
				4049	a value, just a keyword. The possible condition code are:
				4050	<ol>
				4051	<li><tt>false</tt>: no comparison, always returns false</li>
				4052	<li><tt>oeq</tt>: ordered and equal</li>
				4053	<li><tt>ogt</tt>: ordered and greater than </li>
				4054	<li><tt>oge</tt>: ordered and greater than or equal</li>
				4055	<li><tt>olt</tt>: ordered and less than </li>
				4056	<li><tt>ole</tt>: ordered and less than or equal</li>
				4057	<li><tt>one</tt>: ordered and not equal</li>
				4058	<li><tt>ord</tt>: ordered (no nans)</li>
				4059	<li><tt>ueq</tt>: unordered or equal</li>
				4060	<li><tt>ugt</tt>: unordered or greater than </li>
				4061	<li><tt>uge</tt>: unordered or greater than or equal</li>
				4062	<li><tt>ult</tt>: unordered or less than </li>
				4063	<li><tt>ule</tt>: unordered or less than or equal</li>
				4064	<li><tt>une</tt>: unordered or not equal</li>
				4065	<li><tt>uno</tt>: unordered (either nans)</li>
				4066	<li><tt>true</tt>: no comparison, always returns true</li>
				4067	</ol>
				4068	<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
				4069	<a href="#t_floating">floating point</a> typed. They must also be identical
				4070	types.</p>
				4071	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4072	<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]	4073	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4074	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
				4075	an identical number of elements as the values being compared, and each element
				4076	having identical with to the width of the floating point elements. The most
				4077	significant bit in each element is 1 if the element-wise comparison evaluates to
				4078	true, and is 0 otherwise. All other bits of the result are undefined. The
				4079	condition codes are evaluated identically to the
				4080	<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
				4081
				4082	<h5>Example:</h5>
				4083	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4084	<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>
				4085	<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]	4086	</pre>
				4087	</div>
				4088
				4089	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4090	<div class="doc_subsubsection">
				4091	<a name="i_phi">'<tt>phi</tt>' Instruction</a>
				4092	</div>
				4093
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4094	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4095
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4096	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4097
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4098	<pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre>
				4099	<h5>Overview:</h5>
				4100	<p>The '<tt>phi</tt>' instruction is used to implement the φ node in
				4101	the SSA graph representing the function.</p>
				4102	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4103
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4104	<p>The type of the incoming values is specified with the first type
				4105	field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
				4106	as arguments, with one pair for each predecessor basic block of the
				4107	current block. Only values of <a href="#t_firstclass">first class</a>
				4108	type may be used as the value arguments to the PHI node. Only labels
				4109	may be used as the label arguments.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4110
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4111	<p>There must be no non-phi instructions between the start of a basic
				4112	block and the PHI instructions: i.e. PHI instructions must be first in
				4113	a basic block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4114
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4115	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4116
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4117	<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
				4118	specified by the pair corresponding to the predecessor basic block that executed
				4119	just prior to the current block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4120
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4121	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4122	<pre>
				4123	Loop: ; Infinite loop that counts from 0 on up...
				4124	%indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
				4125	%nextindvar = add i32 %indvar, 1
				4126	br label %Loop
				4127	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4128	</div>
				4129
				4130	<!-- _______________________________________________________________________ -->
				4131	<div class="doc_subsubsection">
				4132	<a name="i_select">'<tt>select</tt>' Instruction</a>
				4133	</div>
				4134
				4135	<div class="doc_text">
				4136
				4137	<h5>Syntax:</h5>
				4138
				4139	<pre>
				4140	<result> = select i1 <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
				4141	</pre>
				4142
				4143	<h5>Overview:</h5>
				4144
				4145	<p>
				4146	The '<tt>select</tt>' instruction is used to choose one value based on a
				4147	condition, without branching.
				4148	</p>
				4149
				4150
				4151	<h5>Arguments:</h5>
				4152
				4153	<p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4154	The '<tt>select</tt>' instruction requires an 'i1' value indicating the
				4155	condition, and two values of the same <a href="#t_firstclass">first class</a>
				4156	type. If the val1/val2 are vectors, the entire vectors are selected, not
				4157	individual elements.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4158	</p>
				4159
				4160	<h5>Semantics:</h5>
				4161
				4162	<p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4163	If the i1 condition evaluates is 1, the instruction returns the first
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4164	value argument; otherwise, it returns the second value argument.
				4165	</p>
				4166
				4167	<h5>Example:</h5>
				4168
				4169	<pre>
				4170	%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
				4171	</pre>
				4172	</div>
				4173
				4174
				4175	<!-- _______________________________________________________________________ -->
				4176	<div class="doc_subsubsection">
				4177	<a name="i_call">'<tt>call</tt>' Instruction</a>
				4178	</div>
				4179
				4180	<div class="doc_text">
				4181
				4182	<h5>Syntax:</h5>
				4183	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4184	<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]	4185	</pre>
				4186
				4187	<h5>Overview:</h5>
				4188
				4189	<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
				4190
				4191	<h5>Arguments:</h5>
				4192
				4193	<p>This instruction requires several arguments:</p>
				4194
				4195	<ol>
				4196	<li>
				4197	<p>The optional "tail" marker indicates whether the callee function accesses
				4198	any allocas or varargs in the caller. If the "tail" marker is present, the
				4199	function call is eligible for tail call optimization. Note that calls may
				4200	be marked "tail" even if they do not occur before a <a
				4201	href="#i_ret"><tt>ret</tt></a> instruction.
				4202	</li>
				4203	<li>
				4204	<p>The optional "cconv" marker indicates which <a href="#callingconv">calling
				4205	convention</a> the call should use. If none is specified, the call defaults
				4206	to using C calling conventions.
				4207	</li>
				4208	<li>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4209	<p>'<tt>ty</tt>': the type of the call instruction itself which is also
				4210	the type of the return value. Functions that return no value are marked
				4211	<tt><a href="#t_void">void</a></tt>.</p>
				4212	</li>
				4213	<li>
				4214	<p>'<tt>fnty</tt>': shall be the signature of the pointer to function
				4215	value being invoked. The argument types must match the types implied by
				4216	this signature. This type can be omitted if the function is not varargs
				4217	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]	4218	</li>
				4219	<li>
				4220	<p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
				4221	be invoked. In most cases, this is a direct function invocation, but
				4222	indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
				4223	to function value.</p>
				4224	</li>
				4225	<li>
				4226	<p>'<tt>function args</tt>': argument list whose types match the
				4227	function signature argument types. All arguments must be of
				4228	<a href="#t_firstclass">first class</a> type. If the function signature
				4229	indicates the function accepts a variable number of arguments, the extra
				4230	arguments can be specified.</p>
				4231	</li>
				4232	</ol>
				4233
				4234	<h5>Semantics:</h5>
				4235
				4236	<p>The '<tt>call</tt>' instruction is used to cause control flow to
				4237	transfer to a specified function, with its incoming arguments bound to
				4238	the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
				4239	instruction in the called function, control flow continues with the
				4240	instruction after the function call, and the return value of the
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4241	function is bound to the result argument. If the callee returns multiple
				4242	values then the return values of the function are only accessible through
				4243	the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4244
				4245	<h5>Example:</h5>
				4246
				4247	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4248	%retval = call i32 @test(i32 %argc)
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4249	call i32 (i8 , ...) @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
				4250	%X = tail call i32 @foo() <i>; yields i32</i>
				4251	%Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
				4252	call void %foo(i8 97 signext)
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4253
				4254	%struct.A = type { i32, i8 }
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4255	%r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
				4256	%gr = getresult %struct.A %r, 0 <i>; yields i32</i>
				4257	%gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4258	</pre>
				4259
				4260	</div>
				4261
				4262	<!-- _______________________________________________________________________ -->
				4263	<div class="doc_subsubsection">
				4264	<a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
				4265	</div>
				4266
				4267	<div class="doc_text">
				4268
				4269	<h5>Syntax:</h5>
				4270
				4271	<pre>
				4272	<resultval> = va_arg <va_list*> <arglist>, <argty>
				4273	</pre>
				4274
				4275	<h5>Overview:</h5>
				4276
				4277	<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
				4278	the "variable argument" area of a function call. It is used to implement the
				4279	<tt>va_arg</tt> macro in C.</p>
				4280
				4281	<h5>Arguments:</h5>
				4282
				4283	<p>This instruction takes a <tt>va_list*</tt> value and the type of
				4284	the argument. It returns a value of the specified argument type and
				4285	increments the <tt>va_list</tt> to point to the next argument. The
				4286	actual type of <tt>va_list</tt> is target specific.</p>
				4287
				4288	<h5>Semantics:</h5>
				4289
				4290	<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
				4291	type from the specified <tt>va_list</tt> and causes the
				4292	<tt>va_list</tt> to point to the next argument. For more information,
				4293	see the variable argument handling <a href="#int_varargs">Intrinsic
				4294	Functions</a>.</p>
				4295
				4296	<p>It is legal for this instruction to be called in a function which does not
				4297	take a variable number of arguments, for example, the <tt>vfprintf</tt>
				4298	function.</p>
				4299
				4300	<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
				4301	href="#intrinsics">intrinsic function</a> because it takes a type as an
				4302	argument.</p>
				4303
				4304	<h5>Example:</h5>
				4305
				4306	<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
				4307
				4308	</div>
				4309
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4310	<!-- _______________________________________________________________________ -->
				4311	<div class="doc_subsubsection">
				4312	<a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
				4313	</div>
				4314
				4315	<div class="doc_text">
				4316
				4317	<h5>Syntax:</h5>
				4318	<pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4319	<resultval> = getresult <type> <retval>, <index>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4320	</pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4321
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4322	<h5>Overview:</h5>
				4323
				4324	<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4325	from a '<tt><a href="#i_call">call</a></tt>'
				4326	or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
				4327	results.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4328
				4329	<h5>Arguments:</h5>
				4330
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4331	<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]	4332	first argument, or an undef value. The value must have <a
				4333	href="#t_struct">structure type</a>. The second argument is a constant
				4334	unsigned index value which must be in range for the number of values returned
				4335	by the call.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4336
				4337	<h5>Semantics:</h5>
				4338
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4339	<p>The '<tt>getresult</tt>' instruction extracts the element identified by
				4340	'<tt>index</tt>' from the aggregate value.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4341
				4342	<h5>Example:</h5>
				4343
				4344	<pre>
				4345	%struct.A = type { i32, i8 }
				4346
				4347	%r = call %struct.A @foo()
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4348	%gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
				4349	%gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4350	add i32 %gr, 42
				4351	add i8 %gr1, 41
				4352	</pre>
				4353
				4354	</div>
				4355
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4356	<!-- *********************************************************************** -->
				4357	<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
				4358	<!-- *********************************************************************** -->
				4359
				4360	<div class="doc_text">
				4361
				4362	<p>LLVM supports the notion of an "intrinsic function". These functions have
				4363	well known names and semantics and are required to follow certain restrictions.
				4364	Overall, these intrinsics represent an extension mechanism for the LLVM
				4365	language that does not require changing all of the transformations in LLVM when
				4366	adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
				4367
				4368	<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
				4369	prefix is reserved in LLVM for intrinsic names; thus, function names may not
				4370	begin with this prefix. Intrinsic functions must always be external functions:
				4371	you cannot define the body of intrinsic functions. Intrinsic functions may
				4372	only be used in call or invoke instructions: it is illegal to take the address
				4373	of an intrinsic function. Additionally, because intrinsic functions are part
				4374	of the LLVM language, it is required if any are added that they be documented
				4375	here.</p>
				4376
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4377	<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
				4378	a family of functions that perform the same operation but on different data
				4379	types. Because LLVM can represent over 8 million different integer types,
				4380	overloading is used commonly to allow an intrinsic function to operate on any
				4381	integer type. One or more of the argument types or the result type can be
				4382	overloaded to accept any integer type. Argument types may also be defined as
				4383	exactly matching a previous argument's type or the result type. This allows an
				4384	intrinsic function which accepts multiple arguments, but needs all of them to
				4385	be of the same type, to only be overloaded with respect to a single argument or
				4386	the result.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4387
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4388	<p>Overloaded intrinsics will have the names of its overloaded argument types
				4389	encoded into its function name, each preceded by a period. Only those types
				4390	which are overloaded result in a name suffix. Arguments whose type is matched
				4391	against another type do not. For example, the <tt>llvm.ctpop</tt> function can
				4392	take an integer of any width and returns an integer of exactly the same integer
				4393	width. This leads to a family of functions such as
				4394	<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
				4395	Only one type, the return type, is overloaded, and only one type suffix is
				4396	required. Because the argument's type is matched against the return type, it
				4397	does not require its own name suffix.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4398
				4399	<p>To learn how to add an intrinsic function, please see the
				4400	<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
				4401	</p>
				4402
				4403	</div>
				4404
				4405	<!-- ======================================================================= -->
				4406	<div class="doc_subsection">
				4407	<a name="int_varargs">Variable Argument Handling Intrinsics</a>
				4408	</div>
				4409
				4410	<div class="doc_text">
				4411
				4412	<p>Variable argument support is defined in LLVM with the <a
				4413	href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
				4414	intrinsic functions. These functions are related to the similarly
				4415	named macros defined in the <tt><stdarg.h></tt> header file.</p>
				4416
				4417	<p>All of these functions operate on arguments that use a
				4418	target-specific value type "<tt>va_list</tt>". The LLVM assembly
				4419	language reference manual does not define what this type is, so all
				4420	transformations should be prepared to handle these functions regardless of
				4421	the type used.</p>
				4422
				4423	<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
				4424	instruction and the variable argument handling intrinsic functions are
				4425	used.</p>
				4426
				4427	<div class="doc_code">
				4428	<pre>
				4429	define i32 @test(i32 %X, ...) {
				4430	; Initialize variable argument processing
				4431	%ap = alloca i8*
				4432	%ap2 = bitcast i8** %ap to i8*
				4433	call void @llvm.va_start(i8* %ap2)
				4434
				4435	; Read a single integer argument
				4436	%tmp = va_arg i8** %ap, i32
				4437
				4438	; Demonstrate usage of llvm.va_copy and llvm.va_end
				4439	%aq = alloca i8*
				4440	%aq2 = bitcast i8** %aq to i8*
				4441	call void @llvm.va_copy(i8* %aq2, i8* %ap2)
				4442	call void @llvm.va_end(i8* %aq2)
				4443
				4444	; Stop processing of arguments.
				4445	call void @llvm.va_end(i8* %ap2)
				4446	ret i32 %tmp
				4447	}
				4448
				4449	declare void @llvm.va_start(i8*)
				4450	declare void @llvm.va_copy(i8, i8)
				4451	declare void @llvm.va_end(i8*)
				4452	</pre>
				4453	</div>
				4454
				4455	</div>
				4456
				4457	<!-- _______________________________________________________________________ -->
				4458	<div class="doc_subsubsection">
				4459	<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
				4460	</div>
				4461
				4462
				4463	<div class="doc_text">
				4464	<h5>Syntax:</h5>
				4465	<pre> declare void %llvm.va_start(i8* <arglist>)<br></pre>
				4466	<h5>Overview:</h5>
				4467	<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
				4468	<tt>*<arglist></tt> for subsequent use by <tt><a
				4469	href="#i_va_arg">va_arg</a></tt>.</p>
				4470
				4471	<h5>Arguments:</h5>
				4472
				4473	<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
				4474
				4475	<h5>Semantics:</h5>
				4476
				4477	<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
				4478	macro available in C. In a target-dependent way, it initializes the
				4479	<tt>va_list</tt> element to which the argument points, so that the next call to
				4480	<tt>va_arg</tt> will produce the first variable argument passed to the function.
				4481	Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
				4482	last argument of the function as the compiler can figure that out.</p>
				4483
				4484	</div>
				4485
				4486	<!-- _______________________________________________________________________ -->
				4487	<div class="doc_subsubsection">
				4488	<a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
				4489	</div>
				4490
				4491	<div class="doc_text">
				4492	<h5>Syntax:</h5>
				4493	<pre> declare void @llvm.va_end(i8* <arglist>)<br></pre>
				4494	<h5>Overview:</h5>
				4495
				4496	<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
				4497	which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
				4498	or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
				4499
				4500	<h5>Arguments:</h5>
				4501
				4502	<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
				4503
				4504	<h5>Semantics:</h5>
				4505
				4506	<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
				4507	macro available in C. In a target-dependent way, it destroys the
				4508	<tt>va_list</tt> element to which the argument points. Calls to <a
				4509	href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
				4510	<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
				4511	<tt>llvm.va_end</tt>.</p>
				4512
				4513	</div>
				4514
				4515	<!-- _______________________________________________________________________ -->
				4516	<div class="doc_subsubsection">
				4517	<a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
				4518	</div>
				4519
				4520	<div class="doc_text">
				4521
				4522	<h5>Syntax:</h5>
				4523
				4524	<pre>
				4525	declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)
				4526	</pre>
				4527
				4528	<h5>Overview:</h5>
				4529
				4530	<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
				4531	from the source argument list to the destination argument list.</p>
				4532
				4533	<h5>Arguments:</h5>
				4534
				4535	<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
				4536	The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
				4537
				4538
				4539	<h5>Semantics:</h5>
				4540
				4541	<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
				4542	macro available in C. In a target-dependent way, it copies the source
				4543	<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
				4544	intrinsic is necessary because the <tt><a href="#int_va_start">
				4545	llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
				4546	example, memory allocation.</p>
				4547
				4548	</div>
				4549
				4550	<!-- ======================================================================= -->
				4551	<div class="doc_subsection">
				4552	<a name="int_gc">Accurate Garbage Collection Intrinsics</a>
				4553	</div>
				4554
				4555	<div class="doc_text">
				4556
				4557	<p>
				4558	LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	4559	Collection</a> (GC) requires the implementation and generation of these
				4560	intrinsics.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4561	These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
				4562	stack</a>, as well as garbage collector implementations that require <a
				4563	href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
				4564	Front-ends for type-safe garbage collected languages should generate these
				4565	intrinsics to make use of the LLVM garbage collectors. For more details, see <a
				4566	href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
				4567	</p>
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	4568
				4569	<p>The garbage collection intrinsics only operate on objects in the generic
				4570	address space (address space zero).</p>
				4571
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4572	</div>
				4573
				4574	<!-- _______________________________________________________________________ -->
				4575	<div class="doc_subsubsection">
				4576	<a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
				4577	</div>
				4578
				4579	<div class="doc_text">
				4580
				4581	<h5>Syntax:</h5>
				4582
				4583	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4584	declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4585	</pre>
				4586
				4587	<h5>Overview:</h5>
				4588
				4589	<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
				4590	the code generator, and allows some metadata to be associated with it.</p>
				4591
				4592	<h5>Arguments:</h5>
				4593
				4594	<p>The first argument specifies the address of a stack object that contains the
				4595	root pointer. The second pointer (which must be either a constant or a global
				4596	value address) contains the meta-data to be associated with the root.</p>
				4597
				4598	<h5>Semantics:</h5>
				4599
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	4600	<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]	4601	location. At compile-time, the code generator generates information to allow
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4602	the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
				4603	intrinsic may only be used in a function which <a href="#gc">specifies a GC
				4604	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4605
				4606	</div>
				4607
				4608
				4609	<!-- _______________________________________________________________________ -->
				4610	<div class="doc_subsubsection">
				4611	<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
				4612	</div>
				4613
				4614	<div class="doc_text">
				4615
				4616	<h5>Syntax:</h5>
				4617
				4618	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4619	declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4620	</pre>
				4621
				4622	<h5>Overview:</h5>
				4623
				4624	<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
				4625	locations, allowing garbage collector implementations that require read
				4626	barriers.</p>
				4627
				4628	<h5>Arguments:</h5>
				4629
				4630	<p>The second argument is the address to read from, which should be an address
				4631	allocated from the garbage collector. The first object is a pointer to the
				4632	start of the referenced object, if needed by the language runtime (otherwise
				4633	null).</p>
				4634
				4635	<h5>Semantics:</h5>
				4636
				4637	<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
				4638	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4639	garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
				4640	may only be used in a function which <a href="#gc">specifies a GC
				4641	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4642
				4643	</div>
				4644
				4645
				4646	<!-- _______________________________________________________________________ -->
				4647	<div class="doc_subsubsection">
				4648	<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
				4649	</div>
				4650
				4651	<div class="doc_text">
				4652
				4653	<h5>Syntax:</h5>
				4654
				4655	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4656	declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4657	</pre>
				4658
				4659	<h5>Overview:</h5>
				4660
				4661	<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
				4662	locations, allowing garbage collector implementations that require write
				4663	barriers (such as generational or reference counting collectors).</p>
				4664
				4665	<h5>Arguments:</h5>
				4666
				4667	<p>The first argument is the reference to store, the second is the start of the
				4668	object to store it to, and the third is the address of the field of Obj to
				4669	store to. If the runtime does not require a pointer to the object, Obj may be
				4670	null.</p>
				4671
				4672	<h5>Semantics:</h5>
				4673
				4674	<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
				4675	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4676	garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
				4677	may only be used in a function which <a href="#gc">specifies a GC
				4678	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4679
				4680	</div>
				4681
				4682
				4683
				4684	<!-- ======================================================================= -->
				4685	<div class="doc_subsection">
				4686	<a name="int_codegen">Code Generator Intrinsics</a>
				4687	</div>
				4688
				4689	<div class="doc_text">
				4690	<p>
				4691	These intrinsics are provided by LLVM to expose special features that may only
				4692	be implemented with code generator support.
				4693	</p>
				4694
				4695	</div>
				4696
				4697	<!-- _______________________________________________________________________ -->
				4698	<div class="doc_subsubsection">
				4699	<a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
				4700	</div>
				4701
				4702	<div class="doc_text">
				4703
				4704	<h5>Syntax:</h5>
				4705	<pre>
				4706	declare i8 *@llvm.returnaddress(i32 <level>)
				4707	</pre>
				4708
				4709	<h5>Overview:</h5>
				4710
				4711	<p>
				4712	The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
				4713	target-specific value indicating the return address of the current function
				4714	or one of its callers.
				4715	</p>
				4716
				4717	<h5>Arguments:</h5>
				4718
				4719	<p>
				4720	The argument to this intrinsic indicates which function to return the address
				4721	for. Zero indicates the calling function, one indicates its caller, etc. The
				4722	argument is <b>required</b> to be a constant integer value.
				4723	</p>
				4724
				4725	<h5>Semantics:</h5>
				4726
				4727	<p>
				4728	The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
				4729	the return address of the specified call frame, or zero if it cannot be
				4730	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4731	for arguments other than zero, so it should only be used for debugging purposes.
				4732	</p>
				4733
				4734	<p>
				4735	Note that calling this intrinsic does not prevent function inlining or other
				4736	aggressive transformations, so the value returned may not be that of the obvious
				4737	source-language caller.
				4738	</p>
				4739	</div>
				4740
				4741
				4742	<!-- _______________________________________________________________________ -->
				4743	<div class="doc_subsubsection">
				4744	<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
				4745	</div>
				4746
				4747	<div class="doc_text">
				4748
				4749	<h5>Syntax:</h5>
				4750	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4751	declare i8 *@llvm.frameaddress(i32 <level>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4752	</pre>
				4753
				4754	<h5>Overview:</h5>
				4755
				4756	<p>
				4757	The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
				4758	target-specific frame pointer value for the specified stack frame.
				4759	</p>
				4760
				4761	<h5>Arguments:</h5>
				4762
				4763	<p>
				4764	The argument to this intrinsic indicates which function to return the frame
				4765	pointer for. Zero indicates the calling function, one indicates its caller,
				4766	etc. The argument is <b>required</b> to be a constant integer value.
				4767	</p>
				4768
				4769	<h5>Semantics:</h5>
				4770
				4771	<p>
				4772	The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
				4773	the frame address of the specified call frame, or zero if it cannot be
				4774	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4775	for arguments other than zero, so it should only be used for debugging purposes.
				4776	</p>
				4777
				4778	<p>
				4779	Note that calling this intrinsic does not prevent function inlining or other
				4780	aggressive transformations, so the value returned may not be that of the obvious
				4781	source-language caller.
				4782	</p>
				4783	</div>
				4784
				4785	<!-- _______________________________________________________________________ -->
				4786	<div class="doc_subsubsection">
				4787	<a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
				4788	</div>
				4789
				4790	<div class="doc_text">
				4791
				4792	<h5>Syntax:</h5>
				4793	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4794	declare i8 *@llvm.stacksave()
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4795	</pre>
				4796
				4797	<h5>Overview:</h5>
				4798
				4799	<p>
				4800	The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
				4801	the function stack, for use with <a href="#int_stackrestore">
				4802	<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
				4803	features like scoped automatic variable sized arrays in C99.
				4804	</p>
				4805
				4806	<h5>Semantics:</h5>
				4807
				4808	<p>
				4809	This intrinsic returns a opaque pointer value that can be passed to <a
				4810	href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
				4811	<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
				4812	<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
				4813	state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
				4814	practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
				4815	that were allocated after the <tt>llvm.stacksave</tt> was executed.
				4816	</p>
				4817
				4818	</div>
				4819
				4820	<!-- _______________________________________________________________________ -->
				4821	<div class="doc_subsubsection">
				4822	<a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
				4823	</div>
				4824
				4825	<div class="doc_text">
				4826
				4827	<h5>Syntax:</h5>
				4828	<pre>
				4829	declare void @llvm.stackrestore(i8 * %ptr)
				4830	</pre>
				4831
				4832	<h5>Overview:</h5>
				4833
				4834	<p>
				4835	The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
				4836	the function stack to the state it was in when the corresponding <a
				4837	href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
				4838	useful for implementing language features like scoped automatic variable sized
				4839	arrays in C99.
				4840	</p>
				4841
				4842	<h5>Semantics:</h5>
				4843
				4844	<p>
				4845	See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
				4846	</p>
				4847
				4848	</div>
				4849
				4850
				4851	<!-- _______________________________________________________________________ -->
				4852	<div class="doc_subsubsection">
				4853	<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
				4854	</div>
				4855
				4856	<div class="doc_text">
				4857
				4858	<h5>Syntax:</h5>
				4859	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4860	declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4861	</pre>
				4862
				4863	<h5>Overview:</h5>
				4864
				4865
				4866	<p>
				4867	The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
				4868	a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
				4869	no
				4870	effect on the behavior of the program but can change its performance
				4871	characteristics.
				4872	</p>
				4873
				4874	<h5>Arguments:</h5>
				4875
				4876	<p>
				4877	<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
				4878	determining if the fetch should be for a read (0) or write (1), and
				4879	<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
				4880	locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
				4881	<tt>locality</tt> arguments must be constant integers.
				4882	</p>
				4883
				4884	<h5>Semantics:</h5>
				4885
				4886	<p>
				4887	This intrinsic does not modify the behavior of the program. In particular,
				4888	prefetches cannot trap and do not produce a value. On targets that support this
				4889	intrinsic, the prefetch can provide hints to the processor cache for better
				4890	performance.
				4891	</p>
				4892
				4893	</div>
				4894
				4895	<!-- _______________________________________________________________________ -->
				4896	<div class="doc_subsubsection">
				4897	<a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
				4898	</div>
				4899
				4900	<div class="doc_text">
				4901
				4902	<h5>Syntax:</h5>
				4903	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4904	declare void @llvm.pcmarker(i32 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4905	</pre>
				4906
				4907	<h5>Overview:</h5>
				4908
				4909
				4910	<p>
				4911	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]	4912	(PC) in a region of
				4913	code to simulators and other tools. The method is target specific, but it is
				4914	expected that the marker will use exported symbols to transmit the PC of the
				4915	marker.
				4916	The marker makes no guarantees that it will remain with any specific instruction
				4917	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]	4918	optimizations. The intended use is to be inserted after optimizations to allow
				4919	correlations of simulation runs.
				4920	</p>
				4921
				4922	<h5>Arguments:</h5>
				4923
				4924	<p>
				4925	<tt>id</tt> is a numerical id identifying the marker.
				4926	</p>
				4927
				4928	<h5>Semantics:</h5>
				4929
				4930	<p>
				4931	This intrinsic does not modify the behavior of the program. Backends that do not
				4932	support this intrinisic may ignore it.
				4933	</p>
				4934
				4935	</div>
				4936
				4937	<!-- _______________________________________________________________________ -->
				4938	<div class="doc_subsubsection">
				4939	<a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
				4940	</div>
				4941
				4942	<div class="doc_text">
				4943
				4944	<h5>Syntax:</h5>
				4945	<pre>
				4946	declare i64 @llvm.readcyclecounter( )
				4947	</pre>
				4948
				4949	<h5>Overview:</h5>
				4950
				4951
				4952	<p>
				4953	The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
				4954	counter register (or similar low latency, high accuracy clocks) on those targets
				4955	that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
				4956	As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
				4957	should only be used for small timings.
				4958	</p>
				4959
				4960	<h5>Semantics:</h5>
				4961
				4962	<p>
				4963	When directly supported, reading the cycle counter should not modify any memory.
				4964	Implementations are allowed to either return a application specific value or a
				4965	system wide value. On backends without support, this is lowered to a constant 0.
				4966	</p>
				4967
				4968	</div>
				4969
				4970	<!-- ======================================================================= -->
				4971	<div class="doc_subsection">
				4972	<a name="int_libc">Standard C Library Intrinsics</a>
				4973	</div>
				4974
				4975	<div class="doc_text">
				4976	<p>
				4977	LLVM provides intrinsics for a few important standard C library functions.
				4978	These intrinsics allow source-language front-ends to pass information about the
				4979	alignment of the pointer arguments to the code generator, providing opportunity
				4980	for more efficient code generation.
				4981	</p>
				4982
				4983	</div>
				4984
				4985	<!-- _______________________________________________________________________ -->
				4986	<div class="doc_subsubsection">
				4987	<a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
				4988	</div>
				4989
				4990	<div class="doc_text">
				4991
				4992	<h5>Syntax:</h5>
				4993	<pre>
				4994	declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
				4995	i32 <len>, i32 <align>)
				4996	declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>,
				4997	i64 <len>, i32 <align>)
				4998	</pre>
				4999
				5000	<h5>Overview:</h5>
				5001
				5002	<p>
				5003	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5004	location to the destination location.
				5005	</p>
				5006
				5007	<p>
				5008	Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
				5009	intrinsics do not return a value, and takes an extra alignment argument.
				5010	</p>
				5011
				5012	<h5>Arguments:</h5>
				5013
				5014	<p>
				5015	The first argument is a pointer to the destination, the second is a pointer to
				5016	the source. The third argument is an integer argument
				5017	specifying the number of bytes to copy, and the fourth argument is the alignment
				5018	of the source and destination locations.
				5019	</p>
				5020
				5021	<p>
				5022	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5023	the caller guarantees that both the source and destination pointers are aligned
				5024	to that boundary.
				5025	</p>
				5026
				5027	<h5>Semantics:</h5>
				5028
				5029	<p>
				5030	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5031	location to the destination location, which are not allowed to overlap. It
				5032	copies "len" bytes of memory over. If the argument is known to be aligned to
				5033	some boundary, this can be specified as the fourth argument, otherwise it should
				5034	be set to 0 or 1.
				5035	</p>
				5036	</div>
				5037
				5038
				5039	<!-- _______________________________________________________________________ -->
				5040	<div class="doc_subsubsection">
				5041	<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
				5042	</div>
				5043
				5044	<div class="doc_text">
				5045
				5046	<h5>Syntax:</h5>
				5047	<pre>
				5048	declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
				5049	i32 <len>, i32 <align>)
				5050	declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>,
				5051	i64 <len>, i32 <align>)
				5052	</pre>
				5053
				5054	<h5>Overview:</h5>
				5055
				5056	<p>
				5057	The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
				5058	location to the destination location. It is similar to the
Chris Lattner	dba16ea	2008-01-06 19:51:52 +0000	[diff] [blame]	5059	'<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]	5060	</p>
				5061
				5062	<p>
				5063	Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
				5064	intrinsics do not return a value, and takes an extra alignment argument.
				5065	</p>
				5066
				5067	<h5>Arguments:</h5>
				5068
				5069	<p>
				5070	The first argument is a pointer to the destination, the second is a pointer to
				5071	the source. The third argument is an integer argument
				5072	specifying the number of bytes to copy, and the fourth argument is the alignment
				5073	of the source and destination locations.
				5074	</p>
				5075
				5076	<p>
				5077	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5078	the caller guarantees that the source and destination pointers are aligned to
				5079	that boundary.
				5080	</p>
				5081
				5082	<h5>Semantics:</h5>
				5083
				5084	<p>
				5085	The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
				5086	location to the destination location, which may overlap. It
				5087	copies "len" bytes of memory over. If the argument is known to be aligned to
				5088	some boundary, this can be specified as the fourth argument, otherwise it should
				5089	be set to 0 or 1.
				5090	</p>
				5091	</div>
				5092
				5093
				5094	<!-- _______________________________________________________________________ -->
				5095	<div class="doc_subsubsection">
				5096	<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
				5097	</div>
				5098
				5099	<div class="doc_text">
				5100
				5101	<h5>Syntax:</h5>
				5102	<pre>
				5103	declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
				5104	i32 <len>, i32 <align>)
				5105	declare void @llvm.memset.i64(i8 * <dest>, i8 <val>,
				5106	i64 <len>, i32 <align>)
				5107	</pre>
				5108
				5109	<h5>Overview:</h5>
				5110
				5111	<p>
				5112	The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
				5113	byte value.
				5114	</p>
				5115
				5116	<p>
				5117	Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
				5118	does not return a value, and takes an extra alignment argument.
				5119	</p>
				5120
				5121	<h5>Arguments:</h5>
				5122
				5123	<p>
				5124	The first argument is a pointer to the destination to fill, the second is the
				5125	byte value to fill it with, the third argument is an integer
				5126	argument specifying the number of bytes to fill, and the fourth argument is the
				5127	known alignment of destination location.
				5128	</p>
				5129
				5130	<p>
				5131	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5132	the caller guarantees that the destination pointer is aligned to that boundary.
				5133	</p>
				5134
				5135	<h5>Semantics:</h5>
				5136
				5137	<p>
				5138	The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
				5139	the
				5140	destination location. If the argument is known to be aligned to some boundary,
				5141	this can be specified as the fourth argument, otherwise it should be set to 0 or
				5142	1.
				5143	</p>
				5144	</div>
				5145
				5146
				5147	<!-- _______________________________________________________________________ -->
				5148	<div class="doc_subsubsection">
				5149	<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
				5150	</div>
				5151
				5152	<div class="doc_text">
				5153
				5154	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5155	<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]	5156	floating point or vector of floating point type. Not all targets support all
				5157	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5158	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5159	declare float @llvm.sqrt.f32(float %Val)
				5160	declare double @llvm.sqrt.f64(double %Val)
				5161	declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
				5162	declare fp128 @llvm.sqrt.f128(fp128 %Val)
				5163	declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5164	</pre>
				5165
				5166	<h5>Overview:</h5>
				5167
				5168	<p>
				5169	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]	5170	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]	5171	<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]	5172	negative numbers other than -0.0 (which allows for better optimization, because
				5173	there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
				5174	defined to return -0.0 like IEEE sqrt.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5175	</p>
				5176
				5177	<h5>Arguments:</h5>
				5178
				5179	<p>
				5180	The argument and return value are floating point numbers of the same type.
				5181	</p>
				5182
				5183	<h5>Semantics:</h5>
				5184
				5185	<p>
				5186	This function returns the sqrt of the specified operand if it is a nonnegative
				5187	floating point number.
				5188	</p>
				5189	</div>
				5190
				5191	<!-- _______________________________________________________________________ -->
				5192	<div class="doc_subsubsection">
				5193	<a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
				5194	</div>
				5195
				5196	<div class="doc_text">
				5197
				5198	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5199	<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]	5200	floating point or vector of floating point type. Not all targets support all
				5201	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5202	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5203	declare float @llvm.powi.f32(float %Val, i32 %power)
				5204	declare double @llvm.powi.f64(double %Val, i32 %power)
				5205	declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
				5206	declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
				5207	declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5208	</pre>
				5209
				5210	<h5>Overview:</h5>
				5211
				5212	<p>
				5213	The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
				5214	specified (positive or negative) power. The order of evaluation of
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5215	multiplications is not defined. When a vector of floating point type is
				5216	used, the second argument remains a scalar integer value.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5217	</p>
				5218
				5219	<h5>Arguments:</h5>
				5220
				5221	<p>
				5222	The second argument is an integer power, and the first is a value to raise to
				5223	that power.
				5224	</p>
				5225
				5226	<h5>Semantics:</h5>
				5227
				5228	<p>
				5229	This function returns the first value raised to the second power with an
				5230	unspecified sequence of rounding operations.</p>
				5231	</div>
				5232
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5233	<!-- _______________________________________________________________________ -->
				5234	<div class="doc_subsubsection">
				5235	<a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
				5236	</div>
				5237
				5238	<div class="doc_text">
				5239
				5240	<h5>Syntax:</h5>
				5241	<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
				5242	floating point or vector of floating point type. Not all targets support all
				5243	types however.
				5244	<pre>
				5245	declare float @llvm.sin.f32(float %Val)
				5246	declare double @llvm.sin.f64(double %Val)
				5247	declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
				5248	declare fp128 @llvm.sin.f128(fp128 %Val)
				5249	declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
				5250	</pre>
				5251
				5252	<h5>Overview:</h5>
				5253
				5254	<p>
				5255	The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
				5256	</p>
				5257
				5258	<h5>Arguments:</h5>
				5259
				5260	<p>
				5261	The argument and return value are floating point numbers of the same type.
				5262	</p>
				5263
				5264	<h5>Semantics:</h5>
				5265
				5266	<p>
				5267	This function returns the sine of the specified operand, returning the
				5268	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]	5269	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5270	</div>
				5271
				5272	<!-- _______________________________________________________________________ -->
				5273	<div class="doc_subsubsection">
				5274	<a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
				5275	</div>
				5276
				5277	<div class="doc_text">
				5278
				5279	<h5>Syntax:</h5>
				5280	<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
				5281	floating point or vector of floating point type. Not all targets support all
				5282	types however.
				5283	<pre>
				5284	declare float @llvm.cos.f32(float %Val)
				5285	declare double @llvm.cos.f64(double %Val)
				5286	declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
				5287	declare fp128 @llvm.cos.f128(fp128 %Val)
				5288	declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
				5289	</pre>
				5290
				5291	<h5>Overview:</h5>
				5292
				5293	<p>
				5294	The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
				5295	</p>
				5296
				5297	<h5>Arguments:</h5>
				5298
				5299	<p>
				5300	The argument and return value are floating point numbers of the same type.
				5301	</p>
				5302
				5303	<h5>Semantics:</h5>
				5304
				5305	<p>
				5306	This function returns the cosine of the specified operand, returning the
				5307	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]	5308	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5309	</div>
				5310
				5311	<!-- _______________________________________________________________________ -->
				5312	<div class="doc_subsubsection">
				5313	<a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
				5314	</div>
				5315
				5316	<div class="doc_text">
				5317
				5318	<h5>Syntax:</h5>
				5319	<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
				5320	floating point or vector of floating point type. Not all targets support all
				5321	types however.
				5322	<pre>
				5323	declare float @llvm.pow.f32(float %Val, float %Power)
				5324	declare double @llvm.pow.f64(double %Val, double %Power)
				5325	declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
				5326	declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
				5327	declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
				5328	</pre>
				5329
				5330	<h5>Overview:</h5>
				5331
				5332	<p>
				5333	The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
				5334	specified (positive or negative) power.
				5335	</p>
				5336
				5337	<h5>Arguments:</h5>
				5338
				5339	<p>
				5340	The second argument is a floating point power, and the first is a value to
				5341	raise to that power.
				5342	</p>
				5343
				5344	<h5>Semantics:</h5>
				5345
				5346	<p>
				5347	This function returns the first value raised to the second power,
				5348	returning the
				5349	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]	5350	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5351	</div>
				5352
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5353
				5354	<!-- ======================================================================= -->
				5355	<div class="doc_subsection">
				5356	<a name="int_manip">Bit Manipulation Intrinsics</a>
				5357	</div>
				5358
				5359	<div class="doc_text">
				5360	<p>
				5361	LLVM provides intrinsics for a few important bit manipulation operations.
				5362	These allow efficient code generation for some algorithms.
				5363	</p>
				5364
				5365	</div>
				5366
				5367	<!-- _______________________________________________________________________ -->
				5368	<div class="doc_subsubsection">
				5369	<a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
				5370	</div>
				5371
				5372	<div class="doc_text">
				5373
				5374	<h5>Syntax:</h5>
				5375	<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]	5376	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]	5377	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5378	declare i16 @llvm.bswap.i16(i16 <id>)
				5379	declare i32 @llvm.bswap.i32(i32 <id>)
				5380	declare i64 @llvm.bswap.i64(i64 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5381	</pre>
				5382
				5383	<h5>Overview:</h5>
				5384
				5385	<p>
				5386	The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
				5387	values with an even number of bytes (positive multiple of 16 bits). These are
				5388	useful for performing operations on data that is not in the target's native
				5389	byte order.
				5390	</p>
				5391
				5392	<h5>Semantics:</h5>
				5393
				5394	<p>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5395	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]	5396	and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
				5397	intrinsic returns an i32 value that has the four bytes of the input i32
				5398	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]	5399	i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
				5400	<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5401	additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
				5402	</p>
				5403
				5404	</div>
				5405
				5406	<!-- _______________________________________________________________________ -->
				5407	<div class="doc_subsubsection">
				5408	<a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
				5409	</div>
				5410
				5411	<div class="doc_text">
				5412
				5413	<h5>Syntax:</h5>
				5414	<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
				5415	width. Not all targets support all bit widths however.
				5416	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5417	declare i8 @llvm.ctpop.i8 (i8 <src>)
				5418	declare i16 @llvm.ctpop.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5419	declare i32 @llvm.ctpop.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5420	declare i64 @llvm.ctpop.i64(i64 <src>)
				5421	declare i256 @llvm.ctpop.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5422	</pre>
				5423
				5424	<h5>Overview:</h5>
				5425
				5426	<p>
				5427	The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
				5428	value.
				5429	</p>
				5430
				5431	<h5>Arguments:</h5>
				5432
				5433	<p>
				5434	The only argument is the value to be counted. The argument may be of any
				5435	integer type. The return type must match the argument type.
				5436	</p>
				5437
				5438	<h5>Semantics:</h5>
				5439
				5440	<p>
				5441	The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
				5442	</p>
				5443	</div>
				5444
				5445	<!-- _______________________________________________________________________ -->
				5446	<div class="doc_subsubsection">
				5447	<a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
				5448	</div>
				5449
				5450	<div class="doc_text">
				5451
				5452	<h5>Syntax:</h5>
				5453	<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
				5454	integer bit width. Not all targets support all bit widths however.
				5455	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5456	declare i8 @llvm.ctlz.i8 (i8 <src>)
				5457	declare i16 @llvm.ctlz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5458	declare i32 @llvm.ctlz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5459	declare i64 @llvm.ctlz.i64(i64 <src>)
				5460	declare i256 @llvm.ctlz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5461	</pre>
				5462
				5463	<h5>Overview:</h5>
				5464
				5465	<p>
				5466	The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
				5467	leading zeros in a variable.
				5468	</p>
				5469
				5470	<h5>Arguments:</h5>
				5471
				5472	<p>
				5473	The only argument is the value to be counted. The argument may be of any
				5474	integer type. The return type must match the argument type.
				5475	</p>
				5476
				5477	<h5>Semantics:</h5>
				5478
				5479	<p>
				5480	The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
				5481	in a variable. If the src == 0 then the result is the size in bits of the type
				5482	of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
				5483	</p>
				5484	</div>
				5485
				5486
				5487
				5488	<!-- _______________________________________________________________________ -->
				5489	<div class="doc_subsubsection">
				5490	<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
				5491	</div>
				5492
				5493	<div class="doc_text">
				5494
				5495	<h5>Syntax:</h5>
				5496	<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
				5497	integer bit width. Not all targets support all bit widths however.
				5498	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5499	declare i8 @llvm.cttz.i8 (i8 <src>)
				5500	declare i16 @llvm.cttz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5501	declare i32 @llvm.cttz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5502	declare i64 @llvm.cttz.i64(i64 <src>)
				5503	declare i256 @llvm.cttz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5504	</pre>
				5505
				5506	<h5>Overview:</h5>
				5507
				5508	<p>
				5509	The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
				5510	trailing zeros.
				5511	</p>
				5512
				5513	<h5>Arguments:</h5>
				5514
				5515	<p>
				5516	The only argument is the value to be counted. The argument may be of any
				5517	integer type. The return type must match the argument type.
				5518	</p>
				5519
				5520	<h5>Semantics:</h5>
				5521
				5522	<p>
				5523	The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
				5524	in a variable. If the src == 0 then the result is the size in bits of the type
				5525	of src. For example, <tt>llvm.cttz(2) = 1</tt>.
				5526	</p>
				5527	</div>
				5528
				5529	<!-- _______________________________________________________________________ -->
				5530	<div class="doc_subsubsection">
				5531	<a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
				5532	</div>
				5533
				5534	<div class="doc_text">
				5535
				5536	<h5>Syntax:</h5>
				5537	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
				5538	on any integer bit width.
				5539	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5540	declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
				5541	declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5542	</pre>
				5543
				5544	<h5>Overview:</h5>
				5545	<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
				5546	range of bits from an integer value and returns them in the same bit width as
				5547	the original value.</p>
				5548
				5549	<h5>Arguments:</h5>
				5550	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5551	any bit width but they must have the same bit width. The second and third
				5552	arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
				5553
				5554	<h5>Semantics:</h5>
				5555	<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
				5556	of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
				5557	<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
				5558	operates in forward mode.</p>
				5559	<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
				5560	right by <tt>%loBit</tt> bits and then ANDing it with a mask with
				5561	only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
				5562	<ol>
				5563	<li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
				5564	by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
				5565	<li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
				5566	to determine the number of bits to retain.</li>
				5567	<li>A mask of the retained bits is created by shifting a -1 value.</li>
				5568	<li>The mask is ANDed with <tt>%val</tt> to produce the result.
				5569	</ol>
				5570	<p>In reverse mode, a similar computation is made except that the bits are
				5571	returned in the reverse order. So, for example, if <tt>X</tt> has the value
				5572	<tt>i16 0x0ACF (101011001111)</tt> and we apply
				5573	<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
				5574	<tt>i16 0x0026 (000000100110)</tt>.</p>
				5575	</div>
				5576
				5577	<div class="doc_subsubsection">
				5578	<a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
				5579	</div>
				5580
				5581	<div class="doc_text">
				5582
				5583	<h5>Syntax:</h5>
				5584	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
				5585	on any integer bit width.
				5586	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5587	declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
				5588	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]	5589	</pre>
				5590
				5591	<h5>Overview:</h5>
				5592	<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
				5593	of bits in an integer value with another integer value. It returns the integer
				5594	with the replaced bits.</p>
				5595
				5596	<h5>Arguments:</h5>
				5597	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5598	any bit width but they must have the same bit width. <tt>%val</tt> is the value
				5599	whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
				5600	integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
				5601	type since they specify only a bit index.</p>
				5602
				5603	<h5>Semantics:</h5>
				5604	<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
				5605	of operation: forwards and reverse. If <tt>%lo</tt> is greater than
				5606	<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
				5607	operates in forward mode.</p>
				5608	<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
				5609	truncating it down to the size of the replacement area or zero extending it
				5610	up to that size.</p>
				5611	<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
				5612	are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
				5613	in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
				5614	to the <tt>%hi</tt>th bit.
				5615	<p>In reverse mode, a similar computation is made except that the bits are
				5616	reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
				5617	<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
				5618	<h5>Examples:</h5>
				5619	<pre>
				5620	llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
				5621	llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
				5622	llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F
				5623	llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
				5624	llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
				5625	</pre>
				5626	</div>
				5627
				5628	<!-- ======================================================================= -->
				5629	<div class="doc_subsection">
				5630	<a name="int_debugger">Debugger Intrinsics</a>
				5631	</div>
				5632
				5633	<div class="doc_text">
				5634	<p>
				5635	The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
				5636	are described in the <a
				5637	href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
				5638	Debugging</a> document.
				5639	</p>
				5640	</div>
				5641
				5642
				5643	<!-- ======================================================================= -->
				5644	<div class="doc_subsection">
				5645	<a name="int_eh">Exception Handling Intrinsics</a>
				5646	</div>
				5647
				5648	<div class="doc_text">
				5649	<p> The LLVM exception handling intrinsics (which all start with
				5650	<tt>llvm.eh.</tt> prefix), are described in the <a
				5651	href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
				5652	Handling</a> document. </p>
				5653	</div>
				5654
				5655	<!-- ======================================================================= -->
				5656	<div class="doc_subsection">
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5657	<a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5658	</div>
				5659
				5660	<div class="doc_text">
				5661	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5662	This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5663	the <tt>nest</tt> attribute, from a function. The result is a callable
				5664	function pointer lacking the nest parameter - the caller does not need
				5665	to provide a value for it. Instead, the value to use is stored in
				5666	advance in a "trampoline", a block of memory usually allocated
				5667	on the stack, which also contains code to splice the nest value into the
				5668	argument list. This is used to implement the GCC nested function address
				5669	extension.
				5670	</p>
				5671	<p>
				5672	For example, if the function is
				5673	<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]	5674	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]	5675	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5676	%tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
				5677	%tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
				5678	%p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8), i8 %nval )
				5679	%fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5680	</pre>
Bill Wendling	e262b4c	2007-09-22 09:23:55 +0000	[diff] [blame]	5681	<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
				5682	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]	5683	</div>
				5684
				5685	<!-- _______________________________________________________________________ -->
				5686	<div class="doc_subsubsection">
				5687	<a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
				5688	</div>
				5689	<div class="doc_text">
				5690	<h5>Syntax:</h5>
				5691	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5692	declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5693	</pre>
				5694	<h5>Overview:</h5>
				5695	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5696	This fills the memory pointed to by <tt>tramp</tt> with code
				5697	and returns a function pointer suitable for executing it.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5698	</p>
				5699	<h5>Arguments:</h5>
				5700	<p>
				5701	The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
				5702	pointers. The <tt>tramp</tt> argument must point to a sufficiently large
				5703	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]	5704	intrinsic. Note that the size and the alignment are target-specific - LLVM
				5705	currently provides no portable way of determining them, so a front-end that
				5706	generates this intrinsic needs to have some target-specific knowledge.
				5707	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]	5708	</p>
				5709	<h5>Semantics:</h5>
				5710	<p>
				5711	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]	5712	dependent code, turning it into a function. A pointer to this function is
				5713	returned, but needs to be bitcast to an
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5714	<a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5715	before being called. The new function's signature is the same as that of
				5716	<tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
				5717	removed. At most one such <tt>nest</tt> argument is allowed, and it must be
				5718	of pointer type. Calling the new function is equivalent to calling
				5719	<tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
				5720	missing <tt>nest</tt> argument. If, after calling
				5721	<tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
				5722	modified, then the effect of any later call to the returned function pointer is
				5723	undefined.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5724	</p>
				5725	</div>
				5726
				5727	<!-- ======================================================================= -->
				5728	<div class="doc_subsection">
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5729	<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
				5730	</div>
				5731
				5732	<div class="doc_text">
				5733	<p>
				5734	These intrinsic functions expand the "universal IR" of LLVM to represent
				5735	hardware constructs for atomic operations and memory synchronization. This
				5736	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]	5737	is aimed at a low enough level to allow any programming models or APIs
				5738	(Application Programming Interfaces) which
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5739	need atomic behaviors to map cleanly onto it. It is also modeled primarily on
				5740	hardware behavior. Just as hardware provides a "universal IR" for source
				5741	languages, it also provides a starting point for developing a "universal"
				5742	atomic operation and synchronization IR.
				5743	</p>
				5744	<p>
				5745	These do <em>not</em> form an API such as high-level threading libraries,
				5746	software transaction memory systems, atomic primitives, and intrinsic
				5747	functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
				5748	application libraries. The hardware interface provided by LLVM should allow
				5749	a clean implementation of all of these APIs and parallel programming models.
				5750	No one model or paradigm should be selected above others unless the hardware
				5751	itself ubiquitously does so.
				5752
				5753	</p>
				5754	</div>
				5755
				5756	<!-- _______________________________________________________________________ -->
				5757	<div class="doc_subsubsection">
				5758	<a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
				5759	</div>
				5760	<div class="doc_text">
				5761	<h5>Syntax:</h5>
				5762	<pre>
				5763	declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>,
				5764	i1 <device> )
				5765
				5766	</pre>
				5767	<h5>Overview:</h5>
				5768	<p>
				5769	The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
				5770	specific pairs of memory access types.
				5771	</p>
				5772	<h5>Arguments:</h5>
				5773	<p>
				5774	The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
				5775	The first four arguments enables a specific barrier as listed below. The fith
				5776	argument specifies that the barrier applies to io or device or uncached memory.
				5777
				5778	</p>
				5779	<ul>
				5780	<li><tt>ll</tt>: load-load barrier</li>
				5781	<li><tt>ls</tt>: load-store barrier</li>
				5782	<li><tt>sl</tt>: store-load barrier</li>
				5783	<li><tt>ss</tt>: store-store barrier</li>
				5784	<li><tt>device</tt>: barrier applies to device and uncached memory also.
				5785	</ul>
				5786	<h5>Semantics:</h5>
				5787	<p>
				5788	This intrinsic causes the system to enforce some ordering constraints upon
				5789	the loads and stores of the program. This barrier does not indicate
				5790	<em>when</em> any events will occur, it only enforces an <em>order</em> in
				5791	which they occur. For any of the specified pairs of load and store operations
				5792	(f.ex. load-load, or store-load), all of the first operations preceding the
				5793	barrier will complete before any of the second operations succeeding the
				5794	barrier begin. Specifically the semantics for each pairing is as follows:
				5795	</p>
				5796	<ul>
				5797	<li><tt>ll</tt>: All loads before the barrier must complete before any load
				5798	after the barrier begins.</li>
				5799
				5800	<li><tt>ls</tt>: All loads before the barrier must complete before any
				5801	store after the barrier begins.</li>
				5802	<li><tt>ss</tt>: All stores before the barrier must complete before any
				5803	store after the barrier begins.</li>
				5804	<li><tt>sl</tt>: All stores before the barrier must complete before any
				5805	load after the barrier begins.</li>
				5806	</ul>
				5807	<p>
				5808	These semantics are applied with a logical "and" behavior when more than one
				5809	is enabled in a single memory barrier intrinsic.
				5810	</p>
				5811	<p>
				5812	Backends may implement stronger barriers than those requested when they do not
				5813	support as fine grained a barrier as requested. Some architectures do not
				5814	need all types of barriers and on such architectures, these become noops.
				5815	</p>
				5816	<h5>Example:</h5>
				5817	<pre>
				5818	%ptr = malloc i32
				5819	store i32 4, %ptr
				5820
				5821	%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
				5822	call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
				5823	<i>; guarantee the above finishes</i>
				5824	store i32 8, %ptr <i>; before this begins</i>
				5825	</pre>
				5826	</div>
				5827
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5828	<!-- _______________________________________________________________________ -->
				5829	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5830	<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]	5831	</div>
				5832	<div class="doc_text">
				5833	<h5>Syntax:</h5>
				5834	<p>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5835	This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
				5836	any integer bit width and for different address spaces. Not all targets
				5837	support all bit widths however.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5838
				5839	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5840	declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
				5841	declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
				5842	declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
				5843	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]	5844
				5845	</pre>
				5846	<h5>Overview:</h5>
				5847	<p>
				5848	This loads a value in memory and compares it to a given value. If they are
				5849	equal, it stores a new value into the memory.
				5850	</p>
				5851	<h5>Arguments:</h5>
				5852	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5853	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]	5854	well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
				5855	same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
				5856	this integer type. While any bit width integer may be used, targets may only
				5857	lower representations they support in hardware.
				5858
				5859	</p>
				5860	<h5>Semantics:</h5>
				5861	<p>
				5862	This entire intrinsic must be executed atomically. It first loads the value
				5863	in memory pointed to by <tt>ptr</tt> and compares it with the value
				5864	<tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
				5865	loaded value is yielded in all cases. This provides the equivalent of an
				5866	atomic compare-and-swap operation within the SSA framework.
				5867	</p>
				5868	<h5>Examples:</h5>
				5869
				5870	<pre>
				5871	%ptr = malloc i32
				5872	store i32 4, %ptr
				5873
				5874	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5875	%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]	5876	<i>; yields {i32}:result1 = 4</i>
				5877	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5878	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5879
				5880	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5881	%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]	5882	<i>; yields {i32}:result2 = 8</i>
				5883	%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
				5884
				5885	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
				5886	</pre>
				5887	</div>
				5888
				5889	<!-- _______________________________________________________________________ -->
				5890	<div class="doc_subsubsection">
				5891	<a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
				5892	</div>
				5893	<div class="doc_text">
				5894	<h5>Syntax:</h5>
				5895
				5896	<p>
				5897	This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
				5898	integer bit width. Not all targets support all bit widths however.</p>
				5899	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5900	declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
				5901	declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
				5902	declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
				5903	declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5904
				5905	</pre>
				5906	<h5>Overview:</h5>
				5907	<p>
				5908	This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
				5909	the value from memory. It then stores the value in <tt>val</tt> in the memory
				5910	at <tt>ptr</tt>.
				5911	</p>
				5912	<h5>Arguments:</h5>
				5913
				5914	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5915	The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5916	<tt>val</tt> argument and the result must be integers of the same bit width.
				5917	The first argument, <tt>ptr</tt>, must be a pointer to a value of this
				5918	integer type. The targets may only lower integer representations they
				5919	support.
				5920	</p>
				5921	<h5>Semantics:</h5>
				5922	<p>
				5923	This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
				5924	stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
				5925	equivalent of an atomic swap operation within the SSA framework.
				5926
				5927	</p>
				5928	<h5>Examples:</h5>
				5929	<pre>
				5930	%ptr = malloc i32
				5931	store i32 4, %ptr
				5932
				5933	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5934	%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5935	<i>; yields {i32}:result1 = 4</i>
				5936	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5937	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5938
				5939	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5940	%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5941	<i>; yields {i32}:result2 = 8</i>
				5942
				5943	%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
				5944	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
				5945	</pre>
				5946	</div>
				5947
				5948	<!-- _______________________________________________________________________ -->
				5949	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5950	<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]	5951
				5952	</div>
				5953	<div class="doc_text">
				5954	<h5>Syntax:</h5>
				5955	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5956	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]	5957	integer bit width. Not all targets support all bit widths however.</p>
				5958	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5959	declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
				5960	declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
				5961	declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
				5962	declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5963
				5964	</pre>
				5965	<h5>Overview:</h5>
				5966	<p>
				5967	This intrinsic adds <tt>delta</tt> to the value stored in memory at
				5968	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				5969	</p>
				5970	<h5>Arguments:</h5>
				5971	<p>
				5972
				5973	The intrinsic takes two arguments, the first a pointer to an integer value
				5974	and the second an integer value. The result is also an integer value. These
				5975	integer types can have any bit width, but they must all have the same bit
				5976	width. The targets may only lower integer representations they support.
				5977	</p>
				5978	<h5>Semantics:</h5>
				5979	<p>
				5980	This intrinsic does a series of operations atomically. It first loads the
				5981	value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
				5982	to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				5983	</p>
				5984
				5985	<h5>Examples:</h5>
				5986	<pre>
				5987	%ptr = malloc i32
				5988	store i32 4, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5989	%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]	5990	<i>; yields {i32}:result1 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5991	%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]	5992	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5993	%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]	5994	<i>; yields {i32}:result3 = 10</i>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5995	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5996	</pre>
				5997	</div>
				5998
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5999	<!-- _______________________________________________________________________ -->
				6000	<div class="doc_subsubsection">
				6001	<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
				6002
				6003	</div>
				6004	<div class="doc_text">
				6005	<h5>Syntax:</h5>
				6006	<p>
				6007	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]	6008	any integer bit width and for different address spaces. Not all targets
				6009	support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6010	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6011	declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
				6012	declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
				6013	declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
				6014	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]	6015
				6016	</pre>
				6017	<h5>Overview:</h5>
				6018	<p>
				6019	This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
				6020	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6021	</p>
				6022	<h5>Arguments:</h5>
				6023	<p>
				6024
				6025	The intrinsic takes two arguments, the first a pointer to an integer value
				6026	and the second an integer value. The result is also an integer value. These
				6027	integer types can have any bit width, but they must all have the same bit
				6028	width. The targets may only lower integer representations they support.
				6029	</p>
				6030	<h5>Semantics:</h5>
				6031	<p>
				6032	This intrinsic does a series of operations atomically. It first loads the
				6033	value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
				6034	result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6035	</p>
				6036
				6037	<h5>Examples:</h5>
				6038	<pre>
				6039	%ptr = malloc i32
				6040	store i32 8, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6041	%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]	6042	<i>; yields {i32}:result1 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6043	%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]	6044	<i>; yields {i32}:result2 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6045	%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]	6046	<i>; yields {i32}:result3 = 2</i>
				6047	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
				6048	</pre>
				6049	</div>
				6050
				6051	<!-- _______________________________________________________________________ -->
				6052	<div class="doc_subsubsection">
				6053	<a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
				6054	<a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
				6055	<a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
				6056	<a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
				6057
				6058	</div>
				6059	<div class="doc_text">
				6060	<h5>Syntax:</h5>
				6061	<p>
				6062	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
				6063	<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]	6064	<tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
				6065	address spaces. Not all targets support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6066	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6067	declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
				6068	declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
				6069	declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
				6070	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]	6071
				6072	</pre>
				6073
				6074	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6075	declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
				6076	declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
				6077	declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
				6078	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]	6079
				6080	</pre>
				6081
				6082	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6083	declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
				6084	declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
				6085	declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
				6086	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]	6087
				6088	</pre>
				6089
				6090	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6091	declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
				6092	declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
				6093	declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
				6094	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]	6095
				6096	</pre>
				6097	<h5>Overview:</h5>
				6098	<p>
				6099	These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
				6100	the value stored in memory at <tt>ptr</tt>. It yields the original value
				6101	at <tt>ptr</tt>.
				6102	</p>
				6103	<h5>Arguments:</h5>
				6104	<p>
				6105
				6106	These intrinsics take two arguments, the first a pointer to an integer value
				6107	and the second an integer value. The result is also an integer value. These
				6108	integer types can have any bit width, but they must all have the same bit
				6109	width. The targets may only lower integer representations they support.
				6110	</p>
				6111	<h5>Semantics:</h5>
				6112	<p>
				6113	These intrinsics does a series of operations atomically. They first load the
				6114	value stored at <tt>ptr</tt>. They then do the bitwise operation
				6115	<tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
				6116	value stored at <tt>ptr</tt>.
				6117	</p>
				6118
				6119	<h5>Examples:</h5>
				6120	<pre>
				6121	%ptr = malloc i32
				6122	store i32 0x0F0F, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6123	%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]	6124	<i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6125	%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]	6126	<i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6127	%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]	6128	<i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6129	%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]	6130	<i>; yields {i32}:result3 = FF</i>
				6131	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
				6132	</pre>
				6133	</div>
				6134
				6135
				6136	<!-- _______________________________________________________________________ -->
				6137	<div class="doc_subsubsection">
				6138	<a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
				6139	<a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
				6140	<a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
				6141	<a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
				6142
				6143	</div>
				6144	<div class="doc_text">
				6145	<h5>Syntax:</h5>
				6146	<p>
				6147	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
				6148	<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]	6149	<tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
				6150	address spaces. Not all targets
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6151	support all bit widths however.</p>
				6152	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6153	declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
				6154	declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
				6155	declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
				6156	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]	6157
				6158	</pre>
				6159
				6160	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6161	declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
				6162	declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
				6163	declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
				6164	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]	6165
				6166	</pre>
				6167
				6168	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6169	declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
				6170	declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
				6171	declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
				6172	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]	6173
				6174	</pre>
				6175
				6176	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6177	declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
				6178	declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
				6179	declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
				6180	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]	6181
				6182	</pre>
				6183	<h5>Overview:</h5>
				6184	<p>
				6185	These intrinsics takes the signed or unsigned minimum or maximum of
				6186	<tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
				6187	original value at <tt>ptr</tt>.
				6188	</p>
				6189	<h5>Arguments:</h5>
				6190	<p>
				6191
				6192	These intrinsics take two arguments, the first a pointer to an integer value
				6193	and the second an integer value. The result is also an integer value. These
				6194	integer types can have any bit width, but they must all have the same bit
				6195	width. The targets may only lower integer representations they support.
				6196	</p>
				6197	<h5>Semantics:</h5>
				6198	<p>
				6199	These intrinsics does a series of operations atomically. They first load the
				6200	value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
				6201	<tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
				6202	the original value stored at <tt>ptr</tt>.
				6203	</p>
				6204
				6205	<h5>Examples:</h5>
				6206	<pre>
				6207	%ptr = malloc i32
				6208	store i32 7, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6209	%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]	6210	<i>; yields {i32}:result0 = 7</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6211	%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]	6212	<i>; yields {i32}:result1 = -2</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6213	%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]	6214	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6215	%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]	6216	<i>; yields {i32}:result3 = 8</i>
				6217	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
				6218	</pre>
				6219	</div>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6220
				6221	<!-- ======================================================================= -->
				6222	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6223	<a name="int_general">General Intrinsics</a>
				6224	</div>
				6225
				6226	<div class="doc_text">
				6227	<p> This class of intrinsics is designed to be generic and has
				6228	no specific purpose. </p>
				6229	</div>
				6230
				6231	<!-- _______________________________________________________________________ -->
				6232	<div class="doc_subsubsection">
				6233	<a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
				6234	</div>
				6235
				6236	<div class="doc_text">
				6237
				6238	<h5>Syntax:</h5>
				6239	<pre>
				6240	declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> )
				6241	</pre>
				6242
				6243	<h5>Overview:</h5>
				6244
				6245	<p>
				6246	The '<tt>llvm.var.annotation</tt>' intrinsic
				6247	</p>
				6248
				6249	<h5>Arguments:</h5>
				6250
				6251	<p>
				6252	The first argument is a pointer to a value, the second is a pointer to a
				6253	global string, the third is a pointer to a global string which is the source
				6254	file name, and the last argument is the line number.
				6255	</p>
				6256
				6257	<h5>Semantics:</h5>
				6258
				6259	<p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6260	This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6261	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]	6262	annotations. These have no other defined use, they are ignored by code
				6263	generation and optimization.
				6264	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6265	</div>
				6266
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6267	<!-- _______________________________________________________________________ -->
				6268	<div class="doc_subsubsection">
Tanya Lattner	c9869b1	2007-09-21 23:57:59 +0000	[diff] [blame]	6269	<a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6270	</div>
				6271
				6272	<div class="doc_text">
				6273
				6274	<h5>Syntax:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6275	<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
				6276	any integer bit width.
				6277	</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6278	<pre>
Tanya Lattner	09161fe	2007-09-22 00:03:01 +0000	[diff] [blame]	6279	declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
				6280	declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
				6281	declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> )
				6282	declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> )
				6283	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]	6284	</pre>
				6285
				6286	<h5>Overview:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6287
				6288	<p>
				6289	The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6290	</p>
				6291
				6292	<h5>Arguments:</h5>
				6293
				6294	<p>
				6295	The first argument is an integer value (result of some expression),
				6296	the second is a pointer to a global string, the third is a pointer to a global
				6297	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]	6298	It returns the value of the first argument.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6299	</p>
				6300
				6301	<h5>Semantics:</h5>
				6302
				6303	<p>
				6304	This intrinsic allows annotations to be put on arbitrary expressions
				6305	with arbitrary strings. This can be useful for special purpose optimizations
				6306	that want to look for these annotations. These have no other defined use, they
				6307	are ignored by code generation and optimization.
				6308	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6309
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6310	<!-- _______________________________________________________________________ -->
				6311	<div class="doc_subsubsection">
				6312	<a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
				6313	</div>
				6314
				6315	<div class="doc_text">
				6316
				6317	<h5>Syntax:</h5>
				6318	<pre>
				6319	declare void @llvm.trap()
				6320	</pre>
				6321
				6322	<h5>Overview:</h5>
				6323
				6324	<p>
				6325	The '<tt>llvm.trap</tt>' intrinsic
				6326	</p>
				6327
				6328	<h5>Arguments:</h5>
				6329
				6330	<p>
				6331	None
				6332	</p>
				6333
				6334	<h5>Semantics:</h5>
				6335
				6336	<p>
				6337	This intrinsics is lowered to the target dependent trap instruction. If the
				6338	target does not have a trap instruction, this intrinsic will be lowered to the
				6339	call of the abort() function.
				6340	</p>
				6341	</div>
				6342
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6343	<!-- *********************************************************************** -->
				6344	<hr>
				6345	<address>
				6346	<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
				6347	src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
				6348	<a href="http://validator.w3.org/check/referer"><img
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	6349	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]	6350
				6351	<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
				6352	<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
				6353	Last modified: $Date$
				6354	</address>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	6355
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6356	</body>
				6357	</html>