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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>
Duncan Sands	d7bfabf	2008-09-12 20:48:21 +0000	[diff] [blame^]	805	@<Name> = alias [Linkage] [Visibility] <AliaseeTy> @<Aliasee>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	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">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	925	<pre>
				926	define void @f() notes(inline=Always) { ... }
				927	define void @f() notes(inline=Always,opt-size) { ... }
				928	define void @f() notes(inline=Never,opt-size) { ... }
				929	define void @f() notes(opt-size) { ... }
				930	</pre>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	931	</div>
				932
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	933	<dl>
				934	<dt><tt>inline=Always</tt></dt>
				935	<dd>This note requests inliner to inline this function irrespective of inlining
				936	size threshold for this function.</dd>
				937
				938	<dt><tt>inline=Never</tt></dt>
				939	<dd>This note requests inliner to never inline this function in any situation.
				940	This note may not be used together with <tt>inline=Always</tt> note.</dd>
				941
				942	<dt><tt>opt-size</tt></dt>
				943	<dd>This note suggests optimization passes and code generator passes to make
				944	choices that help reduce code size.</dd>
				945
				946	</dl>
				947
				948	<p>Any notes that are not documented here are considered invalid notes.</p>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	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">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1398	<td class="left">
				1399	<tt>< { float, i32 (i32)* } ></tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1400	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1401	second element is a <a href="#t_pointer">pointer</a> to a
				1402	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1403	an <tt>i32</tt>.</td>
				1404	</tr>
				1405	</table>
				1406	</div>
				1407
				1408	<!-- _______________________________________________________________________ -->
				1409	<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
				1410	<div class="doc_text">
				1411	<h5>Overview:</h5>
				1412	<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	1413	reference to another object, which must live in memory. Pointer types may have
				1414	an optional address space attribute defining the target-specific numbered
				1415	address space where the pointed-to object resides. The default address space is
				1416	zero.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1417	<h5>Syntax:</h5>
				1418	<pre> <type> *<br></pre>
				1419	<h5>Examples:</h5>
				1420	<table class="layout">
				1421	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1422	<td class="left"><tt>[4x i32]*</tt></td>
				1423	<td class="left">A <a href="#t_pointer">pointer</a> to <a
				1424	href="#t_array">array</a> of four <tt>i32</tt> values.</td>
				1425	</tr>
				1426	<tr class="layout">
				1427	<td class="left"><tt>i32 (i32 ) </tt></td>
				1428	<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]	1429	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]	1430	<tt>i32</tt>.</td>
				1431	</tr>
				1432	<tr class="layout">
				1433	<td class="left"><tt>i32 addrspace(5)*</tt></td>
				1434	<td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
				1435	that resides in address space #5.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1436	</tr>
				1437	</table>
				1438	</div>
				1439
				1440	<!-- _______________________________________________________________________ -->
				1441	<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
				1442	<div class="doc_text">
				1443
				1444	<h5>Overview:</h5>
				1445
				1446	<p>A vector type is a simple derived type that represents a vector
				1447	of elements. Vector types are used when multiple primitive data
				1448	are operated in parallel using a single instruction (SIMD).
				1449	A vector type requires a size (number of
				1450	elements) and an underlying primitive data type. Vectors must have a power
				1451	of two length (1, 2, 4, 8, 16 ...). Vector types are
				1452	considered <a href="#t_firstclass">first class</a>.</p>
				1453
				1454	<h5>Syntax:</h5>
				1455
				1456	<pre>
				1457	< <# elements> x <elementtype> >
				1458	</pre>
				1459
				1460	<p>The number of elements is a constant integer value; elementtype may
				1461	be any integer or floating point type.</p>
				1462
				1463	<h5>Examples:</h5>
				1464
				1465	<table class="layout">
				1466	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1467	<td class="left"><tt><4 x i32></tt></td>
				1468	<td class="left">Vector of 4 32-bit integer values.</td>
				1469	</tr>
				1470	<tr class="layout">
				1471	<td class="left"><tt><8 x float></tt></td>
				1472	<td class="left">Vector of 8 32-bit floating-point values.</td>
				1473	</tr>
				1474	<tr class="layout">
				1475	<td class="left"><tt><2 x i64></tt></td>
				1476	<td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1477	</tr>
				1478	</table>
				1479	</div>
				1480
				1481	<!-- _______________________________________________________________________ -->
				1482	<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
				1483	<div class="doc_text">
				1484
				1485	<h5>Overview:</h5>
				1486
				1487	<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]	1488	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]	1489	In LLVM, opaque types can eventually be resolved to any type (not just a
				1490	structure type).</p>
				1491
				1492	<h5>Syntax:</h5>
				1493
				1494	<pre>
				1495	opaque
				1496	</pre>
				1497
				1498	<h5>Examples:</h5>
				1499
				1500	<table class="layout">
				1501	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1502	<td class="left"><tt>opaque</tt></td>
				1503	<td class="left">An opaque type.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1504	</tr>
				1505	</table>
				1506	</div>
				1507
				1508
				1509	<!-- *********************************************************************** -->
				1510	<div class="doc_section"> <a name="constants">Constants</a> </div>
				1511	<!-- *********************************************************************** -->
				1512
				1513	<div class="doc_text">
				1514
				1515	<p>LLVM has several different basic types of constants. This section describes
				1516	them all and their syntax.</p>
				1517
				1518	</div>
				1519
				1520	<!-- ======================================================================= -->
				1521	<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
				1522
				1523	<div class="doc_text">
				1524
				1525	<dl>
				1526	<dt><b>Boolean constants</b></dt>
				1527
				1528	<dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
				1529	constants of the <tt><a href="#t_primitive">i1</a></tt> type.
				1530	</dd>
				1531
				1532	<dt><b>Integer constants</b></dt>
				1533
				1534	<dd>Standard integers (such as '4') are constants of the <a
				1535	href="#t_integer">integer</a> type. Negative numbers may be used with
				1536	integer types.
				1537	</dd>
				1538
				1539	<dt><b>Floating point constants</b></dt>
				1540
				1541	<dd>Floating point constants use standard decimal notation (e.g. 123.421),
				1542	exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	1543	notation (see below). The assembler requires the exact decimal value of
				1544	a floating-point constant. For example, the assembler accepts 1.25 but
				1545	rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
				1546	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]	1547
				1548	<dt><b>Null pointer constants</b></dt>
				1549
				1550	<dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
				1551	and must be of <a href="#t_pointer">pointer type</a>.</dd>
				1552
				1553	</dl>
				1554
				1555	<p>The one non-intuitive notation for constants is the optional hexadecimal form
				1556	of floating point constants. For example, the form '<tt>double
				1557	0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
				1558	4.5e+15</tt>'. The only time hexadecimal floating point constants are required
				1559	(and the only time that they are generated by the disassembler) is when a
				1560	floating point constant must be emitted but it cannot be represented as a
				1561	decimal floating point number. For example, NaN's, infinities, and other
				1562	special values are represented in their IEEE hexadecimal format so that
				1563	assembly and disassembly do not cause any bits to change in the constants.</p>
				1564
				1565	</div>
				1566
				1567	<!-- ======================================================================= -->
				1568	<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
				1569	</div>
				1570
				1571	<div class="doc_text">
				1572	<p>Aggregate constants arise from aggregation of simple constants
				1573	and smaller aggregate constants.</p>
				1574
				1575	<dl>
				1576	<dt><b>Structure constants</b></dt>
				1577
				1578	<dd>Structure constants are represented with notation similar to structure
				1579	type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner	6c8de96	2007-12-25 20:34:52 +0000	[diff] [blame]	1580	(<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
				1581	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]	1582	must have <a href="#t_struct">structure type</a>, and the number and
				1583	types of elements must match those specified by the type.
				1584	</dd>
				1585
				1586	<dt><b>Array constants</b></dt>
				1587
				1588	<dd>Array constants are represented with notation similar to array type
				1589	definitions (a comma separated list of elements, surrounded by square brackets
				1590	(<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
				1591	constants must have <a href="#t_array">array type</a>, and the number and
				1592	types of elements must match those specified by the type.
				1593	</dd>
				1594
				1595	<dt><b>Vector constants</b></dt>
				1596
				1597	<dd>Vector constants are represented with notation similar to vector type
				1598	definitions (a comma separated list of elements, surrounded by
				1599	less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32 42,
				1600	i32 11, i32 74, i32 100 ></tt>". Vector constants must have <a
				1601	href="#t_vector">vector type</a>, and the number and types of elements must
				1602	match those specified by the type.
				1603	</dd>
				1604
				1605	<dt><b>Zero initialization</b></dt>
				1606
				1607	<dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
				1608	value to zero of <em>any</em> type, including scalar and aggregate types.
				1609	This is often used to avoid having to print large zero initializers (e.g. for
				1610	large arrays) and is always exactly equivalent to using explicit zero
				1611	initializers.
				1612	</dd>
				1613	</dl>
				1614
				1615	</div>
				1616
				1617	<!-- ======================================================================= -->
				1618	<div class="doc_subsection">
				1619	<a name="globalconstants">Global Variable and Function Addresses</a>
				1620	</div>
				1621
				1622	<div class="doc_text">
				1623
				1624	<p>The addresses of <a href="#globalvars">global variables</a> and <a
				1625	href="#functionstructure">functions</a> are always implicitly valid (link-time)
				1626	constants. These constants are explicitly referenced when the <a
				1627	href="#identifiers">identifier for the global</a> is used and always have <a
				1628	href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
				1629	file:</p>
				1630
				1631	<div class="doc_code">
				1632	<pre>
				1633	@X = global i32 17
				1634	@Y = global i32 42
				1635	@Z = global [2 x i32] [ i32 @X, i32* @Y ]
				1636	</pre>
				1637	</div>
				1638
				1639	</div>
				1640
				1641	<!-- ======================================================================= -->
				1642	<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
				1643	<div class="doc_text">
				1644	<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
				1645	no specific value. Undefined values may be of any type and be used anywhere
				1646	a constant is permitted.</p>
				1647
				1648	<p>Undefined values indicate to the compiler that the program is well defined
				1649	no matter what value is used, giving the compiler more freedom to optimize.
				1650	</p>
				1651	</div>
				1652
				1653	<!-- ======================================================================= -->
				1654	<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
				1655	</div>
				1656
				1657	<div class="doc_text">
				1658
				1659	<p>Constant expressions are used to allow expressions involving other constants
				1660	to be used as constants. Constant expressions may be of any <a
				1661	href="#t_firstclass">first class</a> type and may involve any LLVM operation
				1662	that does not have side effects (e.g. load and call are not supported). The
				1663	following is the syntax for constant expressions:</p>
				1664
				1665	<dl>
				1666	<dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
				1667	<dd>Truncate a constant to another type. The bit size of CST must be larger
				1668	than the bit size of TYPE. Both types must be integers.</dd>
				1669
				1670	<dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
				1671	<dd>Zero extend a constant to another type. The bit size of CST must be
				1672	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1673
				1674	<dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
				1675	<dd>Sign extend a constant to another type. The bit size of CST must be
				1676	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1677
				1678	<dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
				1679	<dd>Truncate a floating point constant to another floating point type. The
				1680	size of CST must be larger than the size of TYPE. Both types must be
				1681	floating point.</dd>
				1682
				1683	<dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
				1684	<dd>Floating point extend a constant to another type. The size of CST must be
				1685	smaller or equal to the size of TYPE. Both types must be floating point.</dd>
				1686
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	1687	<dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1688	<dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1689	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1690	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1691	of the same number of elements. If the value won't fit in the integer type,
				1692	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1693
				1694	<dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
				1695	<dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1696	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1697	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1698	of the same number of elements. If the value won't fit in the integer type,
				1699	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1700
				1701	<dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
				1702	<dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1703	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1704	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1705	of the same number of elements. If the value won't fit in the floating point
				1706	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1707
				1708	<dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
				1709	<dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1710	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1711	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1712	of the same number of elements. If the value won't fit in the floating point
				1713	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1714
				1715	<dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
				1716	<dd>Convert a pointer typed constant to the corresponding integer constant
				1717	TYPE must be an integer type. CST must be of pointer type. The CST value is
				1718	zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
				1719
				1720	<dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
				1721	<dd>Convert a integer constant to a pointer constant. TYPE must be a
				1722	pointer type. CST must be of integer type. The CST value is zero extended,
				1723	truncated, or unchanged to make it fit in a pointer size. This one is
				1724	<i>really</i> dangerous!</dd>
				1725
				1726	<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
				1727	<dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
				1728	identical (same number of bits). The conversion is done as if the CST value
				1729	was stored to memory and read back as TYPE. In other words, no bits change
				1730	with this operator, just the type. This can be used for conversion of
				1731	vector types to any other type, as long as they have the same bit width. For
Dan Gohman	7305fa0	2008-09-08 16:45:59 +0000	[diff] [blame]	1732	pointers it is only valid to cast to another pointer type. It is not valid
				1733	to bitcast to or from an aggregate type.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1734	</dd>
				1735
				1736	<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
				1737
				1738	<dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
				1739	constants. As with the <a href="#i_getelementptr">getelementptr</a>
				1740	instruction, the index list may have zero or more indexes, which are required
				1741	to make sense for the type of "CSTPTR".</dd>
				1742
				1743	<dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
				1744
				1745	<dd>Perform the <a href="#i_select">select operation</a> on
				1746	constants.</dd>
				1747
				1748	<dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
				1749	<dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
				1750
				1751	<dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1752	<dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
				1753
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	1754	<dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
				1755	<dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
				1756
				1757	<dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1758	<dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
				1759
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1760	<dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
				1761
				1762	<dd>Perform the <a href="#i_extractelement">extractelement
				1763	operation</a> on constants.
				1764
				1765	<dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
				1766
				1767	<dd>Perform the <a href="#i_insertelement">insertelement
				1768	operation</a> on constants.</dd>
				1769
				1770
				1771	<dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
				1772
				1773	<dd>Perform the <a href="#i_shufflevector">shufflevector
				1774	operation</a> on constants.</dd>
				1775
				1776	<dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
				1777
				1778	<dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
				1779	be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
				1780	binary</a> operations. The constraints on operands are the same as those for
				1781	the corresponding instruction (e.g. no bitwise operations on floating point
				1782	values are allowed).</dd>
				1783	</dl>
				1784	</div>
				1785
				1786	<!-- *********************************************************************** -->
				1787	<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
				1788	<!-- *********************************************************************** -->
				1789
				1790	<!-- ======================================================================= -->
				1791	<div class="doc_subsection">
				1792	<a name="inlineasm">Inline Assembler Expressions</a>
				1793	</div>
				1794
				1795	<div class="doc_text">
				1796
				1797	<p>
				1798	LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
				1799	Module-Level Inline Assembly</a>) through the use of a special value. This
				1800	value represents the inline assembler as a string (containing the instructions
				1801	to emit), a list of operand constraints (stored as a string), and a flag that
				1802	indicates whether or not the inline asm expression has side effects. An example
				1803	inline assembler expression is:
				1804	</p>
				1805
				1806	<div class="doc_code">
				1807	<pre>
				1808	i32 (i32) asm "bswap $0", "=r,r"
				1809	</pre>
				1810	</div>
				1811
				1812	<p>
				1813	Inline assembler expressions may <b>only</b> be used as the callee operand of
				1814	a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
				1815	</p>
				1816
				1817	<div class="doc_code">
				1818	<pre>
				1819	%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
				1820	</pre>
				1821	</div>
				1822
				1823	<p>
				1824	Inline asms with side effects not visible in the constraint list must be marked
				1825	as having side effects. This is done through the use of the
				1826	'<tt>sideeffect</tt>' keyword, like so:
				1827	</p>
				1828
				1829	<div class="doc_code">
				1830	<pre>
				1831	call void asm sideeffect "eieio", ""()
				1832	</pre>
				1833	</div>
				1834
				1835	<p>TODO: The format of the asm and constraints string still need to be
				1836	documented here. Constraints on what can be done (e.g. duplication, moving, etc
				1837	need to be documented).
				1838	</p>
				1839
				1840	</div>
				1841
				1842	<!-- *********************************************************************** -->
				1843	<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
				1844	<!-- *********************************************************************** -->
				1845
				1846	<div class="doc_text">
				1847
				1848	<p>The LLVM instruction set consists of several different
				1849	classifications of instructions: <a href="#terminators">terminator
				1850	instructions</a>, <a href="#binaryops">binary instructions</a>,
				1851	<a href="#bitwiseops">bitwise binary instructions</a>, <a
				1852	href="#memoryops">memory instructions</a>, and <a href="#otherops">other
				1853	instructions</a>.</p>
				1854
				1855	</div>
				1856
				1857	<!-- ======================================================================= -->
				1858	<div class="doc_subsection"> <a name="terminators">Terminator
				1859	Instructions</a> </div>
				1860
				1861	<div class="doc_text">
				1862
				1863	<p>As mentioned <a href="#functionstructure">previously</a>, every
				1864	basic block in a program ends with a "Terminator" instruction, which
				1865	indicates which block should be executed after the current block is
				1866	finished. These terminator instructions typically yield a '<tt>void</tt>'
				1867	value: they produce control flow, not values (the one exception being
				1868	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
				1869	<p>There are six different terminator instructions: the '<a
				1870	href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
				1871	instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
				1872	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
				1873	href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
				1874	href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
				1875
				1876	</div>
				1877
				1878	<!-- _______________________________________________________________________ -->
				1879	<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
				1880	Instruction</a> </div>
				1881	<div class="doc_text">
				1882	<h5>Syntax:</h5>
				1883	<pre> ret <type> <value> <i>; Return a value from a non-void function</i>
				1884	ret void <i>; Return from void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1885	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]	1886	</pre>
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	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1889
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1890	<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
				1891	value) from a function back to the caller.</p>
				1892	<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]	1893	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]	1894	control flow to occur.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1895
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1896	<h5>Arguments:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1897
				1898	<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
				1899	The type of each return value must be a '<a href="#t_firstclass">first
				1900	class</a>' type. Note that a function is not <a href="#wellformed">well
				1901	formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
				1902	function that returns values that do not match the return type of the
				1903	function.</p>
				1904
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1905	<h5>Semantics:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1906
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1907	<p>When the '<tt>ret</tt>' instruction is executed, control flow
				1908	returns back to the calling function's context. If the caller is a "<a
				1909	href="#i_call"><tt>call</tt></a>" instruction, execution continues at
				1910	the instruction after the call. If the caller was an "<a
				1911	href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
				1912	at the beginning of the "normal" destination block. If the instruction
				1913	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]	1914	return value. If the instruction returns multiple values then these
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	1915	values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
				1916	</a>' instruction.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1917
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1918	<h5>Example:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1919
				1920	<pre>
				1921	ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1922	ret void <i>; Return from a void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1923	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]	1924	</pre>
				1925	</div>
				1926	<!-- _______________________________________________________________________ -->
				1927	<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
				1928	<div class="doc_text">
				1929	<h5>Syntax:</h5>
				1930	<pre> br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
				1931	</pre>
				1932	<h5>Overview:</h5>
				1933	<p>The '<tt>br</tt>' instruction is used to cause control flow to
				1934	transfer to a different basic block in the current function. There are
				1935	two forms of this instruction, corresponding to a conditional branch
				1936	and an unconditional branch.</p>
				1937	<h5>Arguments:</h5>
				1938	<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
				1939	single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
				1940	unconditional form of the '<tt>br</tt>' instruction takes a single
				1941	'<tt>label</tt>' value as a target.</p>
				1942	<h5>Semantics:</h5>
				1943	<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
				1944	argument is evaluated. If the value is <tt>true</tt>, control flows
				1945	to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
				1946	control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
				1947	<h5>Example:</h5>
				1948	<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
				1949	href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
				1950	</div>
				1951	<!-- _______________________________________________________________________ -->
				1952	<div class="doc_subsubsection">
				1953	<a name="i_switch">'<tt>switch</tt>' Instruction</a>
				1954	</div>
				1955
				1956	<div class="doc_text">
				1957	<h5>Syntax:</h5>
				1958
				1959	<pre>
				1960	switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
				1961	</pre>
				1962
				1963	<h5>Overview:</h5>
				1964
				1965	<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
				1966	several different places. It is a generalization of the '<tt>br</tt>'
				1967	instruction, allowing a branch to occur to one of many possible
				1968	destinations.</p>
				1969
				1970
				1971	<h5>Arguments:</h5>
				1972
				1973	<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
				1974	comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
				1975	an array of pairs of comparison value constants and '<tt>label</tt>'s. The
				1976	table is not allowed to contain duplicate constant entries.</p>
				1977
				1978	<h5>Semantics:</h5>
				1979
				1980	<p>The <tt>switch</tt> instruction specifies a table of values and
				1981	destinations. When the '<tt>switch</tt>' instruction is executed, this
				1982	table is searched for the given value. If the value is found, control flow is
				1983	transfered to the corresponding destination; otherwise, control flow is
				1984	transfered to the default destination.</p>
				1985
				1986	<h5>Implementation:</h5>
				1987
				1988	<p>Depending on properties of the target machine and the particular
				1989	<tt>switch</tt> instruction, this instruction may be code generated in different
				1990	ways. For example, it could be generated as a series of chained conditional
				1991	branches or with a lookup table.</p>
				1992
				1993	<h5>Example:</h5>
				1994
				1995	<pre>
				1996	<i>; Emulate a conditional br instruction</i>
				1997	%Val = <a href="#i_zext">zext</a> i1 %value to i32
				1998	switch i32 %Val, label %truedest [i32 0, label %falsedest ]
				1999
				2000	<i>; Emulate an unconditional br instruction</i>
				2001	switch i32 0, label %dest [ ]
				2002
				2003	<i>; Implement a jump table:</i>
				2004	switch i32 %val, label %otherwise [ i32 0, label %onzero
				2005	i32 1, label %onone
				2006	i32 2, label %ontwo ]
				2007	</pre>
				2008	</div>
				2009
				2010	<!-- _______________________________________________________________________ -->
				2011	<div class="doc_subsubsection">
				2012	<a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
				2013	</div>
				2014
				2015	<div class="doc_text">
				2016
				2017	<h5>Syntax:</h5>
				2018
				2019	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2020	<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]	2021	to label <normal label> unwind label <exception label>
				2022	</pre>
				2023
				2024	<h5>Overview:</h5>
				2025
				2026	<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
				2027	function, with the possibility of control flow transfer to either the
				2028	'<tt>normal</tt>' label or the
				2029	'<tt>exception</tt>' label. If the callee function returns with the
				2030	"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
				2031	"normal" label. If the callee (or any indirect callees) returns with the "<a
				2032	href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	2033	continued at the dynamically nearest "exception" label. If the callee function
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	2034	returns multiple values then individual return values are only accessible through
				2035	a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2036
				2037	<h5>Arguments:</h5>
				2038
				2039	<p>This instruction requires several arguments:</p>
				2040
				2041	<ol>
				2042	<li>
				2043	The optional "cconv" marker indicates which <a href="#callingconv">calling
				2044	convention</a> the call should use. If none is specified, the call defaults
				2045	to using C calling conventions.
				2046	</li>
				2047	<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
				2048	function value being invoked. In most cases, this is a direct function
				2049	invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
				2050	an arbitrary pointer to function value.
				2051	</li>
				2052
				2053	<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
				2054	function to be invoked. </li>
				2055
				2056	<li>'<tt>function args</tt>': argument list whose types match the function
				2057	signature argument types. If the function signature indicates the function
				2058	accepts a variable number of arguments, the extra arguments can be
				2059	specified. </li>
				2060
				2061	<li>'<tt>normal label</tt>': the label reached when the called function
				2062	executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
				2063
				2064	<li>'<tt>exception label</tt>': the label reached when a callee returns with
				2065	the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
				2066
				2067	</ol>
				2068
				2069	<h5>Semantics:</h5>
				2070
				2071	<p>This instruction is designed to operate as a standard '<tt><a
				2072	href="#i_call">call</a></tt>' instruction in most regards. The primary
				2073	difference is that it establishes an association with a label, which is used by
				2074	the runtime library to unwind the stack.</p>
				2075
				2076	<p>This instruction is used in languages with destructors to ensure that proper
				2077	cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
				2078	exception. Additionally, this is important for implementation of
				2079	'<tt>catch</tt>' clauses in high-level languages that support them.</p>
				2080
				2081	<h5>Example:</h5>
				2082	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2083	%retval = invoke i32 @Test(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>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2085	%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]	2086	unwind label %TestCleanup <i>; {i32}:retval set</i>
				2087	</pre>
				2088	</div>
				2089
				2090
				2091	<!-- _______________________________________________________________________ -->
				2092
				2093	<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
				2094	Instruction</a> </div>
				2095
				2096	<div class="doc_text">
				2097
				2098	<h5>Syntax:</h5>
				2099	<pre>
				2100	unwind
				2101	</pre>
				2102
				2103	<h5>Overview:</h5>
				2104
				2105	<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
				2106	at the first callee in the dynamic call stack which used an <a
				2107	href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
				2108	primarily used to implement exception handling.</p>
				2109
				2110	<h5>Semantics:</h5>
				2111
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	2112	<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]	2113	immediately halt. The dynamic call stack is then searched for the first <a
				2114	href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
				2115	execution continues at the "exceptional" destination block specified by the
				2116	<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
				2117	dynamic call chain, undefined behavior results.</p>
				2118	</div>
				2119
				2120	<!-- _______________________________________________________________________ -->
				2121
				2122	<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
				2123	Instruction</a> </div>
				2124
				2125	<div class="doc_text">
				2126
				2127	<h5>Syntax:</h5>
				2128	<pre>
				2129	unreachable
				2130	</pre>
				2131
				2132	<h5>Overview:</h5>
				2133
				2134	<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
				2135	instruction is used to inform the optimizer that a particular portion of the
				2136	code is not reachable. This can be used to indicate that the code after a
				2137	no-return function cannot be reached, and other facts.</p>
				2138
				2139	<h5>Semantics:</h5>
				2140
				2141	<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
				2142	</div>
				2143
				2144
				2145
				2146	<!-- ======================================================================= -->
				2147	<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
				2148	<div class="doc_text">
				2149	<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]	2150	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]	2151	produce a single value. The operands might represent
				2152	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]	2153	The result value has the same type as its operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2154	<p>There are several different binary operators:</p>
				2155	</div>
				2156	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2157	<div class="doc_subsubsection">
				2158	<a name="i_add">'<tt>add</tt>' Instruction</a>
				2159	</div>
				2160
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2161	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2162
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2163	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2164
				2165	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2166	<result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2167	</pre>
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	<h5>Overview:</h5>
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	<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]	2172
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2173	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2174
				2175	<p>The two arguments to the '<tt>add</tt>' instruction must be <a
				2176	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
				2177	<a href="#t_vector">vector</a> values. Both arguments must have identical
				2178	types.</p>
				2179
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2180	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2181
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2182	<p>The value produced is the integer or floating point sum of the two
				2183	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2184
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2185	<p>If an integer sum has unsigned overflow, the result returned is the
				2186	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2187	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2188
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2189	<p>Because LLVM integers use a two's complement representation, this
				2190	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2191
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2192	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2193
				2194	<pre>
				2195	<result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2196	</pre>
				2197	</div>
				2198	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2199	<div class="doc_subsubsection">
				2200	<a name="i_sub">'<tt>sub</tt>' Instruction</a>
				2201	</div>
				2202
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2203	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2204
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2205	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2206
				2207	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2208	<result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2209	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2212
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2213	<p>The '<tt>sub</tt>' instruction returns the difference of its two
				2214	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2215
				2216	<p>Note that the '<tt>sub</tt>' instruction is used to represent the
				2217	'<tt>neg</tt>' instruction present in most other intermediate
				2218	representations.</p>
				2219
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2220	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2221
				2222	<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
				2223	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2224	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2225	types.</p>
				2226
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2227	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2228
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2229	<p>The value produced is the integer or floating point difference of
				2230	the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2231
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2232	<p>If an integer difference has unsigned overflow, the result returned is the
				2233	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2234	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2235
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2236	<p>Because LLVM integers use a two's complement representation, this
				2237	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2238
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2239	<h5>Example:</h5>
				2240	<pre>
				2241	<result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
				2242	<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
				2243	</pre>
				2244	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2245
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2246	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2247	<div class="doc_subsubsection">
				2248	<a name="i_mul">'<tt>mul</tt>' Instruction</a>
				2249	</div>
				2250
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2251	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2252
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2253	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2254	<pre> <result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2255	</pre>
				2256	<h5>Overview:</h5>
				2257	<p>The '<tt>mul</tt>' instruction returns the product of its two
				2258	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2259
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2260	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2261
				2262	<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
				2263	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2264	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2265	types.</p>
				2266
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2267	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2268
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2269	<p>The value produced is the integer or floating point product of the
				2270	two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2271
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2272	<p>If the result of an integer multiplication has unsigned overflow,
				2273	the result returned is the mathematical result modulo
				2274	2<sup>n</sup>, where n is the bit width of the result.</p>
				2275	<p>Because LLVM integers use a two's complement representation, and the
				2276	result is the same width as the operands, this instruction returns the
				2277	correct result for both signed and unsigned integers. If a full product
				2278	(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
				2279	should be sign-extended or zero-extended as appropriate to the
				2280	width of the full product.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2281	<h5>Example:</h5>
				2282	<pre> <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
				2283	</pre>
				2284	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2285
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2286	<!-- _______________________________________________________________________ -->
				2287	<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
				2288	</a></div>
				2289	<div class="doc_text">
				2290	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2291	<pre> <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2292	</pre>
				2293	<h5>Overview:</h5>
				2294	<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
				2295	operands.</p>
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	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2298
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2299	<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2300	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2301	values. Both arguments must have identical types.</p>
				2302
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2303	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2304
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2305	<p>The value produced is the unsigned integer quotient of the two operands.</p>
				2306	<p>Note that unsigned integer division and signed integer division are distinct
				2307	operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
				2308	<p>Division by zero leads to undefined behavior.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2309	<h5>Example:</h5>
				2310	<pre> <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2311	</pre>
				2312	</div>
				2313	<!-- _______________________________________________________________________ -->
				2314	<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
				2315	</a> </div>
				2316	<div class="doc_text">
				2317	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2318	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2319	<result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2320	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2323
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2324	<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
				2325	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2326
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2327	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2328
				2329	<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
				2330	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2331	values. Both arguments must have identical types.</p>
				2332
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2333	<h5>Semantics:</h5>
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2334	<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]	2335	<p>Note that signed integer division and unsigned integer division are distinct
				2336	operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
				2337	<p>Division by zero leads to undefined behavior. Overflow also leads to
				2338	undefined behavior; this is a rare case, but can occur, for example,
				2339	by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2340	<h5>Example:</h5>
				2341	<pre> <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2342	</pre>
				2343	</div>
				2344	<!-- _______________________________________________________________________ -->
				2345	<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
				2346	Instruction</a> </div>
				2347	<div class="doc_text">
				2348	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2349	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2350	<result> = fdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2351	</pre>
				2352	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2353
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2354	<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
				2355	operands.</p>
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	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2358
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2359	<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2360	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2361	of floating point values. Both arguments must have identical types.</p>
				2362
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2363	<h5>Semantics:</h5>
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	<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]	2366
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2367	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2368
				2369	<pre>
				2370	<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]	2371	</pre>
				2372	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2373
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2374	<!-- _______________________________________________________________________ -->
				2375	<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
				2376	</div>
				2377	<div class="doc_text">
				2378	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2379	<pre> <result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2380	</pre>
				2381	<h5>Overview:</h5>
				2382	<p>The '<tt>urem</tt>' instruction returns the remainder from the
				2383	unsigned division of its two arguments.</p>
				2384	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2385	<p>The two arguments to the '<tt>urem</tt>' instruction must be
				2386	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2387	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2388	<h5>Semantics:</h5>
				2389	<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]	2390	This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2391	<p>Note that unsigned integer remainder and signed integer remainder are
				2392	distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
				2393	<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]	2394	<h5>Example:</h5>
				2395	<pre> <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2396	</pre>
				2397
				2398	</div>
				2399	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2400	<div class="doc_subsubsection">
				2401	<a name="i_srem">'<tt>srem</tt>' Instruction</a>
				2402	</div>
				2403
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2404	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2405
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2406	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2407
				2408	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2409	<result> = srem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2410	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2413
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2414	<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman	3e3fd8c	2007-11-05 23:35:22 +0000	[diff] [blame]	2415	signed division of its two operands. This instruction can also take
				2416	<a href="#t_vector">vector</a> versions of the values in which case
				2417	the elements must be integers.</p>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	2418
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2419	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2420
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2421	<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2422	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2423	values. Both arguments must have identical types.</p>
				2424
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2425	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2426
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2427	<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]	2428	has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
				2429	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]	2430	a value. For more information about the difference, see <a
				2431	href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
				2432	Math Forum</a>. For a table of how this is implemented in various languages,
				2433	please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
				2434	Wikipedia: modulo operation</a>.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2435	<p>Note that signed integer remainder and unsigned integer remainder are
				2436	distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
				2437	<p>Taking the remainder of a division by zero leads to undefined behavior.
				2438	Overflow also leads to undefined behavior; this is a rare case, but can occur,
				2439	for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
				2440	(The remainder doesn't actually overflow, but this rule lets srem be
				2441	implemented using instructions that return both the result of the division
				2442	and the remainder.)</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2443	<h5>Example:</h5>
				2444	<pre> <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2445	</pre>
				2446
				2447	</div>
				2448	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2449	<div class="doc_subsubsection">
				2450	<a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
				2451
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2452	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2453
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2454	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2455	<pre> <result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2456	</pre>
				2457	<h5>Overview:</h5>
				2458	<p>The '<tt>frem</tt>' instruction returns the remainder from the
				2459	division of its two operands.</p>
				2460	<h5>Arguments:</h5>
				2461	<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2462	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2463	of floating point values. Both arguments must have identical types.</p>
				2464
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2465	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2466
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2467	<p>This instruction returns the <i>remainder</i> of a division.
				2468	The remainder has the same sign as the dividend.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2469
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2470	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2471
				2472	<pre>
				2473	<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]	2474	</pre>
				2475	</div>
				2476
				2477	<!-- ======================================================================= -->
				2478	<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
				2479	Operations</a> </div>
				2480	<div class="doc_text">
				2481	<p>Bitwise binary operators are used to do various forms of
				2482	bit-twiddling in a program. They are generally very efficient
				2483	instructions and can commonly be strength reduced from other
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2484	instructions. They require two operands of the same type, execute an operation on them,
				2485	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]	2486	</div>
				2487
				2488	<!-- _______________________________________________________________________ -->
				2489	<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
				2490	Instruction</a> </div>
				2491	<div class="doc_text">
				2492	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2493	<pre> <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2494	</pre>
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	<h5>Overview:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2497
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2498	<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
				2499	the left a specified number of bits.</p>
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	<h5>Arguments:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2502
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2503	<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]	2504	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]	2505	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2506
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2507	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2508
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2509	<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
				2510	where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
				2511	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]	2512
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2513	<h5>Example:</h5><pre>
				2514	<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
				2515	<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
				2516	<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2517	<result> = shl i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2518	</pre>
				2519	</div>
				2520	<!-- _______________________________________________________________________ -->
				2521	<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
				2522	Instruction</a> </div>
				2523	<div class="doc_text">
				2524	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2525	<pre> <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2526	</pre>
				2527
				2528	<h5>Overview:</h5>
				2529	<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
				2530	operand shifted to the right a specified number of bits with zero fill.</p>
				2531
				2532	<h5>Arguments:</h5>
				2533	<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]	2534	<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]	2535	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2536
				2537	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2538
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2539	<p>This instruction always performs a logical shift right operation. The most
				2540	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]	2541	shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
				2542	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]	2543
				2544	<h5>Example:</h5>
				2545	<pre>
				2546	<result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2547	<result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2548	<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2549	<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2550	<result> = lshr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2551	</pre>
				2552	</div>
				2553
				2554	<!-- _______________________________________________________________________ -->
				2555	<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
				2556	Instruction</a> </div>
				2557	<div class="doc_text">
				2558
				2559	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2560	<pre> <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2561	</pre>
				2562
				2563	<h5>Overview:</h5>
				2564	<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
				2565	operand shifted to the right a specified number of bits with sign extension.</p>
				2566
				2567	<h5>Arguments:</h5>
				2568	<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]	2569	<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]	2570	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2571
				2572	<h5>Semantics:</h5>
				2573	<p>This instruction always performs an arithmetic shift right operation,
				2574	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]	2575	of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
				2576	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]	2577	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2578
				2579	<h5>Example:</h5>
				2580	<pre>
				2581	<result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2582	<result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2583	<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2584	<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2585	<result> = ashr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2586	</pre>
				2587	</div>
				2588
				2589	<!-- _______________________________________________________________________ -->
				2590	<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
				2591	Instruction</a> </div>
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	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2594
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2595	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2596
				2597	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2598	<result> = and <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2599	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2602
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2603	<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
				2604	its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2605
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2606	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2607
				2608	<p>The two arguments to the '<tt>and</tt>' instruction must be
				2609	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2610	values. Both arguments must have identical types.</p>
				2611
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2612	<h5>Semantics:</h5>
				2613	<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
				2614	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2615	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2616	<table border="1" cellspacing="0" cellpadding="4">
				2617	<tbody>
				2618	<tr>
				2619	<td>In0</td>
				2620	<td>In1</td>
				2621	<td>Out</td>
				2622	</tr>
				2623	<tr>
				2624	<td>0</td>
				2625	<td>0</td>
				2626	<td>0</td>
				2627	</tr>
				2628	<tr>
				2629	<td>0</td>
				2630	<td>1</td>
				2631	<td>0</td>
				2632	</tr>
				2633	<tr>
				2634	<td>1</td>
				2635	<td>0</td>
				2636	<td>0</td>
				2637	</tr>
				2638	<tr>
				2639	<td>1</td>
				2640	<td>1</td>
				2641	<td>1</td>
				2642	</tr>
				2643	</tbody>
				2644	</table>
				2645	</div>
				2646	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2647	<pre>
				2648	<result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2649	<result> = and i32 15, 40 <i>; yields {i32}:result = 8</i>
				2650	<result> = and i32 4, 8 <i>; yields {i32}:result = 0</i>
				2651	</pre>
				2652	</div>
				2653	<!-- _______________________________________________________________________ -->
				2654	<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
				2655	<div class="doc_text">
				2656	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2657	<pre> <result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2658	</pre>
				2659	<h5>Overview:</h5>
				2660	<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
				2661	or of its two operands.</p>
				2662	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2663
				2664	<p>The two arguments to the '<tt>or</tt>' instruction must be
				2665	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2666	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2667	<h5>Semantics:</h5>
				2668	<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
				2669	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2670	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2671	<table border="1" cellspacing="0" cellpadding="4">
				2672	<tbody>
				2673	<tr>
				2674	<td>In0</td>
				2675	<td>In1</td>
				2676	<td>Out</td>
				2677	</tr>
				2678	<tr>
				2679	<td>0</td>
				2680	<td>0</td>
				2681	<td>0</td>
				2682	</tr>
				2683	<tr>
				2684	<td>0</td>
				2685	<td>1</td>
				2686	<td>1</td>
				2687	</tr>
				2688	<tr>
				2689	<td>1</td>
				2690	<td>0</td>
				2691	<td>1</td>
				2692	</tr>
				2693	<tr>
				2694	<td>1</td>
				2695	<td>1</td>
				2696	<td>1</td>
				2697	</tr>
				2698	</tbody>
				2699	</table>
				2700	</div>
				2701	<h5>Example:</h5>
				2702	<pre> <result> = or i32 4, %var <i>; yields {i32}:result = 4 \| %var</i>
				2703	<result> = or i32 15, 40 <i>; yields {i32}:result = 47</i>
				2704	<result> = or i32 4, 8 <i>; yields {i32}:result = 12</i>
				2705	</pre>
				2706	</div>
				2707	<!-- _______________________________________________________________________ -->
				2708	<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
				2709	Instruction</a> </div>
				2710	<div class="doc_text">
				2711	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2712	<pre> <result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2713	</pre>
				2714	<h5>Overview:</h5>
				2715	<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
				2716	or of its two operands. The <tt>xor</tt> is used to implement the
				2717	"one's complement" operation, which is the "~" operator in C.</p>
				2718	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2719	<p>The two arguments to the '<tt>xor</tt>' instruction must be
				2720	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2721	values. Both arguments must have identical types.</p>
				2722
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2723	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2724
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2725	<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
				2726	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2727	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2728	<table border="1" cellspacing="0" cellpadding="4">
				2729	<tbody>
				2730	<tr>
				2731	<td>In0</td>
				2732	<td>In1</td>
				2733	<td>Out</td>
				2734	</tr>
				2735	<tr>
				2736	<td>0</td>
				2737	<td>0</td>
				2738	<td>0</td>
				2739	</tr>
				2740	<tr>
				2741	<td>0</td>
				2742	<td>1</td>
				2743	<td>1</td>
				2744	</tr>
				2745	<tr>
				2746	<td>1</td>
				2747	<td>0</td>
				2748	<td>1</td>
				2749	</tr>
				2750	<tr>
				2751	<td>1</td>
				2752	<td>1</td>
				2753	<td>0</td>
				2754	</tr>
				2755	</tbody>
				2756	</table>
				2757	</div>
				2758	<p> </p>
				2759	<h5>Example:</h5>
				2760	<pre> <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
				2761	<result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
				2762	<result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
				2763	<result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
				2764	</pre>
				2765	</div>
				2766
				2767	<!-- ======================================================================= -->
				2768	<div class="doc_subsection">
				2769	<a name="vectorops">Vector Operations</a>
				2770	</div>
				2771
				2772	<div class="doc_text">
				2773
				2774	<p>LLVM supports several instructions to represent vector operations in a
				2775	target-independent manner. These instructions cover the element-access and
				2776	vector-specific operations needed to process vectors effectively. While LLVM
				2777	does directly support these vector operations, many sophisticated algorithms
				2778	will want to use target-specific intrinsics to take full advantage of a specific
				2779	target.</p>
				2780
				2781	</div>
				2782
				2783	<!-- _______________________________________________________________________ -->
				2784	<div class="doc_subsubsection">
				2785	<a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
				2786	</div>
				2787
				2788	<div class="doc_text">
				2789
				2790	<h5>Syntax:</h5>
				2791
				2792	<pre>
				2793	<result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
				2794	</pre>
				2795
				2796	<h5>Overview:</h5>
				2797
				2798	<p>
				2799	The '<tt>extractelement</tt>' instruction extracts a single scalar
				2800	element from a vector at a specified index.
				2801	</p>
				2802
				2803
				2804	<h5>Arguments:</h5>
				2805
				2806	<p>
				2807	The first operand of an '<tt>extractelement</tt>' instruction is a
				2808	value of <a href="#t_vector">vector</a> type. The second operand is
				2809	an index indicating the position from which to extract the element.
				2810	The index may be a variable.</p>
				2811
				2812	<h5>Semantics:</h5>
				2813
				2814	<p>
				2815	The result is a scalar of the same type as the element type of
				2816	<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
				2817	<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
				2818	results are undefined.
				2819	</p>
				2820
				2821	<h5>Example:</h5>
				2822
				2823	<pre>
				2824	%result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
				2825	</pre>
				2826	</div>
				2827
				2828
				2829	<!-- _______________________________________________________________________ -->
				2830	<div class="doc_subsubsection">
				2831	<a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
				2832	</div>
				2833
				2834	<div class="doc_text">
				2835
				2836	<h5>Syntax:</h5>
				2837
				2838	<pre>
Dan Gohman	bcc3c50	2008-05-12 23:38:42 +0000	[diff] [blame]	2839	<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]	2840	</pre>
				2841
				2842	<h5>Overview:</h5>
				2843
				2844	<p>
				2845	The '<tt>insertelement</tt>' instruction inserts a scalar
				2846	element into a vector at a specified index.
				2847	</p>
				2848
				2849
				2850	<h5>Arguments:</h5>
				2851
				2852	<p>
				2853	The first operand of an '<tt>insertelement</tt>' instruction is a
				2854	value of <a href="#t_vector">vector</a> type. The second operand is a
				2855	scalar value whose type must equal the element type of the first
				2856	operand. The third operand is an index indicating the position at
				2857	which to insert the value. The index may be a variable.</p>
				2858
				2859	<h5>Semantics:</h5>
				2860
				2861	<p>
				2862	The result is a vector of the same type as <tt>val</tt>. Its
				2863	element values are those of <tt>val</tt> except at position
				2864	<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
				2865	exceeds the length of <tt>val</tt>, the results are undefined.
				2866	</p>
				2867
				2868	<h5>Example:</h5>
				2869
				2870	<pre>
				2871	%result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
				2872	</pre>
				2873	</div>
				2874
				2875	<!-- _______________________________________________________________________ -->
				2876	<div class="doc_subsubsection">
				2877	<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
				2878	</div>
				2879
				2880	<div class="doc_text">
				2881
				2882	<h5>Syntax:</h5>
				2883
				2884	<pre>
				2885	<result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x i32> <mask> <i>; yields <n x <ty>></i>
				2886	</pre>
				2887
				2888	<h5>Overview:</h5>
				2889
				2890	<p>
				2891	The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
				2892	from two input vectors, returning a vector of the same type.
				2893	</p>
				2894
				2895	<h5>Arguments:</h5>
				2896
				2897	<p>
				2898	The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
				2899	with types that match each other and types that match the result of the
				2900	instruction. The third argument is a shuffle mask, which has the same number
				2901	of elements as the other vector type, but whose element type is always 'i32'.
				2902	</p>
				2903
				2904	<p>
				2905	The shuffle mask operand is required to be a constant vector with either
				2906	constant integer or undef values.
				2907	</p>
				2908
				2909	<h5>Semantics:</h5>
				2910
				2911	<p>
				2912	The elements of the two input vectors are numbered from left to right across
				2913	both of the vectors. The shuffle mask operand specifies, for each element of
				2914	the result vector, which element of the two input registers the result element
				2915	gets. The element selector may be undef (meaning "don't care") and the second
				2916	operand may be undef if performing a shuffle from only one vector.
				2917	</p>
				2918
				2919	<h5>Example:</h5>
				2920
				2921	<pre>
				2922	%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
				2923	<4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
				2924	%result = shufflevector <4 x i32> %v1, <4 x i32> undef,
				2925	<4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
				2926	</pre>
				2927	</div>
				2928
				2929
				2930	<!-- ======================================================================= -->
				2931	<div class="doc_subsection">
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2932	<a name="aggregateops">Aggregate Operations</a>
				2933	</div>
				2934
				2935	<div class="doc_text">
				2936
				2937	<p>LLVM supports several instructions for working with aggregate values.
				2938	</p>
				2939
				2940	</div>
				2941
				2942	<!-- _______________________________________________________________________ -->
				2943	<div class="doc_subsubsection">
				2944	<a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
				2945	</div>
				2946
				2947	<div class="doc_text">
				2948
				2949	<h5>Syntax:</h5>
				2950
				2951	<pre>
				2952	<result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
				2953	</pre>
				2954
				2955	<h5>Overview:</h5>
				2956
				2957	<p>
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	2958	The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
				2959	or array element from an aggregate value.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2960	</p>
				2961
				2962
				2963	<h5>Arguments:</h5>
				2964
				2965	<p>
				2966	The first operand of an '<tt>extractvalue</tt>' instruction is a
				2967	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]	2968	type. The operands are constant indices to specify which value to extract
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2969	in a similar manner as indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2970	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				2971	</p>
				2972
				2973	<h5>Semantics:</h5>
				2974
				2975	<p>
				2976	The result is the value at the position in the aggregate specified by
				2977	the index operands.
				2978	</p>
				2979
				2980	<h5>Example:</h5>
				2981
				2982	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2983	%result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2984	</pre>
				2985	</div>
				2986
				2987
				2988	<!-- _______________________________________________________________________ -->
				2989	<div class="doc_subsubsection">
				2990	<a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
				2991	</div>
				2992
				2993	<div class="doc_text">
				2994
				2995	<h5>Syntax:</h5>
				2996
				2997	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2998	<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]	2999	</pre>
				3000
				3001	<h5>Overview:</h5>
				3002
				3003	<p>
				3004	The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3005	into a struct field or array element in an aggregate.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3006	</p>
				3007
				3008
				3009	<h5>Arguments:</h5>
				3010
				3011	<p>
				3012	The first operand of an '<tt>insertvalue</tt>' instruction is a
				3013	value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
				3014	The second operand is a first-class value to insert.
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	3015	The following operands are constant indices
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3016	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]	3017	indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3018	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				3019	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]	3020	by the indices.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3021
				3022	<h5>Semantics:</h5>
				3023
				3024	<p>
				3025	The result is an aggregate of the same type as <tt>val</tt>. Its
				3026	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]	3027	specified by the indices is that of <tt>elt</tt>.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3028	</p>
				3029
				3030	<h5>Example:</h5>
				3031
				3032	<pre>
Dan Gohman	b1aab4e	2008-06-23 15:26:37 +0000	[diff] [blame]	3033	%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]	3034	</pre>
				3035	</div>
				3036
				3037
				3038	<!-- ======================================================================= -->
				3039	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3040	<a name="memoryops">Memory Access and Addressing Operations</a>
				3041	</div>
				3042
				3043	<div class="doc_text">
				3044
				3045	<p>A key design point of an SSA-based representation is how it
				3046	represents memory. In LLVM, no memory locations are in SSA form, which
				3047	makes things very simple. This section describes how to read, write,
				3048	allocate, and free memory in LLVM.</p>
				3049
				3050	</div>
				3051
				3052	<!-- _______________________________________________________________________ -->
				3053	<div class="doc_subsubsection">
				3054	<a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
				3055	</div>
				3056
				3057	<div class="doc_text">
				3058
				3059	<h5>Syntax:</h5>
				3060
				3061	<pre>
				3062	<result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3063	</pre>
				3064
				3065	<h5>Overview:</h5>
				3066
				3067	<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3068	heap and returns a pointer to it. The object is always allocated in the generic
				3069	address space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3070
				3071	<h5>Arguments:</h5>
				3072
				3073	<p>The '<tt>malloc</tt>' instruction allocates
				3074	<tt>sizeof(<type>)*NumElements</tt>
				3075	bytes of memory from the operating system and returns a pointer of the
				3076	appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3077	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3078	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]	3079	be aligned to at least that boundary. If not specified, or if zero, the target can
				3080	choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3081
				3082	<p>'<tt>type</tt>' must be a sized type.</p>
				3083
				3084	<h5>Semantics:</h5>
				3085
				3086	<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3087	a pointer is returned. The result of a zero byte allocattion is undefined. The
				3088	result is null if there is insufficient memory available.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3089
				3090	<h5>Example:</h5>
				3091
				3092	<pre>
				3093	%array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
				3094
				3095	%size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
				3096	%array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
				3097	%array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
				3098	%array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
				3099	%array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
				3100	</pre>
				3101	</div>
				3102
				3103	<!-- _______________________________________________________________________ -->
				3104	<div class="doc_subsubsection">
				3105	<a name="i_free">'<tt>free</tt>' Instruction</a>
				3106	</div>
				3107
				3108	<div class="doc_text">
				3109
				3110	<h5>Syntax:</h5>
				3111
				3112	<pre>
				3113	free <type> <value> <i>; yields {void}</i>
				3114	</pre>
				3115
				3116	<h5>Overview:</h5>
				3117
				3118	<p>The '<tt>free</tt>' instruction returns memory back to the unused
				3119	memory heap to be reallocated in the future.</p>
				3120
				3121	<h5>Arguments:</h5>
				3122
				3123	<p>'<tt>value</tt>' shall be a pointer value that points to a value
				3124	that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
				3125	instruction.</p>
				3126
				3127	<h5>Semantics:</h5>
				3128
				3129	<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]	3130	after this instruction executes. If the pointer is null, the operation
				3131	is a noop.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3132
				3133	<h5>Example:</h5>
				3134
				3135	<pre>
				3136	%array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
				3137	free [4 x i8]* %array
				3138	</pre>
				3139	</div>
				3140
				3141	<!-- _______________________________________________________________________ -->
				3142	<div class="doc_subsubsection">
				3143	<a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
				3144	</div>
				3145
				3146	<div class="doc_text">
				3147
				3148	<h5>Syntax:</h5>
				3149
				3150	<pre>
				3151	<result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3152	</pre>
				3153
				3154	<h5>Overview:</h5>
				3155
				3156	<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
				3157	currently executing function, to be automatically released when this function
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3158	returns to its caller. The object is always allocated in the generic address
				3159	space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3160
				3161	<h5>Arguments:</h5>
				3162
				3163	<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
				3164	bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3165	appropriate type to the program. If "NumElements" is specified, it is the
				3166	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3167	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]	3168	to be aligned to at least that boundary. If not specified, or if zero, the target
				3169	can choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3170
				3171	<p>'<tt>type</tt>' may be any sized type.</p>
				3172
				3173	<h5>Semantics:</h5>
				3174
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3175	<p>Memory is allocated; a pointer is returned. The operation is undefiend if
				3176	there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3177	memory is automatically released when the function returns. The '<tt>alloca</tt>'
				3178	instruction is commonly used to represent automatic variables that must
				3179	have an address available. When the function returns (either with the <tt><a
				3180	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]	3181	instructions), the memory is reclaimed. Allocating zero bytes
				3182	is legal, but the result is undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3183
				3184	<h5>Example:</h5>
				3185
				3186	<pre>
				3187	%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
				3188	%ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
				3189	%ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
				3190	%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
				3191	</pre>
				3192	</div>
				3193
				3194	<!-- _______________________________________________________________________ -->
				3195	<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
				3196	Instruction</a> </div>
				3197	<div class="doc_text">
				3198	<h5>Syntax:</h5>
				3199	<pre> <result> = load <ty>* <pointer>[, align <alignment>]<br> <result> = volatile load <ty>* <pointer>[, align <alignment>]<br></pre>
				3200	<h5>Overview:</h5>
				3201	<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
				3202	<h5>Arguments:</h5>
				3203	<p>The argument to the '<tt>load</tt>' instruction specifies the memory
				3204	address from which to load. The pointer must point to a <a
				3205	href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
				3206	marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
				3207	the number or order of execution of this <tt>load</tt> with other
				3208	volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
				3209	instructions. </p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3210	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3211	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3212	(that is, the alignment of the memory address). A value of 0 or an
				3213	omitted "align" argument means that the operation has the preferential
				3214	alignment for the target. It is the responsibility of the code emitter
				3215	to ensure that the alignment information is correct. Overestimating
				3216	the alignment results in an undefined behavior. Underestimating the
				3217	alignment may produce less efficient code. An alignment of 1 is always
				3218	safe.
				3219	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3220	<h5>Semantics:</h5>
				3221	<p>The location of memory pointed to is loaded.</p>
				3222	<h5>Examples:</h5>
				3223	<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
				3224	<a
				3225	href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
				3226	%val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
				3227	</pre>
				3228	</div>
				3229	<!-- _______________________________________________________________________ -->
				3230	<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
				3231	Instruction</a> </div>
				3232	<div class="doc_text">
				3233	<h5>Syntax:</h5>
				3234	<pre> store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3235	volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3236	</pre>
				3237	<h5>Overview:</h5>
				3238	<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
				3239	<h5>Arguments:</h5>
				3240	<p>There are two arguments to the '<tt>store</tt>' instruction: a value
				3241	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]	3242	operand must be a pointer to the <a href="#t_firstclass">first class</a> type
				3243	of the '<tt><value></tt>'
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3244	operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
				3245	optimizer is not allowed to modify the number or order of execution of
				3246	this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
				3247	href="#i_store">store</a></tt> instructions.</p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3248	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3249	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3250	(that is, the alignment of the memory address). A value of 0 or an
				3251	omitted "align" argument means that the operation has the preferential
				3252	alignment for the target. It is the responsibility of the code emitter
				3253	to ensure that the alignment information is correct. Overestimating
				3254	the alignment results in an undefined behavior. Underestimating the
				3255	alignment may produce less efficient code. An alignment of 1 is always
				3256	safe.
				3257	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3258	<h5>Semantics:</h5>
				3259	<p>The contents of memory are updated to contain '<tt><value></tt>'
				3260	at the location specified by the '<tt><pointer></tt>' operand.</p>
				3261	<h5>Example:</h5>
				3262	<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]	3263	store i32 3, i32* %ptr <i>; yields {void}</i>
				3264	%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]	3265	</pre>
				3266	</div>
				3267
				3268	<!-- _______________________________________________________________________ -->
				3269	<div class="doc_subsubsection">
				3270	<a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
				3271	</div>
				3272
				3273	<div class="doc_text">
				3274	<h5>Syntax:</h5>
				3275	<pre>
				3276	<result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}*
				3277	</pre>
				3278
				3279	<h5>Overview:</h5>
				3280
				3281	<p>
				3282	The '<tt>getelementptr</tt>' instruction is used to get the address of a
				3283	subelement of an aggregate data structure.</p>
				3284
				3285	<h5>Arguments:</h5>
				3286
				3287	<p>This instruction takes a list of integer operands that indicate what
				3288	elements of the aggregate object to index to. The actual types of the arguments
				3289	provided depend on the type of the first pointer argument. The
				3290	'<tt>getelementptr</tt>' instruction is used to index down through the type
				3291	levels of a structure or to a specific index in an array. When indexing into a
				3292	structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	3293	into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
				3294	values will be sign extended to 64-bits if required.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3295
				3296	<p>For example, let's consider a C code fragment and how it gets
				3297	compiled to LLVM:</p>
				3298
				3299	<div class="doc_code">
				3300	<pre>
				3301	struct RT {
				3302	char A;
				3303	int B[10][20];
				3304	char C;
				3305	};
				3306	struct ST {
				3307	int X;
				3308	double Y;
				3309	struct RT Z;
				3310	};
				3311
				3312	int foo(struct ST s) {
				3313	return &s[1].Z.B[5][13];
				3314	}
				3315	</pre>
				3316	</div>
				3317
				3318	<p>The LLVM code generated by the GCC frontend is:</p>
				3319
				3320	<div class="doc_code">
				3321	<pre>
				3322	%RT = type { i8 , [10 x [20 x i32]], i8 }
				3323	%ST = type { i32, double, %RT }
				3324
				3325	define i32* %foo(%ST* %s) {
				3326	entry:
				3327	%reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
				3328	ret i32* %reg
				3329	}
				3330	</pre>
				3331	</div>
				3332
				3333	<h5>Semantics:</h5>
				3334
				3335	<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
				3336	on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
				3337	and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
				3338	<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]	3339	to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
				3340	structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3341
				3342	<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
				3343	type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
				3344	}</tt>' type, a structure. The second index indexes into the third element of
				3345	the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
				3346	i8 }</tt>' type, another structure. The third index indexes into the second
				3347	element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
				3348	array. The two dimensions of the array are subscripted into, yielding an
				3349	'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
				3350	to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
				3351
				3352	<p>Note that it is perfectly legal to index partially through a
				3353	structure, returning a pointer to an inner element. Because of this,
				3354	the LLVM code for the given testcase is equivalent to:</p>
				3355
				3356	<pre>
				3357	define i32* %foo(%ST* %s) {
				3358	%t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
				3359	%t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
				3360	%t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
				3361	%t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
				3362	%t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
				3363	ret i32* %t5
				3364	}
				3365	</pre>
				3366
				3367	<p>Note that it is undefined to access an array out of bounds: array and
				3368	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]	3369	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]	3370	defined to be accessible as variable length arrays, which requires access
				3371	beyond the zero'th element.</p>
				3372
				3373	<p>The getelementptr instruction is often confusing. For some more insight
				3374	into how it works, see <a href="GetElementPtr.html">the getelementptr
				3375	FAQ</a>.</p>
				3376
				3377	<h5>Example:</h5>
				3378
				3379	<pre>
				3380	<i>; yields [12 x i8]*:aptr</i>
				3381	%aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
				3382	</pre>
				3383	</div>
				3384
				3385	<!-- ======================================================================= -->
				3386	<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
				3387	</div>
				3388	<div class="doc_text">
				3389	<p>The instructions in this category are the conversion instructions (casting)
				3390	which all take a single operand and a type. They perform various bit conversions
				3391	on the operand.</p>
				3392	</div>
				3393
				3394	<!-- _______________________________________________________________________ -->
				3395	<div class="doc_subsubsection">
				3396	<a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
				3397	</div>
				3398	<div class="doc_text">
				3399
				3400	<h5>Syntax:</h5>
				3401	<pre>
				3402	<result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3403	</pre>
				3404
				3405	<h5>Overview:</h5>
				3406	<p>
				3407	The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
				3408	</p>
				3409
				3410	<h5>Arguments:</h5>
				3411	<p>
				3412	The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
				3413	be an <a href="#t_integer">integer</a> type, and a type that specifies the size
				3414	and type of the result, which must be an <a href="#t_integer">integer</a>
				3415	type. The bit size of <tt>value</tt> must be larger than the bit size of
				3416	<tt>ty2</tt>. Equal sized types are not allowed.</p>
				3417
				3418	<h5>Semantics:</h5>
				3419	<p>
				3420	The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
				3421	and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
				3422	larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
				3423	It will always truncate bits.</p>
				3424
				3425	<h5>Example:</h5>
				3426	<pre>
				3427	%X = trunc i32 257 to i8 <i>; yields i8:1</i>
				3428	%Y = trunc i32 123 to i1 <i>; yields i1:true</i>
				3429	%Y = trunc i32 122 to i1 <i>; yields i1:false</i>
				3430	</pre>
				3431	</div>
				3432
				3433	<!-- _______________________________________________________________________ -->
				3434	<div class="doc_subsubsection">
				3435	<a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
				3436	</div>
				3437	<div class="doc_text">
				3438
				3439	<h5>Syntax:</h5>
				3440	<pre>
				3441	<result> = zext <ty> <value> to <ty2> <i>; yields ty2</i>
				3442	</pre>
				3443
				3444	<h5>Overview:</h5>
				3445	<p>The '<tt>zext</tt>' instruction zero extends its operand to type
				3446	<tt>ty2</tt>.</p>
				3447
				3448
				3449	<h5>Arguments:</h5>
				3450	<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
				3451	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3452	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3453	<tt>value</tt> must be smaller than the bit size of the destination type,
				3454	<tt>ty2</tt>.</p>
				3455
				3456	<h5>Semantics:</h5>
				3457	<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
				3458	bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
				3459
				3460	<p>When zero extending from i1, the result will always be either 0 or 1.</p>
				3461
				3462	<h5>Example:</h5>
				3463	<pre>
				3464	%X = zext i32 257 to i64 <i>; yields i64:257</i>
				3465	%Y = zext i1 true to i32 <i>; yields i32:1</i>
				3466	</pre>
				3467	</div>
				3468
				3469	<!-- _______________________________________________________________________ -->
				3470	<div class="doc_subsubsection">
				3471	<a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
				3472	</div>
				3473	<div class="doc_text">
				3474
				3475	<h5>Syntax:</h5>
				3476	<pre>
				3477	<result> = sext <ty> <value> to <ty2> <i>; yields ty2</i>
				3478	</pre>
				3479
				3480	<h5>Overview:</h5>
				3481	<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
				3482
				3483	<h5>Arguments:</h5>
				3484	<p>
				3485	The '<tt>sext</tt>' instruction takes a value to cast, which must be of
				3486	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3487	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3488	<tt>value</tt> must be smaller than the bit size of the destination type,
				3489	<tt>ty2</tt>.</p>
				3490
				3491	<h5>Semantics:</h5>
				3492	<p>
				3493	The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
				3494	bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
				3495	the type <tt>ty2</tt>.</p>
				3496
				3497	<p>When sign extending from i1, the extension always results in -1 or 0.</p>
				3498
				3499	<h5>Example:</h5>
				3500	<pre>
				3501	%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
				3502	%Y = sext i1 true to i32 <i>; yields i32:-1</i>
				3503	</pre>
				3504	</div>
				3505
				3506	<!-- _______________________________________________________________________ -->
				3507	<div class="doc_subsubsection">
				3508	<a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
				3509	</div>
				3510
				3511	<div class="doc_text">
				3512
				3513	<h5>Syntax:</h5>
				3514
				3515	<pre>
				3516	<result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3517	</pre>
				3518
				3519	<h5>Overview:</h5>
				3520	<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
				3521	<tt>ty2</tt>.</p>
				3522
				3523
				3524	<h5>Arguments:</h5>
				3525	<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
				3526	point</a> value to cast and a <a href="#t_floating">floating point</a> type to
				3527	cast it to. The size of <tt>value</tt> must be larger than the size of
				3528	<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
				3529	<i>no-op cast</i>.</p>
				3530
				3531	<h5>Semantics:</h5>
				3532	<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
				3533	<a href="#t_floating">floating point</a> type to a smaller
				3534	<a href="#t_floating">floating point</a> type. If the value cannot fit within
				3535	the destination type, <tt>ty2</tt>, then the results are undefined.</p>
				3536
				3537	<h5>Example:</h5>
				3538	<pre>
				3539	%X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
				3540	%Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
				3541	</pre>
				3542	</div>
				3543
				3544	<!-- _______________________________________________________________________ -->
				3545	<div class="doc_subsubsection">
				3546	<a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
				3547	</div>
				3548	<div class="doc_text">
				3549
				3550	<h5>Syntax:</h5>
				3551	<pre>
				3552	<result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i>
				3553	</pre>
				3554
				3555	<h5>Overview:</h5>
				3556	<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
				3557	floating point value.</p>
				3558
				3559	<h5>Arguments:</h5>
				3560	<p>The '<tt>fpext</tt>' instruction takes a
				3561	<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
				3562	and a <a href="#t_floating">floating point</a> type to cast it to. The source
				3563	type must be smaller than the destination type.</p>
				3564
				3565	<h5>Semantics:</h5>
				3566	<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
				3567	<a href="#t_floating">floating point</a> type to a larger
				3568	<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
				3569	used to make a <i>no-op cast</i> because it always changes bits. Use
				3570	<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
				3571
				3572	<h5>Example:</h5>
				3573	<pre>
				3574	%X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
				3575	%Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
				3576	</pre>
				3577	</div>
				3578
				3579	<!-- _______________________________________________________________________ -->
				3580	<div class="doc_subsubsection">
				3581	<a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
				3582	</div>
				3583	<div class="doc_text">
				3584
				3585	<h5>Syntax:</h5>
				3586	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3587	<result> = fptoui <ty> <value> to <ty2> <i>; yields ty2</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3588	</pre>
				3589
				3590	<h5>Overview:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3591	<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]	3592	unsigned integer equivalent of type <tt>ty2</tt>.
				3593	</p>
				3594
				3595	<h5>Arguments:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3596	<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]	3597	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3598	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3599	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3600	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]	3601
				3602	<h5>Semantics:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3603	<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3604	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3605	towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
				3606	the results are undefined.</p>
				3607
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3608	<h5>Example:</h5>
				3609	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3610	%X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3611	%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]	3612	%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]	3613	</pre>
				3614	</div>
				3615
				3616	<!-- _______________________________________________________________________ -->
				3617	<div class="doc_subsubsection">
				3618	<a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
				3619	</div>
				3620	<div class="doc_text">
				3621
				3622	<h5>Syntax:</h5>
				3623	<pre>
				3624	<result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i>
				3625	</pre>
				3626
				3627	<h5>Overview:</h5>
				3628	<p>The '<tt>fptosi</tt>' instruction converts
				3629	<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
				3630	</p>
				3631
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3632	<h5>Arguments:</h5>
				3633	<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]	3634	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3635	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3636	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3637	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]	3638
				3639	<h5>Semantics:</h5>
				3640	<p>The '<tt>fptosi</tt>' instruction converts its
				3641	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3642	towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
				3643	the results are undefined.</p>
				3644
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3645	<h5>Example:</h5>
				3646	<pre>
				3647	%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3648	%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]	3649	%X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
				3650	</pre>
				3651	</div>
				3652
				3653	<!-- _______________________________________________________________________ -->
				3654	<div class="doc_subsubsection">
				3655	<a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
				3656	</div>
				3657	<div class="doc_text">
				3658
				3659	<h5>Syntax:</h5>
				3660	<pre>
				3661	<result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3662	</pre>
				3663
				3664	<h5>Overview:</h5>
				3665	<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
				3666	integer and converts that value to the <tt>ty2</tt> type.</p>
				3667
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3668	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3669	<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
				3670	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3671	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3672	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3673	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]	3674
				3675	<h5>Semantics:</h5>
				3676	<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
				3677	integer quantity and converts it to the corresponding floating point value. If
				3678	the value cannot fit in the floating point value, the results are undefined.</p>
				3679
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3680	<h5>Example:</h5>
				3681	<pre>
				3682	%X = uitofp i32 257 to float <i>; yields float:257.0</i>
				3683	%Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
				3684	</pre>
				3685	</div>
				3686
				3687	<!-- _______________________________________________________________________ -->
				3688	<div class="doc_subsubsection">
				3689	<a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
				3690	</div>
				3691	<div class="doc_text">
				3692
				3693	<h5>Syntax:</h5>
				3694	<pre>
				3695	<result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3696	</pre>
				3697
				3698	<h5>Overview:</h5>
				3699	<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
				3700	integer and converts that value to the <tt>ty2</tt> type.</p>
				3701
				3702	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3703	<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
				3704	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3705	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3706	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3707	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]	3708
				3709	<h5>Semantics:</h5>
				3710	<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
				3711	integer quantity and converts it to the corresponding floating point value. If
				3712	the value cannot fit in the floating point value, the results are undefined.</p>
				3713
				3714	<h5>Example:</h5>
				3715	<pre>
				3716	%X = sitofp i32 257 to float <i>; yields float:257.0</i>
				3717	%Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
				3718	</pre>
				3719	</div>
				3720
				3721	<!-- _______________________________________________________________________ -->
				3722	<div class="doc_subsubsection">
				3723	<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
				3724	</div>
				3725	<div class="doc_text">
				3726
				3727	<h5>Syntax:</h5>
				3728	<pre>
				3729	<result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i>
				3730	</pre>
				3731
				3732	<h5>Overview:</h5>
				3733	<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
				3734	the integer type <tt>ty2</tt>.</p>
				3735
				3736	<h5>Arguments:</h5>
				3737	<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
				3738	must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
				3739	<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
				3740
				3741	<h5>Semantics:</h5>
				3742	<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
				3743	<tt>ty2</tt> by interpreting the pointer value as an integer and either
				3744	truncating or zero extending that value to the size of the integer type. If
				3745	<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
				3746	<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
				3747	are the same size, then nothing is done (<i>no-op cast</i>) other than a type
				3748	change.</p>
				3749
				3750	<h5>Example:</h5>
				3751	<pre>
				3752	%X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
				3753	%Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
				3754	</pre>
				3755	</div>
				3756
				3757	<!-- _______________________________________________________________________ -->
				3758	<div class="doc_subsubsection">
				3759	<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
				3760	</div>
				3761	<div class="doc_text">
				3762
				3763	<h5>Syntax:</h5>
				3764	<pre>
				3765	<result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i>
				3766	</pre>
				3767
				3768	<h5>Overview:</h5>
				3769	<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
				3770	a pointer type, <tt>ty2</tt>.</p>
				3771
				3772	<h5>Arguments:</h5>
				3773	<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
				3774	value to cast, and a type to cast it to, which must be a
				3775	<a href="#t_pointer">pointer</a> type.
				3776
				3777	<h5>Semantics:</h5>
				3778	<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
				3779	<tt>ty2</tt> by applying either a zero extension or a truncation depending on
				3780	the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
				3781	size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
				3782	the size of a pointer then a zero extension is done. If they are the same size,
				3783	nothing is done (<i>no-op cast</i>).</p>
				3784
				3785	<h5>Example:</h5>
				3786	<pre>
				3787	%X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
				3788	%X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
				3789	%Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
				3790	</pre>
				3791	</div>
				3792
				3793	<!-- _______________________________________________________________________ -->
				3794	<div class="doc_subsubsection">
				3795	<a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
				3796	</div>
				3797	<div class="doc_text">
				3798
				3799	<h5>Syntax:</h5>
				3800	<pre>
				3801	<result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i>
				3802	</pre>
				3803
				3804	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3805
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3806	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3807	<tt>ty2</tt> without changing any bits.</p>
				3808
				3809	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3810
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3811	<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman	7305fa0	2008-09-08 16:45:59 +0000	[diff] [blame]	3812	a non-aggregate first class value, and a type to cast it to, which must also be
				3813	a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
				3814	<tt>value</tt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3815	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]	3816	type is a pointer, the destination type must also be a pointer. This
				3817	instruction supports bitwise conversion of vectors to integers and to vectors
				3818	of other types (as long as they have the same size).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3819
				3820	<h5>Semantics:</h5>
				3821	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3822	<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
				3823	this conversion. The conversion is done as if the <tt>value</tt> had been
				3824	stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
				3825	converted to other pointer types with this instruction. To convert pointers to
				3826	other types, use the <a href="#i_inttoptr">inttoptr</a> or
				3827	<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
				3828
				3829	<h5>Example:</h5>
				3830	<pre>
				3831	%X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
				3832	%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
				3833	%Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
				3834	</pre>
				3835	</div>
				3836
				3837	<!-- ======================================================================= -->
				3838	<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
				3839	<div class="doc_text">
				3840	<p>The instructions in this category are the "miscellaneous"
				3841	instructions, which defy better classification.</p>
				3842	</div>
				3843
				3844	<!-- _______________________________________________________________________ -->
				3845	<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
				3846	</div>
				3847	<div class="doc_text">
				3848	<h5>Syntax:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3849	<pre> <result> = icmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1&gt}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3850	</pre>
				3851	<h5>Overview:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3852	<p>The '<tt>icmp</tt>' instruction returns a boolean value or
				3853	a vector of boolean values based on comparison
				3854	of its two integer, integer vector, or pointer operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3855	<h5>Arguments:</h5>
				3856	<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
				3857	the condition code indicating the kind of comparison to perform. It is not
				3858	a value, just a keyword. The possible condition code are:
				3859	<ol>
				3860	<li><tt>eq</tt>: equal</li>
				3861	<li><tt>ne</tt>: not equal </li>
				3862	<li><tt>ugt</tt>: unsigned greater than</li>
				3863	<li><tt>uge</tt>: unsigned greater or equal</li>
				3864	<li><tt>ult</tt>: unsigned less than</li>
				3865	<li><tt>ule</tt>: unsigned less or equal</li>
				3866	<li><tt>sgt</tt>: signed greater than</li>
				3867	<li><tt>sge</tt>: signed greater or equal</li>
				3868	<li><tt>slt</tt>: signed less than</li>
				3869	<li><tt>sle</tt>: signed less or equal</li>
				3870	</ol>
				3871	<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3872	<a href="#t_pointer">pointer</a>
				3873	or integer <a href="#t_vector">vector</a> typed.
				3874	They must also be identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3875	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3876	<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]	3877	the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3878	yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3879	<ol>
				3880	<li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
				3881	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3882	</li>
				3883	<li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
				3884	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3885	<li><tt>ugt</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 greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3887	<li><tt>uge</tt>: interprets the operands as unsigned 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 or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3889	<li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3890	<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]	3891	<li><tt>ule</tt>: interprets the operands as unsigned 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 or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3893	<li><tt>sgt</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 greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3895	<li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3896	<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]	3897	<li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3898	<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]	3899	<li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3900	<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]	3901	</ol>
				3902	<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
				3903	values are compared as if they were integers.</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3904	<p>If the operands are integer vectors, then they are compared
				3905	element by element. The result is an <tt>i1</tt> vector with
				3906	the same number of elements as the values being compared.
				3907	Otherwise, the result is an <tt>i1</tt>.
				3908	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3909
				3910	<h5>Example:</h5>
				3911	<pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
				3912	<result> = icmp ne float* %X, %X <i>; yields: result=false</i>
				3913	<result> = icmp ult i16 4, 5 <i>; yields: result=true</i>
				3914	<result> = icmp sgt i16 4, 5 <i>; yields: result=false</i>
				3915	<result> = icmp ule i16 -4, 5 <i>; yields: result=false</i>
				3916	<result> = icmp sge i16 4, 5 <i>; yields: result=false</i>
				3917	</pre>
				3918	</div>
				3919
				3920	<!-- _______________________________________________________________________ -->
				3921	<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
				3922	</div>
				3923	<div class="doc_text">
				3924	<h5>Syntax:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3925	<pre> <result> = fcmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1&gt}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3926	</pre>
				3927	<h5>Overview:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3928	<p>The '<tt>fcmp</tt>' instruction returns a boolean value
				3929	or vector of boolean values based on comparison
				3930	of its operands.
				3931	<p>
				3932	If the operands are floating point scalars, then the result
				3933	type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
				3934	</p>
				3935	<p>If the operands are floating point vectors, then the result type
				3936	is a vector of boolean with the same number of elements as the
				3937	operands being compared.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3938	<h5>Arguments:</h5>
				3939	<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
				3940	the condition code indicating the kind of comparison to perform. It is not
				3941	a value, just a keyword. The possible condition code are:
				3942	<ol>
				3943	<li><tt>false</tt>: no comparison, always returns false</li>
				3944	<li><tt>oeq</tt>: ordered and equal</li>
				3945	<li><tt>ogt</tt>: ordered and greater than </li>
				3946	<li><tt>oge</tt>: ordered and greater than or equal</li>
				3947	<li><tt>olt</tt>: ordered and less than </li>
				3948	<li><tt>ole</tt>: ordered and less than or equal</li>
				3949	<li><tt>one</tt>: ordered and not equal</li>
				3950	<li><tt>ord</tt>: ordered (no nans)</li>
				3951	<li><tt>ueq</tt>: unordered or equal</li>
				3952	<li><tt>ugt</tt>: unordered or greater than </li>
				3953	<li><tt>uge</tt>: unordered or greater than or equal</li>
				3954	<li><tt>ult</tt>: unordered or less than </li>
				3955	<li><tt>ule</tt>: unordered or less than or equal</li>
				3956	<li><tt>une</tt>: unordered or not equal</li>
				3957	<li><tt>uno</tt>: unordered (either nans)</li>
				3958	<li><tt>true</tt>: no comparison, always returns true</li>
				3959	</ol>
				3960	<p><i>Ordered</i> means that neither operand is a QNAN while
				3961	<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3962	<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
				3963	either a <a href="#t_floating">floating point</a> type
				3964	or a <a href="#t_vector">vector</a> of floating point type.
				3965	They must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3966	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3967	<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3968	according to the condition code given as <tt>cond</tt>.
				3969	If the operands are vectors, then the vectors are compared
				3970	element by element.
				3971	Each comparison performed
				3972	always yields an <a href="#t_primitive">i1</a> result, as follows:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3973	<ol>
				3974	<li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
				3975	<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]	3976	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3977	<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]	3978	<tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3979	<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]	3980	<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]	3981	<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]	3982	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3983	<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]	3984	<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]	3985	<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]	3986	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3987	<li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
				3988	<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]	3989	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3990	<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]	3991	<tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3992	<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]	3993	<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]	3994	<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]	3995	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3996	<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]	3997	<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]	3998	<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]	3999	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4000	<li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
				4001	<li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
				4002	</ol>
				4003
				4004	<h5>Example:</h5>
				4005	<pre> <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4006	<result> = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
				4007	<result> = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
				4008	<result> = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4009	</pre>
				4010	</div>
				4011
				4012	<!-- _______________________________________________________________________ -->
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4013	<div class="doc_subsubsection">
				4014	<a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
				4015	</div>
				4016	<div class="doc_text">
				4017	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4018	<pre> <result> = vicmp <cond> <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4019	</pre>
				4020	<h5>Overview:</h5>
				4021	<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
				4022	element-wise comparison of its two integer vector operands.</p>
				4023	<h5>Arguments:</h5>
				4024	<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
				4025	the condition code indicating the kind of comparison to perform. It is not
				4026	a value, just a keyword. The possible condition code are:
				4027	<ol>
				4028	<li><tt>eq</tt>: equal</li>
				4029	<li><tt>ne</tt>: not equal </li>
				4030	<li><tt>ugt</tt>: unsigned greater than</li>
				4031	<li><tt>uge</tt>: unsigned greater or equal</li>
				4032	<li><tt>ult</tt>: unsigned less than</li>
				4033	<li><tt>ule</tt>: unsigned less or equal</li>
				4034	<li><tt>sgt</tt>: signed greater than</li>
				4035	<li><tt>sge</tt>: signed greater or equal</li>
				4036	<li><tt>slt</tt>: signed less than</li>
				4037	<li><tt>sle</tt>: signed less or equal</li>
				4038	</ol>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4039	<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4040	<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
				4041	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4042	<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]	4043	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4044	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
				4045	identical type as the values being compared. The most significant bit in each
				4046	element is 1 if the element-wise comparison evaluates to true, and is 0
				4047	otherwise. All other bits of the result are undefined. The condition codes
				4048	are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
				4049	instruction</a>.
				4050
				4051	<h5>Example:</h5>
				4052	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4053	<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>
				4054	<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]	4055	</pre>
				4056	</div>
				4057
				4058	<!-- _______________________________________________________________________ -->
				4059	<div class="doc_subsubsection">
				4060	<a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
				4061	</div>
				4062	<div class="doc_text">
				4063	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4064	<pre> <result> = vfcmp <cond> <ty> <op1>, <op2></pre>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4065	<h5>Overview:</h5>
				4066	<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
				4067	element-wise comparison of its two floating point vector operands. The output
				4068	elements have the same width as the input elements.</p>
				4069	<h5>Arguments:</h5>
				4070	<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
				4071	the condition code indicating the kind of comparison to perform. It is not
				4072	a value, just a keyword. The possible condition code are:
				4073	<ol>
				4074	<li><tt>false</tt>: no comparison, always returns false</li>
				4075	<li><tt>oeq</tt>: ordered and equal</li>
				4076	<li><tt>ogt</tt>: ordered and greater than </li>
				4077	<li><tt>oge</tt>: ordered and greater than or equal</li>
				4078	<li><tt>olt</tt>: ordered and less than </li>
				4079	<li><tt>ole</tt>: ordered and less than or equal</li>
				4080	<li><tt>one</tt>: ordered and not equal</li>
				4081	<li><tt>ord</tt>: ordered (no nans)</li>
				4082	<li><tt>ueq</tt>: unordered or equal</li>
				4083	<li><tt>ugt</tt>: unordered or greater than </li>
				4084	<li><tt>uge</tt>: unordered or greater than or equal</li>
				4085	<li><tt>ult</tt>: unordered or less than </li>
				4086	<li><tt>ule</tt>: unordered or less than or equal</li>
				4087	<li><tt>une</tt>: unordered or not equal</li>
				4088	<li><tt>uno</tt>: unordered (either nans)</li>
				4089	<li><tt>true</tt>: no comparison, always returns true</li>
				4090	</ol>
				4091	<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
				4092	<a href="#t_floating">floating point</a> typed. They must also be identical
				4093	types.</p>
				4094	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4095	<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]	4096	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4097	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
				4098	an identical number of elements as the values being compared, and each element
				4099	having identical with to the width of the floating point elements. The most
				4100	significant bit in each element is 1 if the element-wise comparison evaluates to
				4101	true, and is 0 otherwise. All other bits of the result are undefined. The
				4102	condition codes are evaluated identically to the
				4103	<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
				4104
				4105	<h5>Example:</h5>
				4106	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4107	<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>
				4108	<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]	4109	</pre>
				4110	</div>
				4111
				4112	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4113	<div class="doc_subsubsection">
				4114	<a name="i_phi">'<tt>phi</tt>' Instruction</a>
				4115	</div>
				4116
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4117	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4118
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4119	<h5>Syntax:</h5>
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	<pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre>
				4122	<h5>Overview:</h5>
				4123	<p>The '<tt>phi</tt>' instruction is used to implement the φ node in
				4124	the SSA graph representing the function.</p>
				4125	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4126
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4127	<p>The type of the incoming values is specified with the first type
				4128	field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
				4129	as arguments, with one pair for each predecessor basic block of the
				4130	current block. Only values of <a href="#t_firstclass">first class</a>
				4131	type may be used as the value arguments to the PHI node. Only labels
				4132	may be used as the label arguments.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4133
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4134	<p>There must be no non-phi instructions between the start of a basic
				4135	block and the PHI instructions: i.e. PHI instructions must be first in
				4136	a basic block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4137
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4138	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4139
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4140	<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
				4141	specified by the pair corresponding to the predecessor basic block that executed
				4142	just prior to the current block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4143
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4144	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4145	<pre>
				4146	Loop: ; Infinite loop that counts from 0 on up...
				4147	%indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
				4148	%nextindvar = add i32 %indvar, 1
				4149	br label %Loop
				4150	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4151	</div>
				4152
				4153	<!-- _______________________________________________________________________ -->
				4154	<div class="doc_subsubsection">
				4155	<a name="i_select">'<tt>select</tt>' Instruction</a>
				4156	</div>
				4157
				4158	<div class="doc_text">
				4159
				4160	<h5>Syntax:</h5>
				4161
				4162	<pre>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4163	<result> = select <i>selty</i> <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
				4164
				4165	<i>selty</i> is either i1 or {<N x i1&gt}
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4166	</pre>
				4167
				4168	<h5>Overview:</h5>
				4169
				4170	<p>
				4171	The '<tt>select</tt>' instruction is used to choose one value based on a
				4172	condition, without branching.
				4173	</p>
				4174
				4175
				4176	<h5>Arguments:</h5>
				4177
				4178	<p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4179	The '<tt>select</tt>' instruction requires an 'i1' value or
				4180	a vector of 'i1' values indicating the
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4181	condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4182	type. If the val1/val2 are vectors and
				4183	the condition is a scalar, then entire vectors are selected, not
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4184	individual elements.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4185	</p>
				4186
				4187	<h5>Semantics:</h5>
				4188
				4189	<p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4190	If the condition is an i1 and it evaluates to 1, the instruction returns the first
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4191	value argument; otherwise, it returns the second value argument.
				4192	</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4193	<p>
				4194	If the condition is a vector of i1, then the value arguments must
				4195	be vectors of the same size, and the selection is done element
				4196	by element.
				4197	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4198
				4199	<h5>Example:</h5>
				4200
				4201	<pre>
				4202	%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
				4203	</pre>
				4204	</div>
				4205
				4206
				4207	<!-- _______________________________________________________________________ -->
				4208	<div class="doc_subsubsection">
				4209	<a name="i_call">'<tt>call</tt>' Instruction</a>
				4210	</div>
				4211
				4212	<div class="doc_text">
				4213
				4214	<h5>Syntax:</h5>
				4215	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4216	<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]	4217	</pre>
				4218
				4219	<h5>Overview:</h5>
				4220
				4221	<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
				4222
				4223	<h5>Arguments:</h5>
				4224
				4225	<p>This instruction requires several arguments:</p>
				4226
				4227	<ol>
				4228	<li>
				4229	<p>The optional "tail" marker indicates whether the callee function accesses
				4230	any allocas or varargs in the caller. If the "tail" marker is present, the
				4231	function call is eligible for tail call optimization. Note that calls may
				4232	be marked "tail" even if they do not occur before a <a
				4233	href="#i_ret"><tt>ret</tt></a> instruction.
				4234	</li>
				4235	<li>
				4236	<p>The optional "cconv" marker indicates which <a href="#callingconv">calling
				4237	convention</a> the call should use. If none is specified, the call defaults
				4238	to using C calling conventions.
				4239	</li>
				4240	<li>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4241	<p>'<tt>ty</tt>': the type of the call instruction itself which is also
				4242	the type of the return value. Functions that return no value are marked
				4243	<tt><a href="#t_void">void</a></tt>.</p>
				4244	</li>
				4245	<li>
				4246	<p>'<tt>fnty</tt>': shall be the signature of the pointer to function
				4247	value being invoked. The argument types must match the types implied by
				4248	this signature. This type can be omitted if the function is not varargs
				4249	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]	4250	</li>
				4251	<li>
				4252	<p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
				4253	be invoked. In most cases, this is a direct function invocation, but
				4254	indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
				4255	to function value.</p>
				4256	</li>
				4257	<li>
				4258	<p>'<tt>function args</tt>': argument list whose types match the
				4259	function signature argument types. All arguments must be of
				4260	<a href="#t_firstclass">first class</a> type. If the function signature
				4261	indicates the function accepts a variable number of arguments, the extra
				4262	arguments can be specified.</p>
				4263	</li>
				4264	</ol>
				4265
				4266	<h5>Semantics:</h5>
				4267
				4268	<p>The '<tt>call</tt>' instruction is used to cause control flow to
				4269	transfer to a specified function, with its incoming arguments bound to
				4270	the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
				4271	instruction in the called function, control flow continues with the
				4272	instruction after the function call, and the return value of the
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4273	function is bound to the result argument. If the callee returns multiple
				4274	values then the return values of the function are only accessible through
				4275	the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4276
				4277	<h5>Example:</h5>
				4278
				4279	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4280	%retval = call i32 @test(i32 %argc)
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4281	call i32 (i8 , ...) @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
				4282	%X = tail call i32 @foo() <i>; yields i32</i>
				4283	%Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
				4284	call void %foo(i8 97 signext)
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4285
				4286	%struct.A = type { i32, i8 }
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4287	%r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
				4288	%gr = getresult %struct.A %r, 0 <i>; yields i32</i>
				4289	%gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4290	</pre>
				4291
				4292	</div>
				4293
				4294	<!-- _______________________________________________________________________ -->
				4295	<div class="doc_subsubsection">
				4296	<a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
				4297	</div>
				4298
				4299	<div class="doc_text">
				4300
				4301	<h5>Syntax:</h5>
				4302
				4303	<pre>
				4304	<resultval> = va_arg <va_list*> <arglist>, <argty>
				4305	</pre>
				4306
				4307	<h5>Overview:</h5>
				4308
				4309	<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
				4310	the "variable argument" area of a function call. It is used to implement the
				4311	<tt>va_arg</tt> macro in C.</p>
				4312
				4313	<h5>Arguments:</h5>
				4314
				4315	<p>This instruction takes a <tt>va_list*</tt> value and the type of
				4316	the argument. It returns a value of the specified argument type and
				4317	increments the <tt>va_list</tt> to point to the next argument. The
				4318	actual type of <tt>va_list</tt> is target specific.</p>
				4319
				4320	<h5>Semantics:</h5>
				4321
				4322	<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
				4323	type from the specified <tt>va_list</tt> and causes the
				4324	<tt>va_list</tt> to point to the next argument. For more information,
				4325	see the variable argument handling <a href="#int_varargs">Intrinsic
				4326	Functions</a>.</p>
				4327
				4328	<p>It is legal for this instruction to be called in a function which does not
				4329	take a variable number of arguments, for example, the <tt>vfprintf</tt>
				4330	function.</p>
				4331
				4332	<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
				4333	href="#intrinsics">intrinsic function</a> because it takes a type as an
				4334	argument.</p>
				4335
				4336	<h5>Example:</h5>
				4337
				4338	<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
				4339
				4340	</div>
				4341
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4342	<!-- _______________________________________________________________________ -->
				4343	<div class="doc_subsubsection">
				4344	<a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
				4345	</div>
				4346
				4347	<div class="doc_text">
				4348
				4349	<h5>Syntax:</h5>
				4350	<pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4351	<resultval> = getresult <type> <retval>, <index>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4352	</pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4353
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4354	<h5>Overview:</h5>
				4355
				4356	<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4357	from a '<tt><a href="#i_call">call</a></tt>'
				4358	or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
				4359	results.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4360
				4361	<h5>Arguments:</h5>
				4362
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4363	<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]	4364	first argument, or an undef value. The value must have <a
				4365	href="#t_struct">structure type</a>. The second argument is a constant
				4366	unsigned index value which must be in range for the number of values returned
				4367	by the call.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4368
				4369	<h5>Semantics:</h5>
				4370
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4371	<p>The '<tt>getresult</tt>' instruction extracts the element identified by
				4372	'<tt>index</tt>' from the aggregate value.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4373
				4374	<h5>Example:</h5>
				4375
				4376	<pre>
				4377	%struct.A = type { i32, i8 }
				4378
				4379	%r = call %struct.A @foo()
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4380	%gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
				4381	%gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4382	add i32 %gr, 42
				4383	add i8 %gr1, 41
				4384	</pre>
				4385
				4386	</div>
				4387
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4388	<!-- *********************************************************************** -->
				4389	<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
				4390	<!-- *********************************************************************** -->
				4391
				4392	<div class="doc_text">
				4393
				4394	<p>LLVM supports the notion of an "intrinsic function". These functions have
				4395	well known names and semantics and are required to follow certain restrictions.
				4396	Overall, these intrinsics represent an extension mechanism for the LLVM
				4397	language that does not require changing all of the transformations in LLVM when
				4398	adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
				4399
				4400	<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
				4401	prefix is reserved in LLVM for intrinsic names; thus, function names may not
				4402	begin with this prefix. Intrinsic functions must always be external functions:
				4403	you cannot define the body of intrinsic functions. Intrinsic functions may
				4404	only be used in call or invoke instructions: it is illegal to take the address
				4405	of an intrinsic function. Additionally, because intrinsic functions are part
				4406	of the LLVM language, it is required if any are added that they be documented
				4407	here.</p>
				4408
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4409	<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
				4410	a family of functions that perform the same operation but on different data
				4411	types. Because LLVM can represent over 8 million different integer types,
				4412	overloading is used commonly to allow an intrinsic function to operate on any
				4413	integer type. One or more of the argument types or the result type can be
				4414	overloaded to accept any integer type. Argument types may also be defined as
				4415	exactly matching a previous argument's type or the result type. This allows an
				4416	intrinsic function which accepts multiple arguments, but needs all of them to
				4417	be of the same type, to only be overloaded with respect to a single argument or
				4418	the result.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4419
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4420	<p>Overloaded intrinsics will have the names of its overloaded argument types
				4421	encoded into its function name, each preceded by a period. Only those types
				4422	which are overloaded result in a name suffix. Arguments whose type is matched
				4423	against another type do not. For example, the <tt>llvm.ctpop</tt> function can
				4424	take an integer of any width and returns an integer of exactly the same integer
				4425	width. This leads to a family of functions such as
				4426	<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
				4427	Only one type, the return type, is overloaded, and only one type suffix is
				4428	required. Because the argument's type is matched against the return type, it
				4429	does not require its own name suffix.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4430
				4431	<p>To learn how to add an intrinsic function, please see the
				4432	<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
				4433	</p>
				4434
				4435	</div>
				4436
				4437	<!-- ======================================================================= -->
				4438	<div class="doc_subsection">
				4439	<a name="int_varargs">Variable Argument Handling Intrinsics</a>
				4440	</div>
				4441
				4442	<div class="doc_text">
				4443
				4444	<p>Variable argument support is defined in LLVM with the <a
				4445	href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
				4446	intrinsic functions. These functions are related to the similarly
				4447	named macros defined in the <tt><stdarg.h></tt> header file.</p>
				4448
				4449	<p>All of these functions operate on arguments that use a
				4450	target-specific value type "<tt>va_list</tt>". The LLVM assembly
				4451	language reference manual does not define what this type is, so all
				4452	transformations should be prepared to handle these functions regardless of
				4453	the type used.</p>
				4454
				4455	<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
				4456	instruction and the variable argument handling intrinsic functions are
				4457	used.</p>
				4458
				4459	<div class="doc_code">
				4460	<pre>
				4461	define i32 @test(i32 %X, ...) {
				4462	; Initialize variable argument processing
				4463	%ap = alloca i8*
				4464	%ap2 = bitcast i8** %ap to i8*
				4465	call void @llvm.va_start(i8* %ap2)
				4466
				4467	; Read a single integer argument
				4468	%tmp = va_arg i8** %ap, i32
				4469
				4470	; Demonstrate usage of llvm.va_copy and llvm.va_end
				4471	%aq = alloca i8*
				4472	%aq2 = bitcast i8** %aq to i8*
				4473	call void @llvm.va_copy(i8* %aq2, i8* %ap2)
				4474	call void @llvm.va_end(i8* %aq2)
				4475
				4476	; Stop processing of arguments.
				4477	call void @llvm.va_end(i8* %ap2)
				4478	ret i32 %tmp
				4479	}
				4480
				4481	declare void @llvm.va_start(i8*)
				4482	declare void @llvm.va_copy(i8, i8)
				4483	declare void @llvm.va_end(i8*)
				4484	</pre>
				4485	</div>
				4486
				4487	</div>
				4488
				4489	<!-- _______________________________________________________________________ -->
				4490	<div class="doc_subsubsection">
				4491	<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
				4492	</div>
				4493
				4494
				4495	<div class="doc_text">
				4496	<h5>Syntax:</h5>
				4497	<pre> declare void %llvm.va_start(i8* <arglist>)<br></pre>
				4498	<h5>Overview:</h5>
				4499	<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
				4500	<tt>*<arglist></tt> for subsequent use by <tt><a
				4501	href="#i_va_arg">va_arg</a></tt>.</p>
				4502
				4503	<h5>Arguments:</h5>
				4504
				4505	<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
				4506
				4507	<h5>Semantics:</h5>
				4508
				4509	<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
				4510	macro available in C. In a target-dependent way, it initializes the
				4511	<tt>va_list</tt> element to which the argument points, so that the next call to
				4512	<tt>va_arg</tt> will produce the first variable argument passed to the function.
				4513	Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
				4514	last argument of the function as the compiler can figure that out.</p>
				4515
				4516	</div>
				4517
				4518	<!-- _______________________________________________________________________ -->
				4519	<div class="doc_subsubsection">
				4520	<a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
				4521	</div>
				4522
				4523	<div class="doc_text">
				4524	<h5>Syntax:</h5>
				4525	<pre> declare void @llvm.va_end(i8* <arglist>)<br></pre>
				4526	<h5>Overview:</h5>
				4527
				4528	<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
				4529	which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
				4530	or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
				4531
				4532	<h5>Arguments:</h5>
				4533
				4534	<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
				4535
				4536	<h5>Semantics:</h5>
				4537
				4538	<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
				4539	macro available in C. In a target-dependent way, it destroys the
				4540	<tt>va_list</tt> element to which the argument points. Calls to <a
				4541	href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
				4542	<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
				4543	<tt>llvm.va_end</tt>.</p>
				4544
				4545	</div>
				4546
				4547	<!-- _______________________________________________________________________ -->
				4548	<div class="doc_subsubsection">
				4549	<a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
				4550	</div>
				4551
				4552	<div class="doc_text">
				4553
				4554	<h5>Syntax:</h5>
				4555
				4556	<pre>
				4557	declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)
				4558	</pre>
				4559
				4560	<h5>Overview:</h5>
				4561
				4562	<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
				4563	from the source argument list to the destination argument list.</p>
				4564
				4565	<h5>Arguments:</h5>
				4566
				4567	<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
				4568	The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
				4569
				4570
				4571	<h5>Semantics:</h5>
				4572
				4573	<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
				4574	macro available in C. In a target-dependent way, it copies the source
				4575	<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
				4576	intrinsic is necessary because the <tt><a href="#int_va_start">
				4577	llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
				4578	example, memory allocation.</p>
				4579
				4580	</div>
				4581
				4582	<!-- ======================================================================= -->
				4583	<div class="doc_subsection">
				4584	<a name="int_gc">Accurate Garbage Collection Intrinsics</a>
				4585	</div>
				4586
				4587	<div class="doc_text">
				4588
				4589	<p>
				4590	LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	4591	Collection</a> (GC) requires the implementation and generation of these
				4592	intrinsics.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4593	These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
				4594	stack</a>, as well as garbage collector implementations that require <a
				4595	href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
				4596	Front-ends for type-safe garbage collected languages should generate these
				4597	intrinsics to make use of the LLVM garbage collectors. For more details, see <a
				4598	href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
				4599	</p>
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	4600
				4601	<p>The garbage collection intrinsics only operate on objects in the generic
				4602	address space (address space zero).</p>
				4603
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4604	</div>
				4605
				4606	<!-- _______________________________________________________________________ -->
				4607	<div class="doc_subsubsection">
				4608	<a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
				4609	</div>
				4610
				4611	<div class="doc_text">
				4612
				4613	<h5>Syntax:</h5>
				4614
				4615	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4616	declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4617	</pre>
				4618
				4619	<h5>Overview:</h5>
				4620
				4621	<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
				4622	the code generator, and allows some metadata to be associated with it.</p>
				4623
				4624	<h5>Arguments:</h5>
				4625
				4626	<p>The first argument specifies the address of a stack object that contains the
				4627	root pointer. The second pointer (which must be either a constant or a global
				4628	value address) contains the meta-data to be associated with the root.</p>
				4629
				4630	<h5>Semantics:</h5>
				4631
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	4632	<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]	4633	location. At compile-time, the code generator generates information to allow
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4634	the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
				4635	intrinsic may only be used in a function which <a href="#gc">specifies a GC
				4636	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4637
				4638	</div>
				4639
				4640
				4641	<!-- _______________________________________________________________________ -->
				4642	<div class="doc_subsubsection">
				4643	<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
				4644	</div>
				4645
				4646	<div class="doc_text">
				4647
				4648	<h5>Syntax:</h5>
				4649
				4650	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4651	declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4652	</pre>
				4653
				4654	<h5>Overview:</h5>
				4655
				4656	<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
				4657	locations, allowing garbage collector implementations that require read
				4658	barriers.</p>
				4659
				4660	<h5>Arguments:</h5>
				4661
				4662	<p>The second argument is the address to read from, which should be an address
				4663	allocated from the garbage collector. The first object is a pointer to the
				4664	start of the referenced object, if needed by the language runtime (otherwise
				4665	null).</p>
				4666
				4667	<h5>Semantics:</h5>
				4668
				4669	<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
				4670	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4671	garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
				4672	may only be used in a function which <a href="#gc">specifies a GC
				4673	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4674
				4675	</div>
				4676
				4677
				4678	<!-- _______________________________________________________________________ -->
				4679	<div class="doc_subsubsection">
				4680	<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
				4681	</div>
				4682
				4683	<div class="doc_text">
				4684
				4685	<h5>Syntax:</h5>
				4686
				4687	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4688	declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4689	</pre>
				4690
				4691	<h5>Overview:</h5>
				4692
				4693	<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
				4694	locations, allowing garbage collector implementations that require write
				4695	barriers (such as generational or reference counting collectors).</p>
				4696
				4697	<h5>Arguments:</h5>
				4698
				4699	<p>The first argument is the reference to store, the second is the start of the
				4700	object to store it to, and the third is the address of the field of Obj to
				4701	store to. If the runtime does not require a pointer to the object, Obj may be
				4702	null.</p>
				4703
				4704	<h5>Semantics:</h5>
				4705
				4706	<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
				4707	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4708	garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
				4709	may only be used in a function which <a href="#gc">specifies a GC
				4710	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4711
				4712	</div>
				4713
				4714
				4715
				4716	<!-- ======================================================================= -->
				4717	<div class="doc_subsection">
				4718	<a name="int_codegen">Code Generator Intrinsics</a>
				4719	</div>
				4720
				4721	<div class="doc_text">
				4722	<p>
				4723	These intrinsics are provided by LLVM to expose special features that may only
				4724	be implemented with code generator support.
				4725	</p>
				4726
				4727	</div>
				4728
				4729	<!-- _______________________________________________________________________ -->
				4730	<div class="doc_subsubsection">
				4731	<a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
				4732	</div>
				4733
				4734	<div class="doc_text">
				4735
				4736	<h5>Syntax:</h5>
				4737	<pre>
				4738	declare i8 *@llvm.returnaddress(i32 <level>)
				4739	</pre>
				4740
				4741	<h5>Overview:</h5>
				4742
				4743	<p>
				4744	The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
				4745	target-specific value indicating the return address of the current function
				4746	or one of its callers.
				4747	</p>
				4748
				4749	<h5>Arguments:</h5>
				4750
				4751	<p>
				4752	The argument to this intrinsic indicates which function to return the address
				4753	for. Zero indicates the calling function, one indicates its caller, etc. The
				4754	argument is <b>required</b> to be a constant integer value.
				4755	</p>
				4756
				4757	<h5>Semantics:</h5>
				4758
				4759	<p>
				4760	The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
				4761	the return address of the specified call frame, or zero if it cannot be
				4762	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4763	for arguments other than zero, so it should only be used for debugging purposes.
				4764	</p>
				4765
				4766	<p>
				4767	Note that calling this intrinsic does not prevent function inlining or other
				4768	aggressive transformations, so the value returned may not be that of the obvious
				4769	source-language caller.
				4770	</p>
				4771	</div>
				4772
				4773
				4774	<!-- _______________________________________________________________________ -->
				4775	<div class="doc_subsubsection">
				4776	<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
				4777	</div>
				4778
				4779	<div class="doc_text">
				4780
				4781	<h5>Syntax:</h5>
				4782	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4783	declare i8 *@llvm.frameaddress(i32 <level>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4784	</pre>
				4785
				4786	<h5>Overview:</h5>
				4787
				4788	<p>
				4789	The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
				4790	target-specific frame pointer value for the specified stack frame.
				4791	</p>
				4792
				4793	<h5>Arguments:</h5>
				4794
				4795	<p>
				4796	The argument to this intrinsic indicates which function to return the frame
				4797	pointer for. Zero indicates the calling function, one indicates its caller,
				4798	etc. The argument is <b>required</b> to be a constant integer value.
				4799	</p>
				4800
				4801	<h5>Semantics:</h5>
				4802
				4803	<p>
				4804	The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
				4805	the frame address of the specified call frame, or zero if it cannot be
				4806	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4807	for arguments other than zero, so it should only be used for debugging purposes.
				4808	</p>
				4809
				4810	<p>
				4811	Note that calling this intrinsic does not prevent function inlining or other
				4812	aggressive transformations, so the value returned may not be that of the obvious
				4813	source-language caller.
				4814	</p>
				4815	</div>
				4816
				4817	<!-- _______________________________________________________________________ -->
				4818	<div class="doc_subsubsection">
				4819	<a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
				4820	</div>
				4821
				4822	<div class="doc_text">
				4823
				4824	<h5>Syntax:</h5>
				4825	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4826	declare i8 *@llvm.stacksave()
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4827	</pre>
				4828
				4829	<h5>Overview:</h5>
				4830
				4831	<p>
				4832	The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
				4833	the function stack, for use with <a href="#int_stackrestore">
				4834	<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
				4835	features like scoped automatic variable sized arrays in C99.
				4836	</p>
				4837
				4838	<h5>Semantics:</h5>
				4839
				4840	<p>
				4841	This intrinsic returns a opaque pointer value that can be passed to <a
				4842	href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
				4843	<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
				4844	<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
				4845	state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
				4846	practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
				4847	that were allocated after the <tt>llvm.stacksave</tt> was executed.
				4848	</p>
				4849
				4850	</div>
				4851
				4852	<!-- _______________________________________________________________________ -->
				4853	<div class="doc_subsubsection">
				4854	<a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
				4855	</div>
				4856
				4857	<div class="doc_text">
				4858
				4859	<h5>Syntax:</h5>
				4860	<pre>
				4861	declare void @llvm.stackrestore(i8 * %ptr)
				4862	</pre>
				4863
				4864	<h5>Overview:</h5>
				4865
				4866	<p>
				4867	The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
				4868	the function stack to the state it was in when the corresponding <a
				4869	href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
				4870	useful for implementing language features like scoped automatic variable sized
				4871	arrays in C99.
				4872	</p>
				4873
				4874	<h5>Semantics:</h5>
				4875
				4876	<p>
				4877	See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
				4878	</p>
				4879
				4880	</div>
				4881
				4882
				4883	<!-- _______________________________________________________________________ -->
				4884	<div class="doc_subsubsection">
				4885	<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
				4886	</div>
				4887
				4888	<div class="doc_text">
				4889
				4890	<h5>Syntax:</h5>
				4891	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4892	declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4893	</pre>
				4894
				4895	<h5>Overview:</h5>
				4896
				4897
				4898	<p>
				4899	The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
				4900	a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
				4901	no
				4902	effect on the behavior of the program but can change its performance
				4903	characteristics.
				4904	</p>
				4905
				4906	<h5>Arguments:</h5>
				4907
				4908	<p>
				4909	<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
				4910	determining if the fetch should be for a read (0) or write (1), and
				4911	<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
				4912	locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
				4913	<tt>locality</tt> arguments must be constant integers.
				4914	</p>
				4915
				4916	<h5>Semantics:</h5>
				4917
				4918	<p>
				4919	This intrinsic does not modify the behavior of the program. In particular,
				4920	prefetches cannot trap and do not produce a value. On targets that support this
				4921	intrinsic, the prefetch can provide hints to the processor cache for better
				4922	performance.
				4923	</p>
				4924
				4925	</div>
				4926
				4927	<!-- _______________________________________________________________________ -->
				4928	<div class="doc_subsubsection">
				4929	<a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
				4930	</div>
				4931
				4932	<div class="doc_text">
				4933
				4934	<h5>Syntax:</h5>
				4935	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4936	declare void @llvm.pcmarker(i32 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4937	</pre>
				4938
				4939	<h5>Overview:</h5>
				4940
				4941
				4942	<p>
				4943	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]	4944	(PC) in a region of
				4945	code to simulators and other tools. The method is target specific, but it is
				4946	expected that the marker will use exported symbols to transmit the PC of the
				4947	marker.
				4948	The marker makes no guarantees that it will remain with any specific instruction
				4949	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]	4950	optimizations. The intended use is to be inserted after optimizations to allow
				4951	correlations of simulation runs.
				4952	</p>
				4953
				4954	<h5>Arguments:</h5>
				4955
				4956	<p>
				4957	<tt>id</tt> is a numerical id identifying the marker.
				4958	</p>
				4959
				4960	<h5>Semantics:</h5>
				4961
				4962	<p>
				4963	This intrinsic does not modify the behavior of the program. Backends that do not
				4964	support this intrinisic may ignore it.
				4965	</p>
				4966
				4967	</div>
				4968
				4969	<!-- _______________________________________________________________________ -->
				4970	<div class="doc_subsubsection">
				4971	<a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
				4972	</div>
				4973
				4974	<div class="doc_text">
				4975
				4976	<h5>Syntax:</h5>
				4977	<pre>
				4978	declare i64 @llvm.readcyclecounter( )
				4979	</pre>
				4980
				4981	<h5>Overview:</h5>
				4982
				4983
				4984	<p>
				4985	The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
				4986	counter register (or similar low latency, high accuracy clocks) on those targets
				4987	that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
				4988	As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
				4989	should only be used for small timings.
				4990	</p>
				4991
				4992	<h5>Semantics:</h5>
				4993
				4994	<p>
				4995	When directly supported, reading the cycle counter should not modify any memory.
				4996	Implementations are allowed to either return a application specific value or a
				4997	system wide value. On backends without support, this is lowered to a constant 0.
				4998	</p>
				4999
				5000	</div>
				5001
				5002	<!-- ======================================================================= -->
				5003	<div class="doc_subsection">
				5004	<a name="int_libc">Standard C Library Intrinsics</a>
				5005	</div>
				5006
				5007	<div class="doc_text">
				5008	<p>
				5009	LLVM provides intrinsics for a few important standard C library functions.
				5010	These intrinsics allow source-language front-ends to pass information about the
				5011	alignment of the pointer arguments to the code generator, providing opportunity
				5012	for more efficient code generation.
				5013	</p>
				5014
				5015	</div>
				5016
				5017	<!-- _______________________________________________________________________ -->
				5018	<div class="doc_subsubsection">
				5019	<a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
				5020	</div>
				5021
				5022	<div class="doc_text">
				5023
				5024	<h5>Syntax:</h5>
				5025	<pre>
				5026	declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
				5027	i32 <len>, i32 <align>)
				5028	declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>,
				5029	i64 <len>, i32 <align>)
				5030	</pre>
				5031
				5032	<h5>Overview:</h5>
				5033
				5034	<p>
				5035	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5036	location to the destination location.
				5037	</p>
				5038
				5039	<p>
				5040	Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
				5041	intrinsics do not return a value, and takes an extra alignment argument.
				5042	</p>
				5043
				5044	<h5>Arguments:</h5>
				5045
				5046	<p>
				5047	The first argument is a pointer to the destination, the second is a pointer to
				5048	the source. The third argument is an integer argument
				5049	specifying the number of bytes to copy, and the fourth argument is the alignment
				5050	of the source and destination locations.
				5051	</p>
				5052
				5053	<p>
				5054	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5055	the caller guarantees that both the source and destination pointers are aligned
				5056	to that boundary.
				5057	</p>
				5058
				5059	<h5>Semantics:</h5>
				5060
				5061	<p>
				5062	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5063	location to the destination location, which are not allowed to overlap. It
				5064	copies "len" bytes of memory over. If the argument is known to be aligned to
				5065	some boundary, this can be specified as the fourth argument, otherwise it should
				5066	be set to 0 or 1.
				5067	</p>
				5068	</div>
				5069
				5070
				5071	<!-- _______________________________________________________________________ -->
				5072	<div class="doc_subsubsection">
				5073	<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
				5074	</div>
				5075
				5076	<div class="doc_text">
				5077
				5078	<h5>Syntax:</h5>
				5079	<pre>
				5080	declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
				5081	i32 <len>, i32 <align>)
				5082	declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>,
				5083	i64 <len>, i32 <align>)
				5084	</pre>
				5085
				5086	<h5>Overview:</h5>
				5087
				5088	<p>
				5089	The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
				5090	location to the destination location. It is similar to the
Chris Lattner	dba16ea	2008-01-06 19:51:52 +0000	[diff] [blame]	5091	'<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]	5092	</p>
				5093
				5094	<p>
				5095	Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
				5096	intrinsics do not return a value, and takes an extra alignment argument.
				5097	</p>
				5098
				5099	<h5>Arguments:</h5>
				5100
				5101	<p>
				5102	The first argument is a pointer to the destination, the second is a pointer to
				5103	the source. The third argument is an integer argument
				5104	specifying the number of bytes to copy, and the fourth argument is the alignment
				5105	of the source and destination locations.
				5106	</p>
				5107
				5108	<p>
				5109	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5110	the caller guarantees that the source and destination pointers are aligned to
				5111	that boundary.
				5112	</p>
				5113
				5114	<h5>Semantics:</h5>
				5115
				5116	<p>
				5117	The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
				5118	location to the destination location, which may overlap. It
				5119	copies "len" bytes of memory over. If the argument is known to be aligned to
				5120	some boundary, this can be specified as the fourth argument, otherwise it should
				5121	be set to 0 or 1.
				5122	</p>
				5123	</div>
				5124
				5125
				5126	<!-- _______________________________________________________________________ -->
				5127	<div class="doc_subsubsection">
				5128	<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
				5129	</div>
				5130
				5131	<div class="doc_text">
				5132
				5133	<h5>Syntax:</h5>
				5134	<pre>
				5135	declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
				5136	i32 <len>, i32 <align>)
				5137	declare void @llvm.memset.i64(i8 * <dest>, i8 <val>,
				5138	i64 <len>, i32 <align>)
				5139	</pre>
				5140
				5141	<h5>Overview:</h5>
				5142
				5143	<p>
				5144	The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
				5145	byte value.
				5146	</p>
				5147
				5148	<p>
				5149	Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
				5150	does not return a value, and takes an extra alignment argument.
				5151	</p>
				5152
				5153	<h5>Arguments:</h5>
				5154
				5155	<p>
				5156	The first argument is a pointer to the destination to fill, the second is the
				5157	byte value to fill it with, the third argument is an integer
				5158	argument specifying the number of bytes to fill, and the fourth argument is the
				5159	known alignment of destination location.
				5160	</p>
				5161
				5162	<p>
				5163	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5164	the caller guarantees that the destination pointer is aligned to that boundary.
				5165	</p>
				5166
				5167	<h5>Semantics:</h5>
				5168
				5169	<p>
				5170	The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
				5171	the
				5172	destination location. If the argument is known to be aligned to some boundary,
				5173	this can be specified as the fourth argument, otherwise it should be set to 0 or
				5174	1.
				5175	</p>
				5176	</div>
				5177
				5178
				5179	<!-- _______________________________________________________________________ -->
				5180	<div class="doc_subsubsection">
				5181	<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
				5182	</div>
				5183
				5184	<div class="doc_text">
				5185
				5186	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5187	<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]	5188	floating point or vector of floating point type. Not all targets support all
				5189	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5190	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5191	declare float @llvm.sqrt.f32(float %Val)
				5192	declare double @llvm.sqrt.f64(double %Val)
				5193	declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
				5194	declare fp128 @llvm.sqrt.f128(fp128 %Val)
				5195	declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5196	</pre>
				5197
				5198	<h5>Overview:</h5>
				5199
				5200	<p>
				5201	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]	5202	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]	5203	<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]	5204	negative numbers other than -0.0 (which allows for better optimization, because
				5205	there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
				5206	defined to return -0.0 like IEEE sqrt.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5207	</p>
				5208
				5209	<h5>Arguments:</h5>
				5210
				5211	<p>
				5212	The argument and return value are floating point numbers of the same type.
				5213	</p>
				5214
				5215	<h5>Semantics:</h5>
				5216
				5217	<p>
				5218	This function returns the sqrt of the specified operand if it is a nonnegative
				5219	floating point number.
				5220	</p>
				5221	</div>
				5222
				5223	<!-- _______________________________________________________________________ -->
				5224	<div class="doc_subsubsection">
				5225	<a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
				5226	</div>
				5227
				5228	<div class="doc_text">
				5229
				5230	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5231	<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]	5232	floating point or vector of floating point type. Not all targets support all
				5233	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5234	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5235	declare float @llvm.powi.f32(float %Val, i32 %power)
				5236	declare double @llvm.powi.f64(double %Val, i32 %power)
				5237	declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
				5238	declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
				5239	declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5240	</pre>
				5241
				5242	<h5>Overview:</h5>
				5243
				5244	<p>
				5245	The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
				5246	specified (positive or negative) power. The order of evaluation of
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5247	multiplications is not defined. When a vector of floating point type is
				5248	used, the second argument remains a scalar integer value.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5249	</p>
				5250
				5251	<h5>Arguments:</h5>
				5252
				5253	<p>
				5254	The second argument is an integer power, and the first is a value to raise to
				5255	that power.
				5256	</p>
				5257
				5258	<h5>Semantics:</h5>
				5259
				5260	<p>
				5261	This function returns the first value raised to the second power with an
				5262	unspecified sequence of rounding operations.</p>
				5263	</div>
				5264
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5265	<!-- _______________________________________________________________________ -->
				5266	<div class="doc_subsubsection">
				5267	<a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
				5268	</div>
				5269
				5270	<div class="doc_text">
				5271
				5272	<h5>Syntax:</h5>
				5273	<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
				5274	floating point or vector of floating point type. Not all targets support all
				5275	types however.
				5276	<pre>
				5277	declare float @llvm.sin.f32(float %Val)
				5278	declare double @llvm.sin.f64(double %Val)
				5279	declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
				5280	declare fp128 @llvm.sin.f128(fp128 %Val)
				5281	declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
				5282	</pre>
				5283
				5284	<h5>Overview:</h5>
				5285
				5286	<p>
				5287	The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
				5288	</p>
				5289
				5290	<h5>Arguments:</h5>
				5291
				5292	<p>
				5293	The argument and return value are floating point numbers of the same type.
				5294	</p>
				5295
				5296	<h5>Semantics:</h5>
				5297
				5298	<p>
				5299	This function returns the sine of the specified operand, returning the
				5300	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]	5301	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5302	</div>
				5303
				5304	<!-- _______________________________________________________________________ -->
				5305	<div class="doc_subsubsection">
				5306	<a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
				5307	</div>
				5308
				5309	<div class="doc_text">
				5310
				5311	<h5>Syntax:</h5>
				5312	<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
				5313	floating point or vector of floating point type. Not all targets support all
				5314	types however.
				5315	<pre>
				5316	declare float @llvm.cos.f32(float %Val)
				5317	declare double @llvm.cos.f64(double %Val)
				5318	declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
				5319	declare fp128 @llvm.cos.f128(fp128 %Val)
				5320	declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
				5321	</pre>
				5322
				5323	<h5>Overview:</h5>
				5324
				5325	<p>
				5326	The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
				5327	</p>
				5328
				5329	<h5>Arguments:</h5>
				5330
				5331	<p>
				5332	The argument and return value are floating point numbers of the same type.
				5333	</p>
				5334
				5335	<h5>Semantics:</h5>
				5336
				5337	<p>
				5338	This function returns the cosine of the specified operand, returning the
				5339	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]	5340	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5341	</div>
				5342
				5343	<!-- _______________________________________________________________________ -->
				5344	<div class="doc_subsubsection">
				5345	<a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
				5346	</div>
				5347
				5348	<div class="doc_text">
				5349
				5350	<h5>Syntax:</h5>
				5351	<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
				5352	floating point or vector of floating point type. Not all targets support all
				5353	types however.
				5354	<pre>
				5355	declare float @llvm.pow.f32(float %Val, float %Power)
				5356	declare double @llvm.pow.f64(double %Val, double %Power)
				5357	declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
				5358	declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
				5359	declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
				5360	</pre>
				5361
				5362	<h5>Overview:</h5>
				5363
				5364	<p>
				5365	The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
				5366	specified (positive or negative) power.
				5367	</p>
				5368
				5369	<h5>Arguments:</h5>
				5370
				5371	<p>
				5372	The second argument is a floating point power, and the first is a value to
				5373	raise to that power.
				5374	</p>
				5375
				5376	<h5>Semantics:</h5>
				5377
				5378	<p>
				5379	This function returns the first value raised to the second power,
				5380	returning the
				5381	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]	5382	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5383	</div>
				5384
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5385
				5386	<!-- ======================================================================= -->
				5387	<div class="doc_subsection">
				5388	<a name="int_manip">Bit Manipulation Intrinsics</a>
				5389	</div>
				5390
				5391	<div class="doc_text">
				5392	<p>
				5393	LLVM provides intrinsics for a few important bit manipulation operations.
				5394	These allow efficient code generation for some algorithms.
				5395	</p>
				5396
				5397	</div>
				5398
				5399	<!-- _______________________________________________________________________ -->
				5400	<div class="doc_subsubsection">
				5401	<a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
				5402	</div>
				5403
				5404	<div class="doc_text">
				5405
				5406	<h5>Syntax:</h5>
				5407	<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]	5408	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]	5409	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5410	declare i16 @llvm.bswap.i16(i16 <id>)
				5411	declare i32 @llvm.bswap.i32(i32 <id>)
				5412	declare i64 @llvm.bswap.i64(i64 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5413	</pre>
				5414
				5415	<h5>Overview:</h5>
				5416
				5417	<p>
				5418	The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
				5419	values with an even number of bytes (positive multiple of 16 bits). These are
				5420	useful for performing operations on data that is not in the target's native
				5421	byte order.
				5422	</p>
				5423
				5424	<h5>Semantics:</h5>
				5425
				5426	<p>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5427	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]	5428	and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
				5429	intrinsic returns an i32 value that has the four bytes of the input i32
				5430	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]	5431	i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
				5432	<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5433	additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
				5434	</p>
				5435
				5436	</div>
				5437
				5438	<!-- _______________________________________________________________________ -->
				5439	<div class="doc_subsubsection">
				5440	<a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
				5441	</div>
				5442
				5443	<div class="doc_text">
				5444
				5445	<h5>Syntax:</h5>
				5446	<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
				5447	width. Not all targets support all bit widths however.
				5448	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5449	declare i8 @llvm.ctpop.i8 (i8 <src>)
				5450	declare i16 @llvm.ctpop.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5451	declare i32 @llvm.ctpop.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5452	declare i64 @llvm.ctpop.i64(i64 <src>)
				5453	declare i256 @llvm.ctpop.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5454	</pre>
				5455
				5456	<h5>Overview:</h5>
				5457
				5458	<p>
				5459	The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
				5460	value.
				5461	</p>
				5462
				5463	<h5>Arguments:</h5>
				5464
				5465	<p>
				5466	The only argument is the value to be counted. The argument may be of any
				5467	integer type. The return type must match the argument type.
				5468	</p>
				5469
				5470	<h5>Semantics:</h5>
				5471
				5472	<p>
				5473	The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
				5474	</p>
				5475	</div>
				5476
				5477	<!-- _______________________________________________________________________ -->
				5478	<div class="doc_subsubsection">
				5479	<a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
				5480	</div>
				5481
				5482	<div class="doc_text">
				5483
				5484	<h5>Syntax:</h5>
				5485	<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
				5486	integer bit width. Not all targets support all bit widths however.
				5487	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5488	declare i8 @llvm.ctlz.i8 (i8 <src>)
				5489	declare i16 @llvm.ctlz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5490	declare i32 @llvm.ctlz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5491	declare i64 @llvm.ctlz.i64(i64 <src>)
				5492	declare i256 @llvm.ctlz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5493	</pre>
				5494
				5495	<h5>Overview:</h5>
				5496
				5497	<p>
				5498	The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
				5499	leading zeros in a variable.
				5500	</p>
				5501
				5502	<h5>Arguments:</h5>
				5503
				5504	<p>
				5505	The only argument is the value to be counted. The argument may be of any
				5506	integer type. The return type must match the argument type.
				5507	</p>
				5508
				5509	<h5>Semantics:</h5>
				5510
				5511	<p>
				5512	The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
				5513	in a variable. If the src == 0 then the result is the size in bits of the type
				5514	of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
				5515	</p>
				5516	</div>
				5517
				5518
				5519
				5520	<!-- _______________________________________________________________________ -->
				5521	<div class="doc_subsubsection">
				5522	<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
				5523	</div>
				5524
				5525	<div class="doc_text">
				5526
				5527	<h5>Syntax:</h5>
				5528	<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
				5529	integer bit width. Not all targets support all bit widths however.
				5530	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5531	declare i8 @llvm.cttz.i8 (i8 <src>)
				5532	declare i16 @llvm.cttz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5533	declare i32 @llvm.cttz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5534	declare i64 @llvm.cttz.i64(i64 <src>)
				5535	declare i256 @llvm.cttz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5536	</pre>
				5537
				5538	<h5>Overview:</h5>
				5539
				5540	<p>
				5541	The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
				5542	trailing zeros.
				5543	</p>
				5544
				5545	<h5>Arguments:</h5>
				5546
				5547	<p>
				5548	The only argument is the value to be counted. The argument may be of any
				5549	integer type. The return type must match the argument type.
				5550	</p>
				5551
				5552	<h5>Semantics:</h5>
				5553
				5554	<p>
				5555	The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
				5556	in a variable. If the src == 0 then the result is the size in bits of the type
				5557	of src. For example, <tt>llvm.cttz(2) = 1</tt>.
				5558	</p>
				5559	</div>
				5560
				5561	<!-- _______________________________________________________________________ -->
				5562	<div class="doc_subsubsection">
				5563	<a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
				5564	</div>
				5565
				5566	<div class="doc_text">
				5567
				5568	<h5>Syntax:</h5>
				5569	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
				5570	on any integer bit width.
				5571	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5572	declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
				5573	declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5574	</pre>
				5575
				5576	<h5>Overview:</h5>
				5577	<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
				5578	range of bits from an integer value and returns them in the same bit width as
				5579	the original value.</p>
				5580
				5581	<h5>Arguments:</h5>
				5582	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5583	any bit width but they must have the same bit width. The second and third
				5584	arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
				5585
				5586	<h5>Semantics:</h5>
				5587	<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
				5588	of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
				5589	<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
				5590	operates in forward mode.</p>
				5591	<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
				5592	right by <tt>%loBit</tt> bits and then ANDing it with a mask with
				5593	only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
				5594	<ol>
				5595	<li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
				5596	by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
				5597	<li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
				5598	to determine the number of bits to retain.</li>
				5599	<li>A mask of the retained bits is created by shifting a -1 value.</li>
				5600	<li>The mask is ANDed with <tt>%val</tt> to produce the result.
				5601	</ol>
				5602	<p>In reverse mode, a similar computation is made except that the bits are
				5603	returned in the reverse order. So, for example, if <tt>X</tt> has the value
				5604	<tt>i16 0x0ACF (101011001111)</tt> and we apply
				5605	<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
				5606	<tt>i16 0x0026 (000000100110)</tt>.</p>
				5607	</div>
				5608
				5609	<div class="doc_subsubsection">
				5610	<a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
				5611	</div>
				5612
				5613	<div class="doc_text">
				5614
				5615	<h5>Syntax:</h5>
				5616	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
				5617	on any integer bit width.
				5618	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5619	declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
				5620	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]	5621	</pre>
				5622
				5623	<h5>Overview:</h5>
				5624	<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
				5625	of bits in an integer value with another integer value. It returns the integer
				5626	with the replaced bits.</p>
				5627
				5628	<h5>Arguments:</h5>
				5629	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5630	any bit width but they must have the same bit width. <tt>%val</tt> is the value
				5631	whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
				5632	integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
				5633	type since they specify only a bit index.</p>
				5634
				5635	<h5>Semantics:</h5>
				5636	<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
				5637	of operation: forwards and reverse. If <tt>%lo</tt> is greater than
				5638	<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
				5639	operates in forward mode.</p>
				5640	<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
				5641	truncating it down to the size of the replacement area or zero extending it
				5642	up to that size.</p>
				5643	<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
				5644	are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
				5645	in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
				5646	to the <tt>%hi</tt>th bit.
				5647	<p>In reverse mode, a similar computation is made except that the bits are
				5648	reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
				5649	<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
				5650	<h5>Examples:</h5>
				5651	<pre>
				5652	llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
				5653	llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
				5654	llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F
				5655	llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
				5656	llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
				5657	</pre>
				5658	</div>
				5659
				5660	<!-- ======================================================================= -->
				5661	<div class="doc_subsection">
				5662	<a name="int_debugger">Debugger Intrinsics</a>
				5663	</div>
				5664
				5665	<div class="doc_text">
				5666	<p>
				5667	The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
				5668	are described in the <a
				5669	href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
				5670	Debugging</a> document.
				5671	</p>
				5672	</div>
				5673
				5674
				5675	<!-- ======================================================================= -->
				5676	<div class="doc_subsection">
				5677	<a name="int_eh">Exception Handling Intrinsics</a>
				5678	</div>
				5679
				5680	<div class="doc_text">
				5681	<p> The LLVM exception handling intrinsics (which all start with
				5682	<tt>llvm.eh.</tt> prefix), are described in the <a
				5683	href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
				5684	Handling</a> document. </p>
				5685	</div>
				5686
				5687	<!-- ======================================================================= -->
				5688	<div class="doc_subsection">
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5689	<a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5690	</div>
				5691
				5692	<div class="doc_text">
				5693	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5694	This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5695	the <tt>nest</tt> attribute, from a function. The result is a callable
				5696	function pointer lacking the nest parameter - the caller does not need
				5697	to provide a value for it. Instead, the value to use is stored in
				5698	advance in a "trampoline", a block of memory usually allocated
				5699	on the stack, which also contains code to splice the nest value into the
				5700	argument list. This is used to implement the GCC nested function address
				5701	extension.
				5702	</p>
				5703	<p>
				5704	For example, if the function is
				5705	<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]	5706	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]	5707	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5708	%tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
				5709	%tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
				5710	%p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8), i8 %nval )
				5711	%fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5712	</pre>
Bill Wendling	e262b4c	2007-09-22 09:23:55 +0000	[diff] [blame]	5713	<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
				5714	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]	5715	</div>
				5716
				5717	<!-- _______________________________________________________________________ -->
				5718	<div class="doc_subsubsection">
				5719	<a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
				5720	</div>
				5721	<div class="doc_text">
				5722	<h5>Syntax:</h5>
				5723	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5724	declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5725	</pre>
				5726	<h5>Overview:</h5>
				5727	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5728	This fills the memory pointed to by <tt>tramp</tt> with code
				5729	and returns a function pointer suitable for executing it.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5730	</p>
				5731	<h5>Arguments:</h5>
				5732	<p>
				5733	The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
				5734	pointers. The <tt>tramp</tt> argument must point to a sufficiently large
				5735	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]	5736	intrinsic. Note that the size and the alignment are target-specific - LLVM
				5737	currently provides no portable way of determining them, so a front-end that
				5738	generates this intrinsic needs to have some target-specific knowledge.
				5739	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]	5740	</p>
				5741	<h5>Semantics:</h5>
				5742	<p>
				5743	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]	5744	dependent code, turning it into a function. A pointer to this function is
				5745	returned, but needs to be bitcast to an
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5746	<a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5747	before being called. The new function's signature is the same as that of
				5748	<tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
				5749	removed. At most one such <tt>nest</tt> argument is allowed, and it must be
				5750	of pointer type. Calling the new function is equivalent to calling
				5751	<tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
				5752	missing <tt>nest</tt> argument. If, after calling
				5753	<tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
				5754	modified, then the effect of any later call to the returned function pointer is
				5755	undefined.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5756	</p>
				5757	</div>
				5758
				5759	<!-- ======================================================================= -->
				5760	<div class="doc_subsection">
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5761	<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
				5762	</div>
				5763
				5764	<div class="doc_text">
				5765	<p>
				5766	These intrinsic functions expand the "universal IR" of LLVM to represent
				5767	hardware constructs for atomic operations and memory synchronization. This
				5768	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]	5769	is aimed at a low enough level to allow any programming models or APIs
				5770	(Application Programming Interfaces) which
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5771	need atomic behaviors to map cleanly onto it. It is also modeled primarily on
				5772	hardware behavior. Just as hardware provides a "universal IR" for source
				5773	languages, it also provides a starting point for developing a "universal"
				5774	atomic operation and synchronization IR.
				5775	</p>
				5776	<p>
				5777	These do <em>not</em> form an API such as high-level threading libraries,
				5778	software transaction memory systems, atomic primitives, and intrinsic
				5779	functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
				5780	application libraries. The hardware interface provided by LLVM should allow
				5781	a clean implementation of all of these APIs and parallel programming models.
				5782	No one model or paradigm should be selected above others unless the hardware
				5783	itself ubiquitously does so.
				5784
				5785	</p>
				5786	</div>
				5787
				5788	<!-- _______________________________________________________________________ -->
				5789	<div class="doc_subsubsection">
				5790	<a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
				5791	</div>
				5792	<div class="doc_text">
				5793	<h5>Syntax:</h5>
				5794	<pre>
				5795	declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>,
				5796	i1 <device> )
				5797
				5798	</pre>
				5799	<h5>Overview:</h5>
				5800	<p>
				5801	The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
				5802	specific pairs of memory access types.
				5803	</p>
				5804	<h5>Arguments:</h5>
				5805	<p>
				5806	The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
				5807	The first four arguments enables a specific barrier as listed below. The fith
				5808	argument specifies that the barrier applies to io or device or uncached memory.
				5809
				5810	</p>
				5811	<ul>
				5812	<li><tt>ll</tt>: load-load barrier</li>
				5813	<li><tt>ls</tt>: load-store barrier</li>
				5814	<li><tt>sl</tt>: store-load barrier</li>
				5815	<li><tt>ss</tt>: store-store barrier</li>
				5816	<li><tt>device</tt>: barrier applies to device and uncached memory also.
				5817	</ul>
				5818	<h5>Semantics:</h5>
				5819	<p>
				5820	This intrinsic causes the system to enforce some ordering constraints upon
				5821	the loads and stores of the program. This barrier does not indicate
				5822	<em>when</em> any events will occur, it only enforces an <em>order</em> in
				5823	which they occur. For any of the specified pairs of load and store operations
				5824	(f.ex. load-load, or store-load), all of the first operations preceding the
				5825	barrier will complete before any of the second operations succeeding the
				5826	barrier begin. Specifically the semantics for each pairing is as follows:
				5827	</p>
				5828	<ul>
				5829	<li><tt>ll</tt>: All loads before the barrier must complete before any load
				5830	after the barrier begins.</li>
				5831
				5832	<li><tt>ls</tt>: All loads before the barrier must complete before any
				5833	store after the barrier begins.</li>
				5834	<li><tt>ss</tt>: All stores before the barrier must complete before any
				5835	store after the barrier begins.</li>
				5836	<li><tt>sl</tt>: All stores before the barrier must complete before any
				5837	load after the barrier begins.</li>
				5838	</ul>
				5839	<p>
				5840	These semantics are applied with a logical "and" behavior when more than one
				5841	is enabled in a single memory barrier intrinsic.
				5842	</p>
				5843	<p>
				5844	Backends may implement stronger barriers than those requested when they do not
				5845	support as fine grained a barrier as requested. Some architectures do not
				5846	need all types of barriers and on such architectures, these become noops.
				5847	</p>
				5848	<h5>Example:</h5>
				5849	<pre>
				5850	%ptr = malloc i32
				5851	store i32 4, %ptr
				5852
				5853	%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
				5854	call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
				5855	<i>; guarantee the above finishes</i>
				5856	store i32 8, %ptr <i>; before this begins</i>
				5857	</pre>
				5858	</div>
				5859
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5860	<!-- _______________________________________________________________________ -->
				5861	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5862	<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]	5863	</div>
				5864	<div class="doc_text">
				5865	<h5>Syntax:</h5>
				5866	<p>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5867	This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
				5868	any integer bit width and for different address spaces. Not all targets
				5869	support all bit widths however.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5870
				5871	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5872	declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
				5873	declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
				5874	declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
				5875	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]	5876
				5877	</pre>
				5878	<h5>Overview:</h5>
				5879	<p>
				5880	This loads a value in memory and compares it to a given value. If they are
				5881	equal, it stores a new value into the memory.
				5882	</p>
				5883	<h5>Arguments:</h5>
				5884	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5885	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]	5886	well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
				5887	same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
				5888	this integer type. While any bit width integer may be used, targets may only
				5889	lower representations they support in hardware.
				5890
				5891	</p>
				5892	<h5>Semantics:</h5>
				5893	<p>
				5894	This entire intrinsic must be executed atomically. It first loads the value
				5895	in memory pointed to by <tt>ptr</tt> and compares it with the value
				5896	<tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
				5897	loaded value is yielded in all cases. This provides the equivalent of an
				5898	atomic compare-and-swap operation within the SSA framework.
				5899	</p>
				5900	<h5>Examples:</h5>
				5901
				5902	<pre>
				5903	%ptr = malloc i32
				5904	store i32 4, %ptr
				5905
				5906	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5907	%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]	5908	<i>; yields {i32}:result1 = 4</i>
				5909	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5910	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5911
				5912	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5913	%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]	5914	<i>; yields {i32}:result2 = 8</i>
				5915	%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
				5916
				5917	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
				5918	</pre>
				5919	</div>
				5920
				5921	<!-- _______________________________________________________________________ -->
				5922	<div class="doc_subsubsection">
				5923	<a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
				5924	</div>
				5925	<div class="doc_text">
				5926	<h5>Syntax:</h5>
				5927
				5928	<p>
				5929	This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
				5930	integer bit width. Not all targets support all bit widths however.</p>
				5931	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5932	declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
				5933	declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
				5934	declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
				5935	declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5936
				5937	</pre>
				5938	<h5>Overview:</h5>
				5939	<p>
				5940	This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
				5941	the value from memory. It then stores the value in <tt>val</tt> in the memory
				5942	at <tt>ptr</tt>.
				5943	</p>
				5944	<h5>Arguments:</h5>
				5945
				5946	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5947	The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5948	<tt>val</tt> argument and the result must be integers of the same bit width.
				5949	The first argument, <tt>ptr</tt>, must be a pointer to a value of this
				5950	integer type. The targets may only lower integer representations they
				5951	support.
				5952	</p>
				5953	<h5>Semantics:</h5>
				5954	<p>
				5955	This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
				5956	stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
				5957	equivalent of an atomic swap operation within the SSA framework.
				5958
				5959	</p>
				5960	<h5>Examples:</h5>
				5961	<pre>
				5962	%ptr = malloc i32
				5963	store i32 4, %ptr
				5964
				5965	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5966	%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5967	<i>; yields {i32}:result1 = 4</i>
				5968	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5969	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5970
				5971	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5972	%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5973	<i>; yields {i32}:result2 = 8</i>
				5974
				5975	%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
				5976	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
				5977	</pre>
				5978	</div>
				5979
				5980	<!-- _______________________________________________________________________ -->
				5981	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5982	<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]	5983
				5984	</div>
				5985	<div class="doc_text">
				5986	<h5>Syntax:</h5>
				5987	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5988	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]	5989	integer bit width. Not all targets support all bit widths however.</p>
				5990	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5991	declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
				5992	declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
				5993	declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
				5994	declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5995
				5996	</pre>
				5997	<h5>Overview:</h5>
				5998	<p>
				5999	This intrinsic adds <tt>delta</tt> to the value stored in memory at
				6000	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6001	</p>
				6002	<h5>Arguments:</h5>
				6003	<p>
				6004
				6005	The intrinsic takes two arguments, the first a pointer to an integer value
				6006	and the second an integer value. The result is also an integer value. These
				6007	integer types can have any bit width, but they must all have the same bit
				6008	width. The targets may only lower integer representations they support.
				6009	</p>
				6010	<h5>Semantics:</h5>
				6011	<p>
				6012	This intrinsic does a series of operations atomically. It first loads the
				6013	value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
				6014	to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6015	</p>
				6016
				6017	<h5>Examples:</h5>
				6018	<pre>
				6019	%ptr = malloc i32
				6020	store i32 4, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6021	%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]	6022	<i>; yields {i32}:result1 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6023	%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]	6024	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6025	%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]	6026	<i>; yields {i32}:result3 = 10</i>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6027	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6028	</pre>
				6029	</div>
				6030
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6031	<!-- _______________________________________________________________________ -->
				6032	<div class="doc_subsubsection">
				6033	<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
				6034
				6035	</div>
				6036	<div class="doc_text">
				6037	<h5>Syntax:</h5>
				6038	<p>
				6039	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]	6040	any integer bit width and for different address spaces. Not all targets
				6041	support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6042	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6043	declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
				6044	declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
				6045	declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
				6046	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]	6047
				6048	</pre>
				6049	<h5>Overview:</h5>
				6050	<p>
				6051	This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
				6052	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6053	</p>
				6054	<h5>Arguments:</h5>
				6055	<p>
				6056
				6057	The intrinsic takes two arguments, the first a pointer to an integer value
				6058	and the second an integer value. The result is also an integer value. These
				6059	integer types can have any bit width, but they must all have the same bit
				6060	width. The targets may only lower integer representations they support.
				6061	</p>
				6062	<h5>Semantics:</h5>
				6063	<p>
				6064	This intrinsic does a series of operations atomically. It first loads the
				6065	value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
				6066	result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6067	</p>
				6068
				6069	<h5>Examples:</h5>
				6070	<pre>
				6071	%ptr = malloc i32
				6072	store i32 8, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6073	%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]	6074	<i>; yields {i32}:result1 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6075	%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]	6076	<i>; yields {i32}:result2 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6077	%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]	6078	<i>; yields {i32}:result3 = 2</i>
				6079	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
				6080	</pre>
				6081	</div>
				6082
				6083	<!-- _______________________________________________________________________ -->
				6084	<div class="doc_subsubsection">
				6085	<a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
				6086	<a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
				6087	<a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
				6088	<a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
				6089
				6090	</div>
				6091	<div class="doc_text">
				6092	<h5>Syntax:</h5>
				6093	<p>
				6094	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
				6095	<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]	6096	<tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
				6097	address spaces. Not all targets support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6098	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6099	declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
				6100	declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
				6101	declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
				6102	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]	6103
				6104	</pre>
				6105
				6106	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6107	declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
				6108	declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
				6109	declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
				6110	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]	6111
				6112	</pre>
				6113
				6114	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6115	declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
				6116	declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
				6117	declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
				6118	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]	6119
				6120	</pre>
				6121
				6122	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6123	declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
				6124	declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
				6125	declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
				6126	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]	6127
				6128	</pre>
				6129	<h5>Overview:</h5>
				6130	<p>
				6131	These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
				6132	the value stored in memory at <tt>ptr</tt>. It yields the original value
				6133	at <tt>ptr</tt>.
				6134	</p>
				6135	<h5>Arguments:</h5>
				6136	<p>
				6137
				6138	These intrinsics take two arguments, the first a pointer to an integer value
				6139	and the second an integer value. The result is also an integer value. These
				6140	integer types can have any bit width, but they must all have the same bit
				6141	width. The targets may only lower integer representations they support.
				6142	</p>
				6143	<h5>Semantics:</h5>
				6144	<p>
				6145	These intrinsics does a series of operations atomically. They first load the
				6146	value stored at <tt>ptr</tt>. They then do the bitwise operation
				6147	<tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
				6148	value stored at <tt>ptr</tt>.
				6149	</p>
				6150
				6151	<h5>Examples:</h5>
				6152	<pre>
				6153	%ptr = malloc i32
				6154	store i32 0x0F0F, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6155	%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]	6156	<i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6157	%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]	6158	<i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6159	%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]	6160	<i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6161	%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]	6162	<i>; yields {i32}:result3 = FF</i>
				6163	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
				6164	</pre>
				6165	</div>
				6166
				6167
				6168	<!-- _______________________________________________________________________ -->
				6169	<div class="doc_subsubsection">
				6170	<a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
				6171	<a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
				6172	<a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
				6173	<a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
				6174
				6175	</div>
				6176	<div class="doc_text">
				6177	<h5>Syntax:</h5>
				6178	<p>
				6179	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
				6180	<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]	6181	<tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
				6182	address spaces. Not all targets
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6183	support all bit widths however.</p>
				6184	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6185	declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
				6186	declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
				6187	declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
				6188	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]	6189
				6190	</pre>
				6191
				6192	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6193	declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
				6194	declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
				6195	declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
				6196	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]	6197
				6198	</pre>
				6199
				6200	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6201	declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
				6202	declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
				6203	declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
				6204	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]	6205
				6206	</pre>
				6207
				6208	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6209	declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
				6210	declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
				6211	declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
				6212	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]	6213
				6214	</pre>
				6215	<h5>Overview:</h5>
				6216	<p>
				6217	These intrinsics takes the signed or unsigned minimum or maximum of
				6218	<tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
				6219	original value at <tt>ptr</tt>.
				6220	</p>
				6221	<h5>Arguments:</h5>
				6222	<p>
				6223
				6224	These intrinsics take two arguments, the first a pointer to an integer value
				6225	and the second an integer value. The result is also an integer value. These
				6226	integer types can have any bit width, but they must all have the same bit
				6227	width. The targets may only lower integer representations they support.
				6228	</p>
				6229	<h5>Semantics:</h5>
				6230	<p>
				6231	These intrinsics does a series of operations atomically. They first load the
				6232	value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
				6233	<tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
				6234	the original value stored at <tt>ptr</tt>.
				6235	</p>
				6236
				6237	<h5>Examples:</h5>
				6238	<pre>
				6239	%ptr = malloc i32
				6240	store i32 7, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6241	%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]	6242	<i>; yields {i32}:result0 = 7</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6243	%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]	6244	<i>; yields {i32}:result1 = -2</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6245	%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]	6246	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6247	%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]	6248	<i>; yields {i32}:result3 = 8</i>
				6249	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
				6250	</pre>
				6251	</div>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6252
				6253	<!-- ======================================================================= -->
				6254	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6255	<a name="int_general">General Intrinsics</a>
				6256	</div>
				6257
				6258	<div class="doc_text">
				6259	<p> This class of intrinsics is designed to be generic and has
				6260	no specific purpose. </p>
				6261	</div>
				6262
				6263	<!-- _______________________________________________________________________ -->
				6264	<div class="doc_subsubsection">
				6265	<a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
				6266	</div>
				6267
				6268	<div class="doc_text">
				6269
				6270	<h5>Syntax:</h5>
				6271	<pre>
				6272	declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> )
				6273	</pre>
				6274
				6275	<h5>Overview:</h5>
				6276
				6277	<p>
				6278	The '<tt>llvm.var.annotation</tt>' intrinsic
				6279	</p>
				6280
				6281	<h5>Arguments:</h5>
				6282
				6283	<p>
				6284	The first argument is a pointer to a value, the second is a pointer to a
				6285	global string, the third is a pointer to a global string which is the source
				6286	file name, and the last argument is the line number.
				6287	</p>
				6288
				6289	<h5>Semantics:</h5>
				6290
				6291	<p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6292	This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6293	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]	6294	annotations. These have no other defined use, they are ignored by code
				6295	generation and optimization.
				6296	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6297	</div>
				6298
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6299	<!-- _______________________________________________________________________ -->
				6300	<div class="doc_subsubsection">
Tanya Lattner	c9869b1	2007-09-21 23:57:59 +0000	[diff] [blame]	6301	<a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6302	</div>
				6303
				6304	<div class="doc_text">
				6305
				6306	<h5>Syntax:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6307	<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
				6308	any integer bit width.
				6309	</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6310	<pre>
Tanya Lattner	09161fe	2007-09-22 00:03:01 +0000	[diff] [blame]	6311	declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
				6312	declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
				6313	declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> )
				6314	declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> )
				6315	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]	6316	</pre>
				6317
				6318	<h5>Overview:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6319
				6320	<p>
				6321	The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6322	</p>
				6323
				6324	<h5>Arguments:</h5>
				6325
				6326	<p>
				6327	The first argument is an integer value (result of some expression),
				6328	the second is a pointer to a global string, the third is a pointer to a global
				6329	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]	6330	It returns the value of the first argument.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6331	</p>
				6332
				6333	<h5>Semantics:</h5>
				6334
				6335	<p>
				6336	This intrinsic allows annotations to be put on arbitrary expressions
				6337	with arbitrary strings. This can be useful for special purpose optimizations
				6338	that want to look for these annotations. These have no other defined use, they
				6339	are ignored by code generation and optimization.
				6340	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6341
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6342	<!-- _______________________________________________________________________ -->
				6343	<div class="doc_subsubsection">
				6344	<a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
				6345	</div>
				6346
				6347	<div class="doc_text">
				6348
				6349	<h5>Syntax:</h5>
				6350	<pre>
				6351	declare void @llvm.trap()
				6352	</pre>
				6353
				6354	<h5>Overview:</h5>
				6355
				6356	<p>
				6357	The '<tt>llvm.trap</tt>' intrinsic
				6358	</p>
				6359
				6360	<h5>Arguments:</h5>
				6361
				6362	<p>
				6363	None
				6364	</p>
				6365
				6366	<h5>Semantics:</h5>
				6367
				6368	<p>
				6369	This intrinsics is lowered to the target dependent trap instruction. If the
				6370	target does not have a trap instruction, this intrinsic will be lowered to the
				6371	call of the abort() function.
				6372	</p>
				6373	</div>
				6374
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6375	<!-- *********************************************************************** -->
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				6383	<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
				6384	<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
				6385	Last modified: $Date$
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