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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>
Dale Johannesen	c08a0e2	2008-09-25 20:47:45 +0000	[diff] [blame]	848	<dd>This indicates that this parameter or return value should be treated
				849	in a special target-dependent fashion during while emitting code for a
				850	function call or return (usually, by putting it in a register as opposed
				851	to memory; in some places it is used to distinguish between two different
				852	kinds of registers). Use of this attribute is target-specific</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	853
				854	<dt><tt>byval</tt></dt>
Chris Lattner	04c8618	2008-01-15 04:34:22 +0000	[diff] [blame]	855	<dd>This indicates that the pointer parameter should really be passed by
				856	value to the function. The attribute implies that a hidden copy of the
				857	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]	858	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]	859	pointer arguments. It is generally used to pass structs and arrays by
				860	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]	861
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	862	<dt><tt>sret</tt></dt>
Duncan Sands	616cc03	2008-02-18 04:19:38 +0000	[diff] [blame]	863	<dd>This indicates that the pointer parameter specifies the address of a
				864	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]	865	Loads and stores to the structure are assumed not to trap.
Duncan Sands	616cc03	2008-02-18 04:19:38 +0000	[diff] [blame]	866	May only be applied to the first parameter.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	867
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	868	<dt><tt>noalias</tt></dt>
Owen Anderson	c4fc4cd	2008-02-18 04:09:01 +0000	[diff] [blame]	869	<dd>This indicates that the parameter does not alias any global or any other
				870	parameter. The caller is responsible for ensuring that this is the case,
				871	usually by placing the value in a stack allocation.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	872
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	873	<dt><tt>noreturn</tt></dt>
				874	<dd>This function attribute indicates that the function never returns. This
				875	indicates to LLVM that every call to this function should be treated as if
				876	an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	877
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	878	<dt><tt>nounwind</tt></dt>
Duncan Sands	ef0e9e4	2008-03-17 12:17:41 +0000	[diff] [blame]	879	<dd>This function attribute indicates that no exceptions unwind out of the
				880	function. Usually this is because the function makes no use of exceptions,
				881	but it may also be that the function catches any exceptions thrown when
				882	executing it.</dd>
				883
Duncan Sands	4ee4681	2007-07-27 19:57:41 +0000	[diff] [blame]	884	<dt><tt>nest</tt></dt>
Duncan Sands	f1a7d4c	2008-07-08 09:27:25 +0000	[diff] [blame]	885	<dd>This indicates that the pointer parameter can be excised using the
Duncan Sands	4ee4681	2007-07-27 19:57:41 +0000	[diff] [blame]	886	<a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sands	13e13f8	2007-11-22 20:23:04 +0000	[diff] [blame]	887	<dt><tt>readonly</tt></dt>
Duncan Sands	d69c0e6	2007-11-14 21:14:02 +0000	[diff] [blame]	888	<dd>This function attribute indicates that the function has no side-effects
Duncan Sands	13e13f8	2007-11-22 20:23:04 +0000	[diff] [blame]	889	except for producing a return value or throwing an exception. The value
				890	returned must only depend on the function arguments and/or global variables.
				891	It may use values obtained by dereferencing pointers.</dd>
				892	<dt><tt>readnone</tt></dt>
				893	<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]	894	function, but in addition it is not allowed to dereference any pointer arguments
				895	or global variables.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	896	</dl>
				897
				898	</div>
				899
				900	<!-- ======================================================================= -->
				901	<div class="doc_subsection">
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	902	<a name="gc">Garbage Collector Names</a>
				903	</div>
				904
				905	<div class="doc_text">
				906	<p>Each function may specify a garbage collector name, which is simply a
				907	string.</p>
				908
				909	<div class="doc_code"><pre
				910	>define void @f() gc "name" { ...</pre></div>
				911
				912	<p>The compiler declares the supported values of <i>name</i>. Specifying a
				913	collector which will cause the compiler to alter its output in order to support
				914	the named garbage collection algorithm.</p>
				915	</div>
				916
				917	<!-- ======================================================================= -->
				918	<div class="doc_subsection">
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	919	<a name="notes">Function Notes</a>
				920	</div>
				921
				922	<div class="doc_text">
Devang Patel	25928cb	2008-09-04 23:10:26 +0000	[diff] [blame]	923	<p>The function definition may list function notes which are used by
				924	various passes.</p>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	925
				926	<div class="doc_code">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	927	<pre>
				928	define void @f() notes(inline=Always) { ... }
				929	define void @f() notes(inline=Always,opt-size) { ... }
				930	define void @f() notes(inline=Never,opt-size) { ... }
				931	define void @f() notes(opt-size) { ... }
				932	</pre>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	933	</div>
				934
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	935	<dl>
				936	<dt><tt>inline=Always</tt></dt>
				937	<dd>This note requests inliner to inline this function irrespective of inlining
				938	size threshold for this function.</dd>
				939
				940	<dt><tt>inline=Never</tt></dt>
				941	<dd>This note requests inliner to never inline this function in any situation.
				942	This note may not be used together with <tt>inline=Always</tt> note.</dd>
				943
				944	<dt><tt>opt-size</tt></dt>
				945	<dd>This note suggests optimization passes and code generator passes to make
				946	choices that help reduce code size.</dd>
				947
				948	</dl>
				949
				950	<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]	951	</div>
				952
				953	<!-- ======================================================================= -->
				954	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	955	<a name="moduleasm">Module-Level Inline Assembly</a>
				956	</div>
				957
				958	<div class="doc_text">
				959	<p>
				960	Modules may contain "module-level inline asm" blocks, which corresponds to the
				961	GCC "file scope inline asm" blocks. These blocks are internally concatenated by
				962	LLVM and treated as a single unit, but may be separated in the .ll file if
				963	desired. The syntax is very simple:
				964	</p>
				965
				966	<div class="doc_code">
				967	<pre>
				968	module asm "inline asm code goes here"
				969	module asm "more can go here"
				970	</pre>
				971	</div>
				972
				973	<p>The strings can contain any character by escaping non-printable characters.
				974	The escape sequence used is simply "\xx" where "xx" is the two digit hex code
				975	for the number.
				976	</p>
				977
				978	<p>
				979	The inline asm code is simply printed to the machine code .s file when
				980	assembly code is generated.
				981	</p>
				982	</div>
				983
				984	<!-- ======================================================================= -->
				985	<div class="doc_subsection">
				986	<a name="datalayout">Data Layout</a>
				987	</div>
				988
				989	<div class="doc_text">
				990	<p>A module may specify a target specific data layout string that specifies how
				991	data is to be laid out in memory. The syntax for the data layout is simply:</p>
				992	<pre> target datalayout = "<i>layout specification</i>"</pre>
				993	<p>The <i>layout specification</i> consists of a list of specifications
				994	separated by the minus sign character ('-'). Each specification starts with a
				995	letter and may include other information after the letter to define some
				996	aspect of the data layout. The specifications accepted are as follows: </p>
				997	<dl>
				998	<dt><tt>E</tt></dt>
				999	<dd>Specifies that the target lays out data in big-endian form. That is, the
				1000	bits with the most significance have the lowest address location.</dd>
				1001	<dt><tt>e</tt></dt>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1002	<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]	1003	the bits with the least significance have the lowest address location.</dd>
				1004	<dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1005	<dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
				1006	<i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
				1007	alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
				1008	too.</dd>
				1009	<dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1010	<dd>This specifies the alignment for an integer type of a given bit
				1011	<i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
				1012	<dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1013	<dd>This specifies the alignment for a vector type of a given bit
				1014	<i>size</i>.</dd>
				1015	<dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1016	<dd>This specifies the alignment for a floating point type of a given bit
				1017	<i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
				1018	(double).</dd>
				1019	<dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1020	<dd>This specifies the alignment for an aggregate type of a given bit
				1021	<i>size</i>.</dd>
				1022	</dl>
				1023	<p>When constructing the data layout for a given target, LLVM starts with a
				1024	default set of specifications which are then (possibly) overriden by the
				1025	specifications in the <tt>datalayout</tt> keyword. The default specifications
				1026	are given in this list:</p>
				1027	<ul>
				1028	<li><tt>E</tt> - big endian</li>
				1029	<li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
				1030	<li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
				1031	<li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
				1032	<li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
				1033	<li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1034	<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]	1035	alignment of 64-bits</li>
				1036	<li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
				1037	<li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
				1038	<li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
				1039	<li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
				1040	<li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
				1041	</ul>
Chris Lattner	6a9f3c4	2008-08-05 18:21:08 +0000	[diff] [blame]	1042	<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]	1043	following rules:
				1044	<ol>
				1045	<li>If the type sought is an exact match for one of the specifications, that
				1046	specification is used.</li>
				1047	<li>If no match is found, and the type sought is an integer type, then the
				1048	smallest integer type that is larger than the bitwidth of the sought type is
				1049	used. If none of the specifications are larger than the bitwidth then the the
				1050	largest integer type is used. For example, given the default specifications
				1051	above, the i7 type will use the alignment of i8 (next largest) while both
				1052	i65 and i256 will use the alignment of i64 (largest specified).</li>
				1053	<li>If no match is found, and the type sought is a vector type, then the
				1054	largest vector type that is smaller than the sought vector type will be used
				1055	as a fall back. This happens because <128 x double> can be implemented in
				1056	terms of 64 <2 x double>, for example.</li>
				1057	</ol>
				1058	</div>
				1059
				1060	<!-- *********************************************************************** -->
				1061	<div class="doc_section"> <a name="typesystem">Type System</a> </div>
				1062	<!-- *********************************************************************** -->
				1063
				1064	<div class="doc_text">
				1065
				1066	<p>The LLVM type system is one of the most important features of the
				1067	intermediate representation. Being typed enables a number of
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1068	optimizations to be performed on the intermediate representation directly,
				1069	without having to do
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1070	extra analyses on the side before the transformation. A strong type
				1071	system makes it easier to read the generated code and enables novel
				1072	analyses and transformations that are not feasible to perform on normal
				1073	three address code representations.</p>
				1074
				1075	</div>
				1076
				1077	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1078	<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1079	Classifications</a> </div>
				1080	<div class="doc_text">
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1081	<p>The types fall into a few useful
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1082	classifications:</p>
				1083
				1084	<table border="1" cellspacing="0" cellpadding="4">
				1085	<tbody>
				1086	<tr><th>Classification</th><th>Types</th></tr>
				1087	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1088	<td><a href="#t_integer">integer</a></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1089	<td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
				1090	</tr>
				1091	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1092	<td><a href="#t_floating">floating point</a></td>
				1093	<td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1094	</tr>
				1095	<tr>
				1096	<td><a name="t_firstclass">first class</a></td>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1097	<td><a href="#t_integer">integer</a>,
				1098	<a href="#t_floating">floating point</a>,
				1099	<a href="#t_pointer">pointer</a>,
Dan Gohman	f6237db	2008-06-18 18:42:13 +0000	[diff] [blame]	1100	<a href="#t_vector">vector</a>,
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	1101	<a href="#t_struct">structure</a>,
				1102	<a href="#t_array">array</a>,
Dan Gohman	d13951e	2008-05-23 22:50:26 +0000	[diff] [blame]	1103	<a href="#t_label">label</a>.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1104	</td>
				1105	</tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1106	<tr>
				1107	<td><a href="#t_primitive">primitive</a></td>
				1108	<td><a href="#t_label">label</a>,
				1109	<a href="#t_void">void</a>,
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1110	<a href="#t_floating">floating point</a>.</td>
				1111	</tr>
				1112	<tr>
				1113	<td><a href="#t_derived">derived</a></td>
				1114	<td><a href="#t_integer">integer</a>,
				1115	<a href="#t_array">array</a>,
				1116	<a href="#t_function">function</a>,
				1117	<a href="#t_pointer">pointer</a>,
				1118	<a href="#t_struct">structure</a>,
				1119	<a href="#t_pstruct">packed structure</a>,
				1120	<a href="#t_vector">vector</a>,
				1121	<a href="#t_opaque">opaque</a>.
				1122	</tr>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1123	</tbody>
				1124	</table>
				1125
				1126	<p>The <a href="#t_firstclass">first class</a> types are perhaps the
				1127	most important. Values of these types are the only ones which can be
				1128	produced by instructions, passed as arguments, or used as operands to
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	1129	instructions.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1130	</div>
				1131
				1132	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1133	<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1134
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1135	<div class="doc_text">
				1136	<p>The primitive types are the fundamental building blocks of the LLVM
				1137	system.</p>
				1138
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1139	</div>
				1140
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1141	<!-- _______________________________________________________________________ -->
				1142	<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
				1143
				1144	<div class="doc_text">
				1145	<table>
				1146	<tbody>
				1147	<tr><th>Type</th><th>Description</th></tr>
				1148	<tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
				1149	<tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
				1150	<tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
				1151	<tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
				1152	<tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
				1153	</tbody>
				1154	</table>
				1155	</div>
				1156
				1157	<!-- _______________________________________________________________________ -->
				1158	<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
				1159
				1160	<div class="doc_text">
				1161	<h5>Overview:</h5>
				1162	<p>The void type does not represent any value and has no size.</p>
				1163
				1164	<h5>Syntax:</h5>
				1165
				1166	<pre>
				1167	void
				1168	</pre>
				1169	</div>
				1170
				1171	<!-- _______________________________________________________________________ -->
				1172	<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
				1173
				1174	<div class="doc_text">
				1175	<h5>Overview:</h5>
				1176	<p>The label type represents code labels.</p>
				1177
				1178	<h5>Syntax:</h5>
				1179
				1180	<pre>
				1181	label
				1182	</pre>
				1183	</div>
				1184
				1185
				1186	<!-- ======================================================================= -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1187	<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
				1188
				1189	<div class="doc_text">
				1190
				1191	<p>The real power in LLVM comes from the derived types in the system.
				1192	This is what allows a programmer to represent arrays, functions,
				1193	pointers, and other useful types. Note that these derived types may be
				1194	recursive: For example, it is possible to have a two dimensional array.</p>
				1195
				1196	</div>
				1197
				1198	<!-- _______________________________________________________________________ -->
				1199	<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
				1200
				1201	<div class="doc_text">
				1202
				1203	<h5>Overview:</h5>
				1204	<p>The integer type is a very simple derived type that simply specifies an
				1205	arbitrary bit width for the integer type desired. Any bit width from 1 bit to
				1206	2^23-1 (about 8 million) can be specified.</p>
				1207
				1208	<h5>Syntax:</h5>
				1209
				1210	<pre>
				1211	iN
				1212	</pre>
				1213
				1214	<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
				1215	value.</p>
				1216
				1217	<h5>Examples:</h5>
				1218	<table class="layout">
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	1219	<tbody>
				1220	<tr>
				1221	<td><tt>i1</tt></td>
				1222	<td>a single-bit integer.</td>
				1223	</tr><tr>
				1224	<td><tt>i32</tt></td>
				1225	<td>a 32-bit integer.</td>
				1226	</tr><tr>
				1227	<td><tt>i1942652</tt></td>
				1228	<td>a really big integer of over 1 million bits.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1229	</tr>
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	1230	</tbody>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1231	</table>
				1232	</div>
				1233
				1234	<!-- _______________________________________________________________________ -->
				1235	<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
				1236
				1237	<div class="doc_text">
				1238
				1239	<h5>Overview:</h5>
				1240
				1241	<p>The array type is a very simple derived type that arranges elements
				1242	sequentially in memory. The array type requires a size (number of
				1243	elements) and an underlying data type.</p>
				1244
				1245	<h5>Syntax:</h5>
				1246
				1247	<pre>
				1248	[<# elements> x <elementtype>]
				1249	</pre>
				1250
				1251	<p>The number of elements is a constant integer value; elementtype may
				1252	be any type with a size.</p>
				1253
				1254	<h5>Examples:</h5>
				1255	<table class="layout">
				1256	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1257	<td class="left"><tt>[40 x i32]</tt></td>
				1258	<td class="left">Array of 40 32-bit integer values.</td>
				1259	</tr>
				1260	<tr class="layout">
				1261	<td class="left"><tt>[41 x i32]</tt></td>
				1262	<td class="left">Array of 41 32-bit integer values.</td>
				1263	</tr>
				1264	<tr class="layout">
				1265	<td class="left"><tt>[4 x i8]</tt></td>
				1266	<td class="left">Array of 4 8-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1267	</tr>
				1268	</table>
				1269	<p>Here are some examples of multidimensional arrays:</p>
				1270	<table class="layout">
				1271	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1272	<td class="left"><tt>[3 x [4 x i32]]</tt></td>
				1273	<td class="left">3x4 array of 32-bit integer values.</td>
				1274	</tr>
				1275	<tr class="layout">
				1276	<td class="left"><tt>[12 x [10 x float]]</tt></td>
				1277	<td class="left">12x10 array of single precision floating point values.</td>
				1278	</tr>
				1279	<tr class="layout">
				1280	<td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
				1281	<td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1282	</tr>
				1283	</table>
				1284
				1285	<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
				1286	length array. Normally, accesses past the end of an array are undefined in
				1287	LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
				1288	As a special case, however, zero length arrays are recognized to be variable
				1289	length. This allows implementation of 'pascal style arrays' with the LLVM
				1290	type "{ i32, [0 x float]}", for example.</p>
				1291
				1292	</div>
				1293
				1294	<!-- _______________________________________________________________________ -->
				1295	<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
				1296	<div class="doc_text">
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	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1299
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1300	<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]	1301	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]	1302	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]	1303	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]	1304	class types, and the struct must have at least one element.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1305
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1306	<h5>Syntax:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1307
				1308	<pre>
				1309	<returntype list> (<parameter list>)
				1310	</pre>
				1311
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1312	<p>...where '<tt><parameter list></tt>' is a comma-separated list of type
				1313	specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
				1314	which indicates that the function takes a variable number of arguments.
				1315	Variable argument functions can access their arguments with the <a
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1316	href="#int_varargs">variable argument handling intrinsic</a> functions.
				1317	'<tt><returntype list></tt>' is a comma-separated list of
				1318	<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1319
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1320	<h5>Examples:</h5>
				1321	<table class="layout">
				1322	<tr class="layout">
				1323	<td class="left"><tt>i32 (i32)</tt></td>
				1324	<td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
				1325	</td>
				1326	</tr><tr class="layout">
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	1327	<td class="left"><tt>float (i16 signext, i32 )
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1328	</tt></td>
				1329	<td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
				1330	an <tt>i16</tt> that should be sign extended and a
				1331	<a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
				1332	<tt>float</tt>.
				1333	</td>
				1334	</tr><tr class="layout">
				1335	<td class="left"><tt>i32 (i8*, ...)</tt></td>
				1336	<td class="left">A vararg function that takes at least one
				1337	<a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
				1338	which returns an integer. This is the signature for <tt>printf</tt> in
				1339	LLVM.
				1340	</td>
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1341	</tr><tr class="layout">
				1342	<td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel	6dddba2	2008-03-24 18:10:52 +0000	[diff] [blame]	1343	<td class="left">A function taking an <tt>i32></tt>, returning two
				1344	<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]	1345	</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1346	</tr>
				1347	</table>
				1348
				1349	</div>
				1350	<!-- _______________________________________________________________________ -->
				1351	<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
				1352	<div class="doc_text">
				1353	<h5>Overview:</h5>
				1354	<p>The structure type is used to represent a collection of data members
				1355	together in memory. The packing of the field types is defined to match
				1356	the ABI of the underlying processor. The elements of a structure may
				1357	be any type that has a size.</p>
				1358	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
				1359	and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
				1360	field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
				1361	instruction.</p>
				1362	<h5>Syntax:</h5>
				1363	<pre> { <type list> }<br></pre>
				1364	<h5>Examples:</h5>
				1365	<table class="layout">
				1366	<tr class="layout">
				1367	<td class="left"><tt>{ i32, i32, i32 }</tt></td>
				1368	<td class="left">A triple of three <tt>i32</tt> values</td>
				1369	</tr><tr class="layout">
				1370	<td class="left"><tt>{ float, i32 (i32) * }</tt></td>
				1371	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1372	second element is a <a href="#t_pointer">pointer</a> to a
				1373	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1374	an <tt>i32</tt>.</td>
				1375	</tr>
				1376	</table>
				1377	</div>
				1378
				1379	<!-- _______________________________________________________________________ -->
				1380	<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
				1381	</div>
				1382	<div class="doc_text">
				1383	<h5>Overview:</h5>
				1384	<p>The packed structure type is used to represent a collection of data members
				1385	together in memory. There is no padding between fields. Further, the alignment
				1386	of a packed structure is 1 byte. The elements of a packed structure may
				1387	be any type that has a size.</p>
				1388	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
				1389	and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
				1390	field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
				1391	instruction.</p>
				1392	<h5>Syntax:</h5>
				1393	<pre> < { <type list> } > <br></pre>
				1394	<h5>Examples:</h5>
				1395	<table class="layout">
				1396	<tr class="layout">
				1397	<td class="left"><tt>< { i32, i32, i32 } ></tt></td>
				1398	<td class="left">A triple of three <tt>i32</tt> values</td>
				1399	</tr><tr class="layout">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1400	<td class="left">
				1401	<tt>< { float, i32 (i32)* } ></tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1402	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1403	second element is a <a href="#t_pointer">pointer</a> to a
				1404	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1405	an <tt>i32</tt>.</td>
				1406	</tr>
				1407	</table>
				1408	</div>
				1409
				1410	<!-- _______________________________________________________________________ -->
				1411	<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
				1412	<div class="doc_text">
				1413	<h5>Overview:</h5>
				1414	<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	1415	reference to another object, which must live in memory. Pointer types may have
				1416	an optional address space attribute defining the target-specific numbered
				1417	address space where the pointed-to object resides. The default address space is
				1418	zero.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1419	<h5>Syntax:</h5>
				1420	<pre> <type> *<br></pre>
				1421	<h5>Examples:</h5>
				1422	<table class="layout">
				1423	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1424	<td class="left"><tt>[4x i32]*</tt></td>
				1425	<td class="left">A <a href="#t_pointer">pointer</a> to <a
				1426	href="#t_array">array</a> of four <tt>i32</tt> values.</td>
				1427	</tr>
				1428	<tr class="layout">
				1429	<td class="left"><tt>i32 (i32 ) </tt></td>
				1430	<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]	1431	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]	1432	<tt>i32</tt>.</td>
				1433	</tr>
				1434	<tr class="layout">
				1435	<td class="left"><tt>i32 addrspace(5)*</tt></td>
				1436	<td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
				1437	that resides in address space #5.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1438	</tr>
				1439	</table>
				1440	</div>
				1441
				1442	<!-- _______________________________________________________________________ -->
				1443	<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
				1444	<div class="doc_text">
				1445
				1446	<h5>Overview:</h5>
				1447
				1448	<p>A vector type is a simple derived type that represents a vector
				1449	of elements. Vector types are used when multiple primitive data
				1450	are operated in parallel using a single instruction (SIMD).
				1451	A vector type requires a size (number of
				1452	elements) and an underlying primitive data type. Vectors must have a power
				1453	of two length (1, 2, 4, 8, 16 ...). Vector types are
				1454	considered <a href="#t_firstclass">first class</a>.</p>
				1455
				1456	<h5>Syntax:</h5>
				1457
				1458	<pre>
				1459	< <# elements> x <elementtype> >
				1460	</pre>
				1461
				1462	<p>The number of elements is a constant integer value; elementtype may
				1463	be any integer or floating point type.</p>
				1464
				1465	<h5>Examples:</h5>
				1466
				1467	<table class="layout">
				1468	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1469	<td class="left"><tt><4 x i32></tt></td>
				1470	<td class="left">Vector of 4 32-bit integer values.</td>
				1471	</tr>
				1472	<tr class="layout">
				1473	<td class="left"><tt><8 x float></tt></td>
				1474	<td class="left">Vector of 8 32-bit floating-point values.</td>
				1475	</tr>
				1476	<tr class="layout">
				1477	<td class="left"><tt><2 x i64></tt></td>
				1478	<td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1479	</tr>
				1480	</table>
				1481	</div>
				1482
				1483	<!-- _______________________________________________________________________ -->
				1484	<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
				1485	<div class="doc_text">
				1486
				1487	<h5>Overview:</h5>
				1488
				1489	<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]	1490	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]	1491	In LLVM, opaque types can eventually be resolved to any type (not just a
				1492	structure type).</p>
				1493
				1494	<h5>Syntax:</h5>
				1495
				1496	<pre>
				1497	opaque
				1498	</pre>
				1499
				1500	<h5>Examples:</h5>
				1501
				1502	<table class="layout">
				1503	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1504	<td class="left"><tt>opaque</tt></td>
				1505	<td class="left">An opaque type.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1506	</tr>
				1507	</table>
				1508	</div>
				1509
				1510
				1511	<!-- *********************************************************************** -->
				1512	<div class="doc_section"> <a name="constants">Constants</a> </div>
				1513	<!-- *********************************************************************** -->
				1514
				1515	<div class="doc_text">
				1516
				1517	<p>LLVM has several different basic types of constants. This section describes
				1518	them all and their syntax.</p>
				1519
				1520	</div>
				1521
				1522	<!-- ======================================================================= -->
				1523	<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
				1524
				1525	<div class="doc_text">
				1526
				1527	<dl>
				1528	<dt><b>Boolean constants</b></dt>
				1529
				1530	<dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
				1531	constants of the <tt><a href="#t_primitive">i1</a></tt> type.
				1532	</dd>
				1533
				1534	<dt><b>Integer constants</b></dt>
				1535
				1536	<dd>Standard integers (such as '4') are constants of the <a
				1537	href="#t_integer">integer</a> type. Negative numbers may be used with
				1538	integer types.
				1539	</dd>
				1540
				1541	<dt><b>Floating point constants</b></dt>
				1542
				1543	<dd>Floating point constants use standard decimal notation (e.g. 123.421),
				1544	exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	1545	notation (see below). The assembler requires the exact decimal value of
				1546	a floating-point constant. For example, the assembler accepts 1.25 but
				1547	rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
				1548	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]	1549
				1550	<dt><b>Null pointer constants</b></dt>
				1551
				1552	<dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
				1553	and must be of <a href="#t_pointer">pointer type</a>.</dd>
				1554
				1555	</dl>
				1556
				1557	<p>The one non-intuitive notation for constants is the optional hexadecimal form
				1558	of floating point constants. For example, the form '<tt>double
				1559	0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
				1560	4.5e+15</tt>'. The only time hexadecimal floating point constants are required
				1561	(and the only time that they are generated by the disassembler) is when a
				1562	floating point constant must be emitted but it cannot be represented as a
				1563	decimal floating point number. For example, NaN's, infinities, and other
				1564	special values are represented in their IEEE hexadecimal format so that
				1565	assembly and disassembly do not cause any bits to change in the constants.</p>
				1566
				1567	</div>
				1568
				1569	<!-- ======================================================================= -->
				1570	<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
				1571	</div>
				1572
				1573	<div class="doc_text">
				1574	<p>Aggregate constants arise from aggregation of simple constants
				1575	and smaller aggregate constants.</p>
				1576
				1577	<dl>
				1578	<dt><b>Structure constants</b></dt>
				1579
				1580	<dd>Structure constants are represented with notation similar to structure
				1581	type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner	6c8de96	2007-12-25 20:34:52 +0000	[diff] [blame]	1582	(<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
				1583	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]	1584	must have <a href="#t_struct">structure type</a>, and the number and
				1585	types of elements must match those specified by the type.
				1586	</dd>
				1587
				1588	<dt><b>Array constants</b></dt>
				1589
				1590	<dd>Array constants are represented with notation similar to array type
				1591	definitions (a comma separated list of elements, surrounded by square brackets
				1592	(<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
				1593	constants must have <a href="#t_array">array type</a>, and the number and
				1594	types of elements must match those specified by the type.
				1595	</dd>
				1596
				1597	<dt><b>Vector constants</b></dt>
				1598
				1599	<dd>Vector constants are represented with notation similar to vector type
				1600	definitions (a comma separated list of elements, surrounded by
				1601	less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32 42,
				1602	i32 11, i32 74, i32 100 ></tt>". Vector constants must have <a
				1603	href="#t_vector">vector type</a>, and the number and types of elements must
				1604	match those specified by the type.
				1605	</dd>
				1606
				1607	<dt><b>Zero initialization</b></dt>
				1608
				1609	<dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
				1610	value to zero of <em>any</em> type, including scalar and aggregate types.
				1611	This is often used to avoid having to print large zero initializers (e.g. for
				1612	large arrays) and is always exactly equivalent to using explicit zero
				1613	initializers.
				1614	</dd>
				1615	</dl>
				1616
				1617	</div>
				1618
				1619	<!-- ======================================================================= -->
				1620	<div class="doc_subsection">
				1621	<a name="globalconstants">Global Variable and Function Addresses</a>
				1622	</div>
				1623
				1624	<div class="doc_text">
				1625
				1626	<p>The addresses of <a href="#globalvars">global variables</a> and <a
				1627	href="#functionstructure">functions</a> are always implicitly valid (link-time)
				1628	constants. These constants are explicitly referenced when the <a
				1629	href="#identifiers">identifier for the global</a> is used and always have <a
				1630	href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
				1631	file:</p>
				1632
				1633	<div class="doc_code">
				1634	<pre>
				1635	@X = global i32 17
				1636	@Y = global i32 42
				1637	@Z = global [2 x i32] [ i32 @X, i32* @Y ]
				1638	</pre>
				1639	</div>
				1640
				1641	</div>
				1642
				1643	<!-- ======================================================================= -->
				1644	<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
				1645	<div class="doc_text">
				1646	<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
				1647	no specific value. Undefined values may be of any type and be used anywhere
				1648	a constant is permitted.</p>
				1649
				1650	<p>Undefined values indicate to the compiler that the program is well defined
				1651	no matter what value is used, giving the compiler more freedom to optimize.
				1652	</p>
				1653	</div>
				1654
				1655	<!-- ======================================================================= -->
				1656	<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
				1657	</div>
				1658
				1659	<div class="doc_text">
				1660
				1661	<p>Constant expressions are used to allow expressions involving other constants
				1662	to be used as constants. Constant expressions may be of any <a
				1663	href="#t_firstclass">first class</a> type and may involve any LLVM operation
				1664	that does not have side effects (e.g. load and call are not supported). The
				1665	following is the syntax for constant expressions:</p>
				1666
				1667	<dl>
				1668	<dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
				1669	<dd>Truncate a constant to another type. The bit size of CST must be larger
				1670	than the bit size of TYPE. Both types must be integers.</dd>
				1671
				1672	<dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
				1673	<dd>Zero extend a constant to another type. The bit size of CST must be
				1674	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1675
				1676	<dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
				1677	<dd>Sign extend a constant to another type. The bit size of CST must be
				1678	smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
				1679
				1680	<dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
				1681	<dd>Truncate a floating point constant to another floating point type. The
				1682	size of CST must be larger than the size of TYPE. Both types must be
				1683	floating point.</dd>
				1684
				1685	<dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
				1686	<dd>Floating point extend a constant to another type. The size of CST must be
				1687	smaller or equal to the size of TYPE. Both types must be floating point.</dd>
				1688
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	1689	<dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1690	<dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1691	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1692	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1693	of the same number of elements. If the value won't fit in the integer type,
				1694	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1695
				1696	<dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
				1697	<dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1698	constant. TYPE must be a scalar or vector integer type. CST must be of scalar
				1699	or vector floating point type. Both CST and TYPE must be scalars, or vectors
				1700	of the same number of elements. If the value won't fit in the integer type,
				1701	the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1702
				1703	<dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
				1704	<dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1705	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1706	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1707	of the same number of elements. If the value won't fit in the floating point
				1708	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1709
				1710	<dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
				1711	<dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	1712	constant. TYPE must be a scalar or vector floating point type. CST must be of
				1713	scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
				1714	of the same number of elements. If the value won't fit in the floating point
				1715	type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1716
				1717	<dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
				1718	<dd>Convert a pointer typed constant to the corresponding integer constant
				1719	TYPE must be an integer type. CST must be of pointer type. The CST value is
				1720	zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
				1721
				1722	<dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
				1723	<dd>Convert a integer constant to a pointer constant. TYPE must be a
				1724	pointer type. CST must be of integer type. The CST value is zero extended,
				1725	truncated, or unchanged to make it fit in a pointer size. This one is
				1726	<i>really</i> dangerous!</dd>
				1727
				1728	<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
				1729	<dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
				1730	identical (same number of bits). The conversion is done as if the CST value
				1731	was stored to memory and read back as TYPE. In other words, no bits change
				1732	with this operator, just the type. This can be used for conversion of
				1733	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]	1734	pointers it is only valid to cast to another pointer type. It is not valid
				1735	to bitcast to or from an aggregate type.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1736	</dd>
				1737
				1738	<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
				1739
				1740	<dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
				1741	constants. As with the <a href="#i_getelementptr">getelementptr</a>
				1742	instruction, the index list may have zero or more indexes, which are required
				1743	to make sense for the type of "CSTPTR".</dd>
				1744
				1745	<dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
				1746
				1747	<dd>Perform the <a href="#i_select">select operation</a> on
				1748	constants.</dd>
				1749
				1750	<dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
				1751	<dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
				1752
				1753	<dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1754	<dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
				1755
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	1756	<dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
				1757	<dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
				1758
				1759	<dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
				1760	<dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
				1761
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1762	<dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
				1763
				1764	<dd>Perform the <a href="#i_extractelement">extractelement
				1765	operation</a> on constants.
				1766
				1767	<dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
				1768
				1769	<dd>Perform the <a href="#i_insertelement">insertelement
				1770	operation</a> on constants.</dd>
				1771
				1772
				1773	<dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
				1774
				1775	<dd>Perform the <a href="#i_shufflevector">shufflevector
				1776	operation</a> on constants.</dd>
				1777
				1778	<dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
				1779
				1780	<dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
				1781	be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
				1782	binary</a> operations. The constraints on operands are the same as those for
				1783	the corresponding instruction (e.g. no bitwise operations on floating point
				1784	values are allowed).</dd>
				1785	</dl>
				1786	</div>
				1787
				1788	<!-- *********************************************************************** -->
				1789	<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
				1790	<!-- *********************************************************************** -->
				1791
				1792	<!-- ======================================================================= -->
				1793	<div class="doc_subsection">
				1794	<a name="inlineasm">Inline Assembler Expressions</a>
				1795	</div>
				1796
				1797	<div class="doc_text">
				1798
				1799	<p>
				1800	LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
				1801	Module-Level Inline Assembly</a>) through the use of a special value. This
				1802	value represents the inline assembler as a string (containing the instructions
				1803	to emit), a list of operand constraints (stored as a string), and a flag that
				1804	indicates whether or not the inline asm expression has side effects. An example
				1805	inline assembler expression is:
				1806	</p>
				1807
				1808	<div class="doc_code">
				1809	<pre>
				1810	i32 (i32) asm "bswap $0", "=r,r"
				1811	</pre>
				1812	</div>
				1813
				1814	<p>
				1815	Inline assembler expressions may <b>only</b> be used as the callee operand of
				1816	a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
				1817	</p>
				1818
				1819	<div class="doc_code">
				1820	<pre>
				1821	%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
				1822	</pre>
				1823	</div>
				1824
				1825	<p>
				1826	Inline asms with side effects not visible in the constraint list must be marked
				1827	as having side effects. This is done through the use of the
				1828	'<tt>sideeffect</tt>' keyword, like so:
				1829	</p>
				1830
				1831	<div class="doc_code">
				1832	<pre>
				1833	call void asm sideeffect "eieio", ""()
				1834	</pre>
				1835	</div>
				1836
				1837	<p>TODO: The format of the asm and constraints string still need to be
				1838	documented here. Constraints on what can be done (e.g. duplication, moving, etc
				1839	need to be documented).
				1840	</p>
				1841
				1842	</div>
				1843
				1844	<!-- *********************************************************************** -->
				1845	<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
				1846	<!-- *********************************************************************** -->
				1847
				1848	<div class="doc_text">
				1849
				1850	<p>The LLVM instruction set consists of several different
				1851	classifications of instructions: <a href="#terminators">terminator
				1852	instructions</a>, <a href="#binaryops">binary instructions</a>,
				1853	<a href="#bitwiseops">bitwise binary instructions</a>, <a
				1854	href="#memoryops">memory instructions</a>, and <a href="#otherops">other
				1855	instructions</a>.</p>
				1856
				1857	</div>
				1858
				1859	<!-- ======================================================================= -->
				1860	<div class="doc_subsection"> <a name="terminators">Terminator
				1861	Instructions</a> </div>
				1862
				1863	<div class="doc_text">
				1864
				1865	<p>As mentioned <a href="#functionstructure">previously</a>, every
				1866	basic block in a program ends with a "Terminator" instruction, which
				1867	indicates which block should be executed after the current block is
				1868	finished. These terminator instructions typically yield a '<tt>void</tt>'
				1869	value: they produce control flow, not values (the one exception being
				1870	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
				1871	<p>There are six different terminator instructions: the '<a
				1872	href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
				1873	instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
				1874	the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
				1875	href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
				1876	href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
				1877
				1878	</div>
				1879
				1880	<!-- _______________________________________________________________________ -->
				1881	<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
				1882	Instruction</a> </div>
				1883	<div class="doc_text">
				1884	<h5>Syntax:</h5>
				1885	<pre> ret <type> <value> <i>; Return a value from a non-void function</i>
				1886	ret void <i>; Return from void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1887	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]	1888	</pre>
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	<h5>Overview:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1891
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1892	<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
				1893	value) from a function back to the caller.</p>
				1894	<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]	1895	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]	1896	control flow to occur.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1897
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1898	<h5>Arguments:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1899
				1900	<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
				1901	The type of each return value must be a '<a href="#t_firstclass">first
				1902	class</a>' type. Note that a function is not <a href="#wellformed">well
				1903	formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
				1904	function that returns values that do not match the return type of the
				1905	function.</p>
				1906
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1907	<h5>Semantics:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1908
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1909	<p>When the '<tt>ret</tt>' instruction is executed, control flow
				1910	returns back to the calling function's context. If the caller is a "<a
				1911	href="#i_call"><tt>call</tt></a>" instruction, execution continues at
				1912	the instruction after the call. If the caller was an "<a
				1913	href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
				1914	at the beginning of the "normal" destination block. If the instruction
				1915	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]	1916	return value. If the instruction returns multiple values then these
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	1917	values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
				1918	</a>' instruction.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1919
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1920	<h5>Example:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1921
				1922	<pre>
				1923	ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1924	ret void <i>; Return from a void function</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1925	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]	1926	</pre>
				1927	</div>
				1928	<!-- _______________________________________________________________________ -->
				1929	<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
				1930	<div class="doc_text">
				1931	<h5>Syntax:</h5>
				1932	<pre> br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
				1933	</pre>
				1934	<h5>Overview:</h5>
				1935	<p>The '<tt>br</tt>' instruction is used to cause control flow to
				1936	transfer to a different basic block in the current function. There are
				1937	two forms of this instruction, corresponding to a conditional branch
				1938	and an unconditional branch.</p>
				1939	<h5>Arguments:</h5>
				1940	<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
				1941	single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
				1942	unconditional form of the '<tt>br</tt>' instruction takes a single
				1943	'<tt>label</tt>' value as a target.</p>
				1944	<h5>Semantics:</h5>
				1945	<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
				1946	argument is evaluated. If the value is <tt>true</tt>, control flows
				1947	to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
				1948	control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
				1949	<h5>Example:</h5>
				1950	<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
				1951	href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
				1952	</div>
				1953	<!-- _______________________________________________________________________ -->
				1954	<div class="doc_subsubsection">
				1955	<a name="i_switch">'<tt>switch</tt>' Instruction</a>
				1956	</div>
				1957
				1958	<div class="doc_text">
				1959	<h5>Syntax:</h5>
				1960
				1961	<pre>
				1962	switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
				1963	</pre>
				1964
				1965	<h5>Overview:</h5>
				1966
				1967	<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
				1968	several different places. It is a generalization of the '<tt>br</tt>'
				1969	instruction, allowing a branch to occur to one of many possible
				1970	destinations.</p>
				1971
				1972
				1973	<h5>Arguments:</h5>
				1974
				1975	<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
				1976	comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
				1977	an array of pairs of comparison value constants and '<tt>label</tt>'s. The
				1978	table is not allowed to contain duplicate constant entries.</p>
				1979
				1980	<h5>Semantics:</h5>
				1981
				1982	<p>The <tt>switch</tt> instruction specifies a table of values and
				1983	destinations. When the '<tt>switch</tt>' instruction is executed, this
				1984	table is searched for the given value. If the value is found, control flow is
				1985	transfered to the corresponding destination; otherwise, control flow is
				1986	transfered to the default destination.</p>
				1987
				1988	<h5>Implementation:</h5>
				1989
				1990	<p>Depending on properties of the target machine and the particular
				1991	<tt>switch</tt> instruction, this instruction may be code generated in different
				1992	ways. For example, it could be generated as a series of chained conditional
				1993	branches or with a lookup table.</p>
				1994
				1995	<h5>Example:</h5>
				1996
				1997	<pre>
				1998	<i>; Emulate a conditional br instruction</i>
				1999	%Val = <a href="#i_zext">zext</a> i1 %value to i32
				2000	switch i32 %Val, label %truedest [i32 0, label %falsedest ]
				2001
				2002	<i>; Emulate an unconditional br instruction</i>
				2003	switch i32 0, label %dest [ ]
				2004
				2005	<i>; Implement a jump table:</i>
				2006	switch i32 %val, label %otherwise [ i32 0, label %onzero
				2007	i32 1, label %onone
				2008	i32 2, label %ontwo ]
				2009	</pre>
				2010	</div>
				2011
				2012	<!-- _______________________________________________________________________ -->
				2013	<div class="doc_subsubsection">
				2014	<a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
				2015	</div>
				2016
				2017	<div class="doc_text">
				2018
				2019	<h5>Syntax:</h5>
				2020
				2021	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2022	<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]	2023	to label <normal label> unwind label <exception label>
				2024	</pre>
				2025
				2026	<h5>Overview:</h5>
				2027
				2028	<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
				2029	function, with the possibility of control flow transfer to either the
				2030	'<tt>normal</tt>' label or the
				2031	'<tt>exception</tt>' label. If the callee function returns with the
				2032	"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
				2033	"normal" label. If the callee (or any indirect callees) returns with the "<a
				2034	href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	2035	continued at the dynamically nearest "exception" label. If the callee function
Devang Patel	ec8a5b0	2008-03-11 05:51:59 +0000	[diff] [blame]	2036	returns multiple values then individual return values are only accessible through
				2037	a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2038
				2039	<h5>Arguments:</h5>
				2040
				2041	<p>This instruction requires several arguments:</p>
				2042
				2043	<ol>
				2044	<li>
				2045	The optional "cconv" marker indicates which <a href="#callingconv">calling
				2046	convention</a> the call should use. If none is specified, the call defaults
				2047	to using C calling conventions.
				2048	</li>
				2049	<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
				2050	function value being invoked. In most cases, this is a direct function
				2051	invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
				2052	an arbitrary pointer to function value.
				2053	</li>
				2054
				2055	<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
				2056	function to be invoked. </li>
				2057
				2058	<li>'<tt>function args</tt>': argument list whose types match the function
				2059	signature argument types. If the function signature indicates the function
				2060	accepts a variable number of arguments, the extra arguments can be
				2061	specified. </li>
				2062
				2063	<li>'<tt>normal label</tt>': the label reached when the called function
				2064	executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
				2065
				2066	<li>'<tt>exception label</tt>': the label reached when a callee returns with
				2067	the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
				2068
				2069	</ol>
				2070
				2071	<h5>Semantics:</h5>
				2072
				2073	<p>This instruction is designed to operate as a standard '<tt><a
				2074	href="#i_call">call</a></tt>' instruction in most regards. The primary
				2075	difference is that it establishes an association with a label, which is used by
				2076	the runtime library to unwind the stack.</p>
				2077
				2078	<p>This instruction is used in languages with destructors to ensure that proper
				2079	cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
				2080	exception. Additionally, this is important for implementation of
				2081	'<tt>catch</tt>' clauses in high-level languages that support them.</p>
				2082
				2083	<h5>Example:</h5>
				2084	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2085	%retval = invoke i32 @Test(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>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2087	%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]	2088	unwind label %TestCleanup <i>; {i32}:retval set</i>
				2089	</pre>
				2090	</div>
				2091
				2092
				2093	<!-- _______________________________________________________________________ -->
				2094
				2095	<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
				2096	Instruction</a> </div>
				2097
				2098	<div class="doc_text">
				2099
				2100	<h5>Syntax:</h5>
				2101	<pre>
				2102	unwind
				2103	</pre>
				2104
				2105	<h5>Overview:</h5>
				2106
				2107	<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
				2108	at the first callee in the dynamic call stack which used an <a
				2109	href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
				2110	primarily used to implement exception handling.</p>
				2111
				2112	<h5>Semantics:</h5>
				2113
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	2114	<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]	2115	immediately halt. The dynamic call stack is then searched for the first <a
				2116	href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
				2117	execution continues at the "exceptional" destination block specified by the
				2118	<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
				2119	dynamic call chain, undefined behavior results.</p>
				2120	</div>
				2121
				2122	<!-- _______________________________________________________________________ -->
				2123
				2124	<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
				2125	Instruction</a> </div>
				2126
				2127	<div class="doc_text">
				2128
				2129	<h5>Syntax:</h5>
				2130	<pre>
				2131	unreachable
				2132	</pre>
				2133
				2134	<h5>Overview:</h5>
				2135
				2136	<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
				2137	instruction is used to inform the optimizer that a particular portion of the
				2138	code is not reachable. This can be used to indicate that the code after a
				2139	no-return function cannot be reached, and other facts.</p>
				2140
				2141	<h5>Semantics:</h5>
				2142
				2143	<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
				2144	</div>
				2145
				2146
				2147
				2148	<!-- ======================================================================= -->
				2149	<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
				2150	<div class="doc_text">
				2151	<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]	2152	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]	2153	produce a single value. The operands might represent
				2154	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]	2155	The result value has the same type as its operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2156	<p>There are several different binary operators:</p>
				2157	</div>
				2158	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2159	<div class="doc_subsubsection">
				2160	<a name="i_add">'<tt>add</tt>' Instruction</a>
				2161	</div>
				2162
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2163	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2164
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2165	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2166
				2167	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2168	<result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2169	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2170
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2171	<h5>Overview:</h5>
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	<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]	2174
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2175	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2176
				2177	<p>The two arguments to the '<tt>add</tt>' instruction must be <a
				2178	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
				2179	<a href="#t_vector">vector</a> values. Both arguments must have identical
				2180	types.</p>
				2181
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2182	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2183
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2184	<p>The value produced is the integer or floating point sum of the two
				2185	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2186
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2187	<p>If an integer sum has unsigned overflow, the result returned is the
				2188	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2189	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2190
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2191	<p>Because LLVM integers use a two's complement representation, this
				2192	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2193
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2194	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2195
				2196	<pre>
				2197	<result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2198	</pre>
				2199	</div>
				2200	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2201	<div class="doc_subsubsection">
				2202	<a name="i_sub">'<tt>sub</tt>' Instruction</a>
				2203	</div>
				2204
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2205	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2206
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2207	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2208
				2209	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2210	<result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2211	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2214
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2215	<p>The '<tt>sub</tt>' instruction returns the difference of its two
				2216	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2217
				2218	<p>Note that the '<tt>sub</tt>' instruction is used to represent the
				2219	'<tt>neg</tt>' instruction present in most other intermediate
				2220	representations.</p>
				2221
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2222	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2223
				2224	<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
				2225	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2226	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2227	types.</p>
				2228
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2229	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2230
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2231	<p>The value produced is the integer or floating point difference of
				2232	the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2233
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2234	<p>If an integer difference has unsigned overflow, the result returned is the
				2235	mathematical result modulo 2<sup>n</sup>, where n is the bit width of
				2236	the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2237
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2238	<p>Because LLVM integers use a two's complement representation, this
				2239	instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2240
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2241	<h5>Example:</h5>
				2242	<pre>
				2243	<result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
				2244	<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
				2245	</pre>
				2246	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2247
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2248	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2249	<div class="doc_subsubsection">
				2250	<a name="i_mul">'<tt>mul</tt>' Instruction</a>
				2251	</div>
				2252
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2253	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2254
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2255	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2256	<pre> <result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2257	</pre>
				2258	<h5>Overview:</h5>
				2259	<p>The '<tt>mul</tt>' instruction returns the product of its two
				2260	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2261
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2262	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2263
				2264	<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
				2265	href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
				2266	or <a href="#t_vector">vector</a> values. Both arguments must have identical
				2267	types.</p>
				2268
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2269	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2270
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2271	<p>The value produced is the integer or floating point product of the
				2272	two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2273
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2274	<p>If the result of an integer multiplication has unsigned overflow,
				2275	the result returned is the mathematical result modulo
				2276	2<sup>n</sup>, where n is the bit width of the result.</p>
				2277	<p>Because LLVM integers use a two's complement representation, and the
				2278	result is the same width as the operands, this instruction returns the
				2279	correct result for both signed and unsigned integers. If a full product
				2280	(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
				2281	should be sign-extended or zero-extended as appropriate to the
				2282	width of the full product.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2283	<h5>Example:</h5>
				2284	<pre> <result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
				2285	</pre>
				2286	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2287
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2288	<!-- _______________________________________________________________________ -->
				2289	<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
				2290	</a></div>
				2291	<div class="doc_text">
				2292	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2293	<pre> <result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2294	</pre>
				2295	<h5>Overview:</h5>
				2296	<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
				2297	operands.</p>
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	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2300
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2301	<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2302	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2303	values. Both arguments must have identical types.</p>
				2304
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2305	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2306
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2307	<p>The value produced is the unsigned integer quotient of the two operands.</p>
				2308	<p>Note that unsigned integer division and signed integer division are distinct
				2309	operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
				2310	<p>Division by zero leads to undefined behavior.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2311	<h5>Example:</h5>
				2312	<pre> <result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2313	</pre>
				2314	</div>
				2315	<!-- _______________________________________________________________________ -->
				2316	<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
				2317	</a> </div>
				2318	<div class="doc_text">
				2319	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2320	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2321	<result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2322	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2325
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2326	<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
				2327	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2328
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2329	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2330
				2331	<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
				2332	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2333	values. Both arguments must have identical types.</p>
				2334
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2335	<h5>Semantics:</h5>
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2336	<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]	2337	<p>Note that signed integer division and unsigned integer division are distinct
				2338	operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
				2339	<p>Division by zero leads to undefined behavior. Overflow also leads to
				2340	undefined behavior; this is a rare case, but can occur, for example,
				2341	by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2342	<h5>Example:</h5>
				2343	<pre> <result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
				2344	</pre>
				2345	</div>
				2346	<!-- _______________________________________________________________________ -->
				2347	<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
				2348	Instruction</a> </div>
				2349	<div class="doc_text">
				2350	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2351	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2352	<result> = fdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2353	</pre>
				2354	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2355
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2356	<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
				2357	operands.</p>
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	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2360
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2361	<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2362	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2363	of floating point values. Both arguments must have identical types.</p>
				2364
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2365	<h5>Semantics:</h5>
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	<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]	2368
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2369	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2370
				2371	<pre>
				2372	<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]	2373	</pre>
				2374	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2375
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2376	<!-- _______________________________________________________________________ -->
				2377	<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
				2378	</div>
				2379	<div class="doc_text">
				2380	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2381	<pre> <result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2382	</pre>
				2383	<h5>Overview:</h5>
				2384	<p>The '<tt>urem</tt>' instruction returns the remainder from the
				2385	unsigned division of its two arguments.</p>
				2386	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2387	<p>The two arguments to the '<tt>urem</tt>' instruction must be
				2388	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2389	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2390	<h5>Semantics:</h5>
				2391	<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]	2392	This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2393	<p>Note that unsigned integer remainder and signed integer remainder are
				2394	distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
				2395	<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]	2396	<h5>Example:</h5>
				2397	<pre> <result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2398	</pre>
				2399
				2400	</div>
				2401	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2402	<div class="doc_subsubsection">
				2403	<a name="i_srem">'<tt>srem</tt>' Instruction</a>
				2404	</div>
				2405
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2406	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2407
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2408	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2409
				2410	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2411	<result> = srem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2412	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2415
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2416	<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman	3e3fd8c	2007-11-05 23:35:22 +0000	[diff] [blame]	2417	signed division of its two operands. This instruction can also take
				2418	<a href="#t_vector">vector</a> versions of the values in which case
				2419	the elements must be integers.</p>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	2420
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2421	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2422
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2423	<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2424	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2425	values. Both arguments must have identical types.</p>
				2426
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2427	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2428
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2429	<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]	2430	has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
				2431	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]	2432	a value. For more information about the difference, see <a
				2433	href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
				2434	Math Forum</a>. For a table of how this is implemented in various languages,
				2435	please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
				2436	Wikipedia: modulo operation</a>.</p>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2437	<p>Note that signed integer remainder and unsigned integer remainder are
				2438	distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
				2439	<p>Taking the remainder of a division by zero leads to undefined behavior.
				2440	Overflow also leads to undefined behavior; this is a rare case, but can occur,
				2441	for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
				2442	(The remainder doesn't actually overflow, but this rule lets srem be
				2443	implemented using instructions that return both the result of the division
				2444	and the remainder.)</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2445	<h5>Example:</h5>
				2446	<pre> <result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
				2447	</pre>
				2448
				2449	</div>
				2450	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2451	<div class="doc_subsubsection">
				2452	<a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
				2453
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2454	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2455
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2456	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2457	<pre> <result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2458	</pre>
				2459	<h5>Overview:</h5>
				2460	<p>The '<tt>frem</tt>' instruction returns the remainder from the
				2461	division of its two operands.</p>
				2462	<h5>Arguments:</h5>
				2463	<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2464	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
				2465	of floating point values. Both arguments must have identical types.</p>
				2466
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2467	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2468
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2469	<p>This instruction returns the <i>remainder</i> of a division.
				2470	The remainder has the same sign as the dividend.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2471
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2472	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2473
				2474	<pre>
				2475	<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]	2476	</pre>
				2477	</div>
				2478
				2479	<!-- ======================================================================= -->
				2480	<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
				2481	Operations</a> </div>
				2482	<div class="doc_text">
				2483	<p>Bitwise binary operators are used to do various forms of
				2484	bit-twiddling in a program. They are generally very efficient
				2485	instructions and can commonly be strength reduced from other
Chris Lattner	dc15b1d	2008-04-01 18:45:27 +0000	[diff] [blame]	2486	instructions. They require two operands of the same type, execute an operation on them,
				2487	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]	2488	</div>
				2489
				2490	<!-- _______________________________________________________________________ -->
				2491	<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
				2492	Instruction</a> </div>
				2493	<div class="doc_text">
				2494	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2495	<pre> <result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2496	</pre>
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	<h5>Overview:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2499
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2500	<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
				2501	the left a specified number of bits.</p>
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	<h5>Arguments:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2504
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2505	<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]	2506	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]	2507	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2508
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2509	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2510
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2511	<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
				2512	where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
				2513	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]	2514
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2515	<h5>Example:</h5><pre>
				2516	<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
				2517	<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
				2518	<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2519	<result> = shl i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2520	</pre>
				2521	</div>
				2522	<!-- _______________________________________________________________________ -->
				2523	<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
				2524	Instruction</a> </div>
				2525	<div class="doc_text">
				2526	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2527	<pre> <result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2528	</pre>
				2529
				2530	<h5>Overview:</h5>
				2531	<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
				2532	operand shifted to the right a specified number of bits with zero fill.</p>
				2533
				2534	<h5>Arguments:</h5>
				2535	<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]	2536	<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]	2537	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2538
				2539	<h5>Semantics:</h5>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2540
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2541	<p>This instruction always performs a logical shift right operation. The most
				2542	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]	2543	shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
				2544	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]	2545
				2546	<h5>Example:</h5>
				2547	<pre>
				2548	<result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2549	<result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2550	<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2551	<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2552	<result> = lshr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2553	</pre>
				2554	</div>
				2555
				2556	<!-- _______________________________________________________________________ -->
				2557	<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
				2558	Instruction</a> </div>
				2559	<div class="doc_text">
				2560
				2561	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2562	<pre> <result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2563	</pre>
				2564
				2565	<h5>Overview:</h5>
				2566	<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
				2567	operand shifted to the right a specified number of bits with sign extension.</p>
				2568
				2569	<h5>Arguments:</h5>
				2570	<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]	2571	<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]	2572	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2573
				2574	<h5>Semantics:</h5>
				2575	<p>This instruction always performs an arithmetic shift right operation,
				2576	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]	2577	of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
				2578	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]	2579	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2580
				2581	<h5>Example:</h5>
				2582	<pre>
				2583	<result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
				2584	<result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
				2585	<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
				2586	<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	2587	<result> = ashr i32 1, 32 <i>; undefined</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2588	</pre>
				2589	</div>
				2590
				2591	<!-- _______________________________________________________________________ -->
				2592	<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
				2593	Instruction</a> </div>
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	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2596
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2597	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2598
				2599	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2600	<result> = and <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2601	</pre>
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	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2604
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2605	<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
				2606	its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2607
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2608	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2609
				2610	<p>The two arguments to the '<tt>and</tt>' instruction must be
				2611	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2612	values. Both arguments must have identical types.</p>
				2613
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2614	<h5>Semantics:</h5>
				2615	<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
				2616	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2617	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2618	<table border="1" cellspacing="0" cellpadding="4">
				2619	<tbody>
				2620	<tr>
				2621	<td>In0</td>
				2622	<td>In1</td>
				2623	<td>Out</td>
				2624	</tr>
				2625	<tr>
				2626	<td>0</td>
				2627	<td>0</td>
				2628	<td>0</td>
				2629	</tr>
				2630	<tr>
				2631	<td>0</td>
				2632	<td>1</td>
				2633	<td>0</td>
				2634	</tr>
				2635	<tr>
				2636	<td>1</td>
				2637	<td>0</td>
				2638	<td>0</td>
				2639	</tr>
				2640	<tr>
				2641	<td>1</td>
				2642	<td>1</td>
				2643	<td>1</td>
				2644	</tr>
				2645	</tbody>
				2646	</table>
				2647	</div>
				2648	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2649	<pre>
				2650	<result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2651	<result> = and i32 15, 40 <i>; yields {i32}:result = 8</i>
				2652	<result> = and i32 4, 8 <i>; yields {i32}:result = 0</i>
				2653	</pre>
				2654	</div>
				2655	<!-- _______________________________________________________________________ -->
				2656	<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
				2657	<div class="doc_text">
				2658	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2659	<pre> <result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2660	</pre>
				2661	<h5>Overview:</h5>
				2662	<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
				2663	or of its two operands.</p>
				2664	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2665
				2666	<p>The two arguments to the '<tt>or</tt>' instruction must be
				2667	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2668	values. Both arguments must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2669	<h5>Semantics:</h5>
				2670	<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
				2671	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2672	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2673	<table border="1" cellspacing="0" cellpadding="4">
				2674	<tbody>
				2675	<tr>
				2676	<td>In0</td>
				2677	<td>In1</td>
				2678	<td>Out</td>
				2679	</tr>
				2680	<tr>
				2681	<td>0</td>
				2682	<td>0</td>
				2683	<td>0</td>
				2684	</tr>
				2685	<tr>
				2686	<td>0</td>
				2687	<td>1</td>
				2688	<td>1</td>
				2689	</tr>
				2690	<tr>
				2691	<td>1</td>
				2692	<td>0</td>
				2693	<td>1</td>
				2694	</tr>
				2695	<tr>
				2696	<td>1</td>
				2697	<td>1</td>
				2698	<td>1</td>
				2699	</tr>
				2700	</tbody>
				2701	</table>
				2702	</div>
				2703	<h5>Example:</h5>
				2704	<pre> <result> = or i32 4, %var <i>; yields {i32}:result = 4 \| %var</i>
				2705	<result> = or i32 15, 40 <i>; yields {i32}:result = 47</i>
				2706	<result> = or i32 4, 8 <i>; yields {i32}:result = 12</i>
				2707	</pre>
				2708	</div>
				2709	<!-- _______________________________________________________________________ -->
				2710	<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
				2711	Instruction</a> </div>
				2712	<div class="doc_text">
				2713	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2714	<pre> <result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2715	</pre>
				2716	<h5>Overview:</h5>
				2717	<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
				2718	or of its two operands. The <tt>xor</tt> is used to implement the
				2719	"one's complement" operation, which is the "~" operator in C.</p>
				2720	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2721	<p>The two arguments to the '<tt>xor</tt>' instruction must be
				2722	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2723	values. Both arguments must have identical types.</p>
				2724
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2725	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2726
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2727	<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
				2728	<p> </p>
Bill Wendling	1e19eac	2008-09-07 10:29:20 +0000	[diff] [blame]	2729	<div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2730	<table border="1" cellspacing="0" cellpadding="4">
				2731	<tbody>
				2732	<tr>
				2733	<td>In0</td>
				2734	<td>In1</td>
				2735	<td>Out</td>
				2736	</tr>
				2737	<tr>
				2738	<td>0</td>
				2739	<td>0</td>
				2740	<td>0</td>
				2741	</tr>
				2742	<tr>
				2743	<td>0</td>
				2744	<td>1</td>
				2745	<td>1</td>
				2746	</tr>
				2747	<tr>
				2748	<td>1</td>
				2749	<td>0</td>
				2750	<td>1</td>
				2751	</tr>
				2752	<tr>
				2753	<td>1</td>
				2754	<td>1</td>
				2755	<td>0</td>
				2756	</tr>
				2757	</tbody>
				2758	</table>
				2759	</div>
				2760	<p> </p>
				2761	<h5>Example:</h5>
				2762	<pre> <result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
				2763	<result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
				2764	<result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
				2765	<result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
				2766	</pre>
				2767	</div>
				2768
				2769	<!-- ======================================================================= -->
				2770	<div class="doc_subsection">
				2771	<a name="vectorops">Vector Operations</a>
				2772	</div>
				2773
				2774	<div class="doc_text">
				2775
				2776	<p>LLVM supports several instructions to represent vector operations in a
				2777	target-independent manner. These instructions cover the element-access and
				2778	vector-specific operations needed to process vectors effectively. While LLVM
				2779	does directly support these vector operations, many sophisticated algorithms
				2780	will want to use target-specific intrinsics to take full advantage of a specific
				2781	target.</p>
				2782
				2783	</div>
				2784
				2785	<!-- _______________________________________________________________________ -->
				2786	<div class="doc_subsubsection">
				2787	<a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
				2788	</div>
				2789
				2790	<div class="doc_text">
				2791
				2792	<h5>Syntax:</h5>
				2793
				2794	<pre>
				2795	<result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
				2796	</pre>
				2797
				2798	<h5>Overview:</h5>
				2799
				2800	<p>
				2801	The '<tt>extractelement</tt>' instruction extracts a single scalar
				2802	element from a vector at a specified index.
				2803	</p>
				2804
				2805
				2806	<h5>Arguments:</h5>
				2807
				2808	<p>
				2809	The first operand of an '<tt>extractelement</tt>' instruction is a
				2810	value of <a href="#t_vector">vector</a> type. The second operand is
				2811	an index indicating the position from which to extract the element.
				2812	The index may be a variable.</p>
				2813
				2814	<h5>Semantics:</h5>
				2815
				2816	<p>
				2817	The result is a scalar of the same type as the element type of
				2818	<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
				2819	<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
				2820	results are undefined.
				2821	</p>
				2822
				2823	<h5>Example:</h5>
				2824
				2825	<pre>
				2826	%result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
				2827	</pre>
				2828	</div>
				2829
				2830
				2831	<!-- _______________________________________________________________________ -->
				2832	<div class="doc_subsubsection">
				2833	<a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
				2834	</div>
				2835
				2836	<div class="doc_text">
				2837
				2838	<h5>Syntax:</h5>
				2839
				2840	<pre>
Dan Gohman	bcc3c50	2008-05-12 23:38:42 +0000	[diff] [blame]	2841	<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]	2842	</pre>
				2843
				2844	<h5>Overview:</h5>
				2845
				2846	<p>
				2847	The '<tt>insertelement</tt>' instruction inserts a scalar
				2848	element into a vector at a specified index.
				2849	</p>
				2850
				2851
				2852	<h5>Arguments:</h5>
				2853
				2854	<p>
				2855	The first operand of an '<tt>insertelement</tt>' instruction is a
				2856	value of <a href="#t_vector">vector</a> type. The second operand is a
				2857	scalar value whose type must equal the element type of the first
				2858	operand. The third operand is an index indicating the position at
				2859	which to insert the value. The index may be a variable.</p>
				2860
				2861	<h5>Semantics:</h5>
				2862
				2863	<p>
				2864	The result is a vector of the same type as <tt>val</tt>. Its
				2865	element values are those of <tt>val</tt> except at position
				2866	<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
				2867	exceeds the length of <tt>val</tt>, the results are undefined.
				2868	</p>
				2869
				2870	<h5>Example:</h5>
				2871
				2872	<pre>
				2873	%result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
				2874	</pre>
				2875	</div>
				2876
				2877	<!-- _______________________________________________________________________ -->
				2878	<div class="doc_subsubsection">
				2879	<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
				2880	</div>
				2881
				2882	<div class="doc_text">
				2883
				2884	<h5>Syntax:</h5>
				2885
				2886	<pre>
				2887	<result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x i32> <mask> <i>; yields <n x <ty>></i>
				2888	</pre>
				2889
				2890	<h5>Overview:</h5>
				2891
				2892	<p>
				2893	The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
				2894	from two input vectors, returning a vector of the same type.
				2895	</p>
				2896
				2897	<h5>Arguments:</h5>
				2898
				2899	<p>
				2900	The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
				2901	with types that match each other and types that match the result of the
				2902	instruction. The third argument is a shuffle mask, which has the same number
				2903	of elements as the other vector type, but whose element type is always 'i32'.
				2904	</p>
				2905
				2906	<p>
				2907	The shuffle mask operand is required to be a constant vector with either
				2908	constant integer or undef values.
				2909	</p>
				2910
				2911	<h5>Semantics:</h5>
				2912
				2913	<p>
				2914	The elements of the two input vectors are numbered from left to right across
				2915	both of the vectors. The shuffle mask operand specifies, for each element of
				2916	the result vector, which element of the two input registers the result element
				2917	gets. The element selector may be undef (meaning "don't care") and the second
				2918	operand may be undef if performing a shuffle from only one vector.
				2919	</p>
				2920
				2921	<h5>Example:</h5>
				2922
				2923	<pre>
				2924	%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
				2925	<4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
				2926	%result = shufflevector <4 x i32> %v1, <4 x i32> undef,
				2927	<4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
				2928	</pre>
				2929	</div>
				2930
				2931
				2932	<!-- ======================================================================= -->
				2933	<div class="doc_subsection">
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2934	<a name="aggregateops">Aggregate Operations</a>
				2935	</div>
				2936
				2937	<div class="doc_text">
				2938
				2939	<p>LLVM supports several instructions for working with aggregate values.
				2940	</p>
				2941
				2942	</div>
				2943
				2944	<!-- _______________________________________________________________________ -->
				2945	<div class="doc_subsubsection">
				2946	<a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
				2947	</div>
				2948
				2949	<div class="doc_text">
				2950
				2951	<h5>Syntax:</h5>
				2952
				2953	<pre>
				2954	<result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
				2955	</pre>
				2956
				2957	<h5>Overview:</h5>
				2958
				2959	<p>
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	2960	The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
				2961	or array element from an aggregate value.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2962	</p>
				2963
				2964
				2965	<h5>Arguments:</h5>
				2966
				2967	<p>
				2968	The first operand of an '<tt>extractvalue</tt>' instruction is a
				2969	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]	2970	type. The operands are constant indices to specify which value to extract
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2971	in a similar manner as indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2972	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				2973	</p>
				2974
				2975	<h5>Semantics:</h5>
				2976
				2977	<p>
				2978	The result is the value at the position in the aggregate specified by
				2979	the index operands.
				2980	</p>
				2981
				2982	<h5>Example:</h5>
				2983
				2984	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	2985	%result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	2986	</pre>
				2987	</div>
				2988
				2989
				2990	<!-- _______________________________________________________________________ -->
				2991	<div class="doc_subsubsection">
				2992	<a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
				2993	</div>
				2994
				2995	<div class="doc_text">
				2996
				2997	<h5>Syntax:</h5>
				2998
				2999	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3000	<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]	3001	</pre>
				3002
				3003	<h5>Overview:</h5>
				3004
				3005	<p>
				3006	The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman	6c6dea0	2008-05-13 18:16:06 +0000	[diff] [blame]	3007	into a struct field or array element in an aggregate.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3008	</p>
				3009
				3010
				3011	<h5>Arguments:</h5>
				3012
				3013	<p>
				3014	The first operand of an '<tt>insertvalue</tt>' instruction is a
				3015	value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
				3016	The second operand is a first-class value to insert.
Dan Gohman	4f29e42	2008-05-23 21:53:15 +0000	[diff] [blame]	3017	The following operands are constant indices
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3018	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]	3019	indices in a
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3020	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
				3021	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]	3022	by the indices.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3023
				3024	<h5>Semantics:</h5>
				3025
				3026	<p>
				3027	The result is an aggregate of the same type as <tt>val</tt>. Its
				3028	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]	3029	specified by the indices is that of <tt>elt</tt>.
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3030	</p>
				3031
				3032	<h5>Example:</h5>
				3033
				3034	<pre>
Dan Gohman	b1aab4e	2008-06-23 15:26:37 +0000	[diff] [blame]	3035	%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]	3036	</pre>
				3037	</div>
				3038
				3039
				3040	<!-- ======================================================================= -->
				3041	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3042	<a name="memoryops">Memory Access and Addressing Operations</a>
				3043	</div>
				3044
				3045	<div class="doc_text">
				3046
				3047	<p>A key design point of an SSA-based representation is how it
				3048	represents memory. In LLVM, no memory locations are in SSA form, which
				3049	makes things very simple. This section describes how to read, write,
				3050	allocate, and free memory in LLVM.</p>
				3051
				3052	</div>
				3053
				3054	<!-- _______________________________________________________________________ -->
				3055	<div class="doc_subsubsection">
				3056	<a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
				3057	</div>
				3058
				3059	<div class="doc_text">
				3060
				3061	<h5>Syntax:</h5>
				3062
				3063	<pre>
				3064	<result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3065	</pre>
				3066
				3067	<h5>Overview:</h5>
				3068
				3069	<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3070	heap and returns a pointer to it. The object is always allocated in the generic
				3071	address space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3072
				3073	<h5>Arguments:</h5>
				3074
				3075	<p>The '<tt>malloc</tt>' instruction allocates
				3076	<tt>sizeof(<type>)*NumElements</tt>
				3077	bytes of memory from the operating system and returns a pointer of the
				3078	appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3079	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3080	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]	3081	be aligned to at least that boundary. If not specified, or if zero, the target can
				3082	choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3083
				3084	<p>'<tt>type</tt>' must be a sized type.</p>
				3085
				3086	<h5>Semantics:</h5>
				3087
				3088	<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3089	a pointer is returned. The result of a zero byte allocattion is undefined. The
				3090	result is null if there is insufficient memory available.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3091
				3092	<h5>Example:</h5>
				3093
				3094	<pre>
				3095	%array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
				3096
				3097	%size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
				3098	%array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
				3099	%array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
				3100	%array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
				3101	%array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
				3102	</pre>
				3103	</div>
				3104
				3105	<!-- _______________________________________________________________________ -->
				3106	<div class="doc_subsubsection">
				3107	<a name="i_free">'<tt>free</tt>' Instruction</a>
				3108	</div>
				3109
				3110	<div class="doc_text">
				3111
				3112	<h5>Syntax:</h5>
				3113
				3114	<pre>
				3115	free <type> <value> <i>; yields {void}</i>
				3116	</pre>
				3117
				3118	<h5>Overview:</h5>
				3119
				3120	<p>The '<tt>free</tt>' instruction returns memory back to the unused
				3121	memory heap to be reallocated in the future.</p>
				3122
				3123	<h5>Arguments:</h5>
				3124
				3125	<p>'<tt>value</tt>' shall be a pointer value that points to a value
				3126	that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
				3127	instruction.</p>
				3128
				3129	<h5>Semantics:</h5>
				3130
				3131	<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]	3132	after this instruction executes. If the pointer is null, the operation
				3133	is a noop.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3134
				3135	<h5>Example:</h5>
				3136
				3137	<pre>
				3138	%array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
				3139	free [4 x i8]* %array
				3140	</pre>
				3141	</div>
				3142
				3143	<!-- _______________________________________________________________________ -->
				3144	<div class="doc_subsubsection">
				3145	<a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
				3146	</div>
				3147
				3148	<div class="doc_text">
				3149
				3150	<h5>Syntax:</h5>
				3151
				3152	<pre>
				3153	<result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3154	</pre>
				3155
				3156	<h5>Overview:</h5>
				3157
				3158	<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
				3159	currently executing function, to be automatically released when this function
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	3160	returns to its caller. The object is always allocated in the generic address
				3161	space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3162
				3163	<h5>Arguments:</h5>
				3164
				3165	<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
				3166	bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif	5082cf4	2008-02-09 22:24:34 +0000	[diff] [blame]	3167	appropriate type to the program. If "NumElements" is specified, it is the
				3168	number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3169	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]	3170	to be aligned to at least that boundary. If not specified, or if zero, the target
				3171	can choose to align the allocation on any convenient boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3172
				3173	<p>'<tt>type</tt>' may be any sized type.</p>
				3174
				3175	<h5>Semantics:</h5>
				3176
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	3177	<p>Memory is allocated; a pointer is returned. The operation is undefiend if
				3178	there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3179	memory is automatically released when the function returns. The '<tt>alloca</tt>'
				3180	instruction is commonly used to represent automatic variables that must
				3181	have an address available. When the function returns (either with the <tt><a
				3182	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]	3183	instructions), the memory is reclaimed. Allocating zero bytes
				3184	is legal, but the result is undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3185
				3186	<h5>Example:</h5>
				3187
				3188	<pre>
				3189	%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
				3190	%ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
				3191	%ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
				3192	%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
				3193	</pre>
				3194	</div>
				3195
				3196	<!-- _______________________________________________________________________ -->
				3197	<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
				3198	Instruction</a> </div>
				3199	<div class="doc_text">
				3200	<h5>Syntax:</h5>
				3201	<pre> <result> = load <ty>* <pointer>[, align <alignment>]<br> <result> = volatile load <ty>* <pointer>[, align <alignment>]<br></pre>
				3202	<h5>Overview:</h5>
				3203	<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
				3204	<h5>Arguments:</h5>
				3205	<p>The argument to the '<tt>load</tt>' instruction specifies the memory
				3206	address from which to load. The pointer must point to a <a
				3207	href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
				3208	marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
				3209	the number or order of execution of this <tt>load</tt> with other
				3210	volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
				3211	instructions. </p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3212	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3213	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3214	(that is, the alignment of the memory address). A value of 0 or an
				3215	omitted "align" argument means that the operation has the preferential
				3216	alignment for the target. It is the responsibility of the code emitter
				3217	to ensure that the alignment information is correct. Overestimating
				3218	the alignment results in an undefined behavior. Underestimating the
				3219	alignment may produce less efficient code. An alignment of 1 is always
				3220	safe.
				3221	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3222	<h5>Semantics:</h5>
				3223	<p>The location of memory pointed to is loaded.</p>
				3224	<h5>Examples:</h5>
				3225	<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
				3226	<a
				3227	href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
				3228	%val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
				3229	</pre>
				3230	</div>
				3231	<!-- _______________________________________________________________________ -->
				3232	<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
				3233	Instruction</a> </div>
				3234	<div class="doc_text">
				3235	<h5>Syntax:</h5>
				3236	<pre> store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3237	volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3238	</pre>
				3239	<h5>Overview:</h5>
				3240	<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
				3241	<h5>Arguments:</h5>
				3242	<p>There are two arguments to the '<tt>store</tt>' instruction: a value
				3243	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]	3244	operand must be a pointer to the <a href="#t_firstclass">first class</a> type
				3245	of the '<tt><value></tt>'
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3246	operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
				3247	optimizer is not allowed to modify the number or order of execution of
				3248	this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
				3249	href="#i_store">store</a></tt> instructions.</p>
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3250	<p>
Chris Lattner	10368b6	2008-04-02 00:38:26 +0000	[diff] [blame]	3251	The optional constant "align" argument specifies the alignment of the operation
Chris Lattner	21003c8	2008-01-06 21:04:43 +0000	[diff] [blame]	3252	(that is, the alignment of the memory address). A value of 0 or an
				3253	omitted "align" argument means that the operation has the preferential
				3254	alignment for the target. It is the responsibility of the code emitter
				3255	to ensure that the alignment information is correct. Overestimating
				3256	the alignment results in an undefined behavior. Underestimating the
				3257	alignment may produce less efficient code. An alignment of 1 is always
				3258	safe.
				3259	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3260	<h5>Semantics:</h5>
				3261	<p>The contents of memory are updated to contain '<tt><value></tt>'
				3262	at the location specified by the '<tt><pointer></tt>' operand.</p>
				3263	<h5>Example:</h5>
				3264	<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]	3265	store i32 3, i32* %ptr <i>; yields {void}</i>
				3266	%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]	3267	</pre>
				3268	</div>
				3269
				3270	<!-- _______________________________________________________________________ -->
				3271	<div class="doc_subsubsection">
				3272	<a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
				3273	</div>
				3274
				3275	<div class="doc_text">
				3276	<h5>Syntax:</h5>
				3277	<pre>
				3278	<result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}*
				3279	</pre>
				3280
				3281	<h5>Overview:</h5>
				3282
				3283	<p>
				3284	The '<tt>getelementptr</tt>' instruction is used to get the address of a
				3285	subelement of an aggregate data structure.</p>
				3286
				3287	<h5>Arguments:</h5>
				3288
				3289	<p>This instruction takes a list of integer operands that indicate what
				3290	elements of the aggregate object to index to. The actual types of the arguments
				3291	provided depend on the type of the first pointer argument. The
				3292	'<tt>getelementptr</tt>' instruction is used to index down through the type
				3293	levels of a structure or to a specific index in an array. When indexing into a
				3294	structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	3295	into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
				3296	values will be sign extended to 64-bits if required.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3297
				3298	<p>For example, let's consider a C code fragment and how it gets
				3299	compiled to LLVM:</p>
				3300
				3301	<div class="doc_code">
				3302	<pre>
				3303	struct RT {
				3304	char A;
				3305	int B[10][20];
				3306	char C;
				3307	};
				3308	struct ST {
				3309	int X;
				3310	double Y;
				3311	struct RT Z;
				3312	};
				3313
				3314	int foo(struct ST s) {
				3315	return &s[1].Z.B[5][13];
				3316	}
				3317	</pre>
				3318	</div>
				3319
				3320	<p>The LLVM code generated by the GCC frontend is:</p>
				3321
				3322	<div class="doc_code">
				3323	<pre>
				3324	%RT = type { i8 , [10 x [20 x i32]], i8 }
				3325	%ST = type { i32, double, %RT }
				3326
				3327	define i32* %foo(%ST* %s) {
				3328	entry:
				3329	%reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
				3330	ret i32* %reg
				3331	}
				3332	</pre>
				3333	</div>
				3334
				3335	<h5>Semantics:</h5>
				3336
				3337	<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
				3338	on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
				3339	and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
				3340	<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]	3341	to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
				3342	structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3343
				3344	<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
				3345	type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
				3346	}</tt>' type, a structure. The second index indexes into the third element of
				3347	the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
				3348	i8 }</tt>' type, another structure. The third index indexes into the second
				3349	element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
				3350	array. The two dimensions of the array are subscripted into, yielding an
				3351	'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
				3352	to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
				3353
				3354	<p>Note that it is perfectly legal to index partially through a
				3355	structure, returning a pointer to an inner element. Because of this,
				3356	the LLVM code for the given testcase is equivalent to:</p>
				3357
				3358	<pre>
				3359	define i32* %foo(%ST* %s) {
				3360	%t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
				3361	%t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
				3362	%t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
				3363	%t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
				3364	%t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
				3365	ret i32* %t5
				3366	}
				3367	</pre>
				3368
				3369	<p>Note that it is undefined to access an array out of bounds: array and
				3370	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]	3371	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]	3372	defined to be accessible as variable length arrays, which requires access
				3373	beyond the zero'th element.</p>
				3374
				3375	<p>The getelementptr instruction is often confusing. For some more insight
				3376	into how it works, see <a href="GetElementPtr.html">the getelementptr
				3377	FAQ</a>.</p>
				3378
				3379	<h5>Example:</h5>
				3380
				3381	<pre>
				3382	<i>; yields [12 x i8]*:aptr</i>
				3383	%aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
				3384	</pre>
				3385	</div>
				3386
				3387	<!-- ======================================================================= -->
				3388	<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
				3389	</div>
				3390	<div class="doc_text">
				3391	<p>The instructions in this category are the conversion instructions (casting)
				3392	which all take a single operand and a type. They perform various bit conversions
				3393	on the operand.</p>
				3394	</div>
				3395
				3396	<!-- _______________________________________________________________________ -->
				3397	<div class="doc_subsubsection">
				3398	<a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
				3399	</div>
				3400	<div class="doc_text">
				3401
				3402	<h5>Syntax:</h5>
				3403	<pre>
				3404	<result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3405	</pre>
				3406
				3407	<h5>Overview:</h5>
				3408	<p>
				3409	The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
				3410	</p>
				3411
				3412	<h5>Arguments:</h5>
				3413	<p>
				3414	The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
				3415	be an <a href="#t_integer">integer</a> type, and a type that specifies the size
				3416	and type of the result, which must be an <a href="#t_integer">integer</a>
				3417	type. The bit size of <tt>value</tt> must be larger than the bit size of
				3418	<tt>ty2</tt>. Equal sized types are not allowed.</p>
				3419
				3420	<h5>Semantics:</h5>
				3421	<p>
				3422	The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
				3423	and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
				3424	larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
				3425	It will always truncate bits.</p>
				3426
				3427	<h5>Example:</h5>
				3428	<pre>
				3429	%X = trunc i32 257 to i8 <i>; yields i8:1</i>
				3430	%Y = trunc i32 123 to i1 <i>; yields i1:true</i>
				3431	%Y = trunc i32 122 to i1 <i>; yields i1:false</i>
				3432	</pre>
				3433	</div>
				3434
				3435	<!-- _______________________________________________________________________ -->
				3436	<div class="doc_subsubsection">
				3437	<a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
				3438	</div>
				3439	<div class="doc_text">
				3440
				3441	<h5>Syntax:</h5>
				3442	<pre>
				3443	<result> = zext <ty> <value> to <ty2> <i>; yields ty2</i>
				3444	</pre>
				3445
				3446	<h5>Overview:</h5>
				3447	<p>The '<tt>zext</tt>' instruction zero extends its operand to type
				3448	<tt>ty2</tt>.</p>
				3449
				3450
				3451	<h5>Arguments:</h5>
				3452	<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
				3453	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3454	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3455	<tt>value</tt> must be smaller than the bit size of the destination type,
				3456	<tt>ty2</tt>.</p>
				3457
				3458	<h5>Semantics:</h5>
				3459	<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
				3460	bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
				3461
				3462	<p>When zero extending from i1, the result will always be either 0 or 1.</p>
				3463
				3464	<h5>Example:</h5>
				3465	<pre>
				3466	%X = zext i32 257 to i64 <i>; yields i64:257</i>
				3467	%Y = zext i1 true to i32 <i>; yields i32:1</i>
				3468	</pre>
				3469	</div>
				3470
				3471	<!-- _______________________________________________________________________ -->
				3472	<div class="doc_subsubsection">
				3473	<a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
				3474	</div>
				3475	<div class="doc_text">
				3476
				3477	<h5>Syntax:</h5>
				3478	<pre>
				3479	<result> = sext <ty> <value> to <ty2> <i>; yields ty2</i>
				3480	</pre>
				3481
				3482	<h5>Overview:</h5>
				3483	<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
				3484
				3485	<h5>Arguments:</h5>
				3486	<p>
				3487	The '<tt>sext</tt>' instruction takes a value to cast, which must be of
				3488	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				3489	also be of <a href="#t_integer">integer</a> type. The bit size of the
				3490	<tt>value</tt> must be smaller than the bit size of the destination type,
				3491	<tt>ty2</tt>.</p>
				3492
				3493	<h5>Semantics:</h5>
				3494	<p>
				3495	The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
				3496	bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
				3497	the type <tt>ty2</tt>.</p>
				3498
				3499	<p>When sign extending from i1, the extension always results in -1 or 0.</p>
				3500
				3501	<h5>Example:</h5>
				3502	<pre>
				3503	%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
				3504	%Y = sext i1 true to i32 <i>; yields i32:-1</i>
				3505	</pre>
				3506	</div>
				3507
				3508	<!-- _______________________________________________________________________ -->
				3509	<div class="doc_subsubsection">
				3510	<a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
				3511	</div>
				3512
				3513	<div class="doc_text">
				3514
				3515	<h5>Syntax:</h5>
				3516
				3517	<pre>
				3518	<result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i>
				3519	</pre>
				3520
				3521	<h5>Overview:</h5>
				3522	<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
				3523	<tt>ty2</tt>.</p>
				3524
				3525
				3526	<h5>Arguments:</h5>
				3527	<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
				3528	point</a> value to cast and a <a href="#t_floating">floating point</a> type to
				3529	cast it to. The size of <tt>value</tt> must be larger than the size of
				3530	<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
				3531	<i>no-op cast</i>.</p>
				3532
				3533	<h5>Semantics:</h5>
				3534	<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
				3535	<a href="#t_floating">floating point</a> type to a smaller
				3536	<a href="#t_floating">floating point</a> type. If the value cannot fit within
				3537	the destination type, <tt>ty2</tt>, then the results are undefined.</p>
				3538
				3539	<h5>Example:</h5>
				3540	<pre>
				3541	%X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
				3542	%Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
				3543	</pre>
				3544	</div>
				3545
				3546	<!-- _______________________________________________________________________ -->
				3547	<div class="doc_subsubsection">
				3548	<a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
				3549	</div>
				3550	<div class="doc_text">
				3551
				3552	<h5>Syntax:</h5>
				3553	<pre>
				3554	<result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i>
				3555	</pre>
				3556
				3557	<h5>Overview:</h5>
				3558	<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
				3559	floating point value.</p>
				3560
				3561	<h5>Arguments:</h5>
				3562	<p>The '<tt>fpext</tt>' instruction takes a
				3563	<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
				3564	and a <a href="#t_floating">floating point</a> type to cast it to. The source
				3565	type must be smaller than the destination type.</p>
				3566
				3567	<h5>Semantics:</h5>
				3568	<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
				3569	<a href="#t_floating">floating point</a> type to a larger
				3570	<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
				3571	used to make a <i>no-op cast</i> because it always changes bits. Use
				3572	<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
				3573
				3574	<h5>Example:</h5>
				3575	<pre>
				3576	%X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
				3577	%Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
				3578	</pre>
				3579	</div>
				3580
				3581	<!-- _______________________________________________________________________ -->
				3582	<div class="doc_subsubsection">
				3583	<a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
				3584	</div>
				3585	<div class="doc_text">
				3586
				3587	<h5>Syntax:</h5>
				3588	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3589	<result> = fptoui <ty> <value> to <ty2> <i>; yields ty2</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3590	</pre>
				3591
				3592	<h5>Overview:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3593	<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]	3594	unsigned integer equivalent of type <tt>ty2</tt>.
				3595	</p>
				3596
				3597	<h5>Arguments:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3598	<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]	3599	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3600	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3601	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3602	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]	3603
				3604	<h5>Semantics:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3605	<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3606	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3607	towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
				3608	the results are undefined.</p>
				3609
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3610	<h5>Example:</h5>
				3611	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	3612	%X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3613	%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]	3614	%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]	3615	</pre>
				3616	</div>
				3617
				3618	<!-- _______________________________________________________________________ -->
				3619	<div class="doc_subsubsection">
				3620	<a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
				3621	</div>
				3622	<div class="doc_text">
				3623
				3624	<h5>Syntax:</h5>
				3625	<pre>
				3626	<result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i>
				3627	</pre>
				3628
				3629	<h5>Overview:</h5>
				3630	<p>The '<tt>fptosi</tt>' instruction converts
				3631	<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
				3632	</p>
				3633
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3634	<h5>Arguments:</h5>
				3635	<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]	3636	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				3637	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				3638	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				3639	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]	3640
				3641	<h5>Semantics:</h5>
				3642	<p>The '<tt>fptosi</tt>' instruction converts its
				3643	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				3644	towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
				3645	the results are undefined.</p>
				3646
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3647	<h5>Example:</h5>
				3648	<pre>
				3649	%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	3650	%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]	3651	%X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
				3652	</pre>
				3653	</div>
				3654
				3655	<!-- _______________________________________________________________________ -->
				3656	<div class="doc_subsubsection">
				3657	<a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
				3658	</div>
				3659	<div class="doc_text">
				3660
				3661	<h5>Syntax:</h5>
				3662	<pre>
				3663	<result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3664	</pre>
				3665
				3666	<h5>Overview:</h5>
				3667	<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
				3668	integer and converts that value to the <tt>ty2</tt> type.</p>
				3669
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3670	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3671	<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
				3672	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3673	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3674	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3675	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]	3676
				3677	<h5>Semantics:</h5>
				3678	<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
				3679	integer quantity and converts it to the corresponding floating point value. If
				3680	the value cannot fit in the floating point value, the results are undefined.</p>
				3681
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3682	<h5>Example:</h5>
				3683	<pre>
				3684	%X = uitofp i32 257 to float <i>; yields float:257.0</i>
				3685	%Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
				3686	</pre>
				3687	</div>
				3688
				3689	<!-- _______________________________________________________________________ -->
				3690	<div class="doc_subsubsection">
				3691	<a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
				3692	</div>
				3693	<div class="doc_text">
				3694
				3695	<h5>Syntax:</h5>
				3696	<pre>
				3697	<result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				3698	</pre>
				3699
				3700	<h5>Overview:</h5>
				3701	<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
				3702	integer and converts that value to the <tt>ty2</tt> type.</p>
				3703
				3704	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	3705	<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
				3706	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
				3707	to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				3708	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				3709	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]	3710
				3711	<h5>Semantics:</h5>
				3712	<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
				3713	integer quantity and converts it to the corresponding floating point value. If
				3714	the value cannot fit in the floating point value, the results are undefined.</p>
				3715
				3716	<h5>Example:</h5>
				3717	<pre>
				3718	%X = sitofp i32 257 to float <i>; yields float:257.0</i>
				3719	%Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
				3720	</pre>
				3721	</div>
				3722
				3723	<!-- _______________________________________________________________________ -->
				3724	<div class="doc_subsubsection">
				3725	<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
				3726	</div>
				3727	<div class="doc_text">
				3728
				3729	<h5>Syntax:</h5>
				3730	<pre>
				3731	<result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i>
				3732	</pre>
				3733
				3734	<h5>Overview:</h5>
				3735	<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
				3736	the integer type <tt>ty2</tt>.</p>
				3737
				3738	<h5>Arguments:</h5>
				3739	<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
				3740	must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
				3741	<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
				3742
				3743	<h5>Semantics:</h5>
				3744	<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
				3745	<tt>ty2</tt> by interpreting the pointer value as an integer and either
				3746	truncating or zero extending that value to the size of the integer type. If
				3747	<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
				3748	<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
				3749	are the same size, then nothing is done (<i>no-op cast</i>) other than a type
				3750	change.</p>
				3751
				3752	<h5>Example:</h5>
				3753	<pre>
				3754	%X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
				3755	%Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
				3756	</pre>
				3757	</div>
				3758
				3759	<!-- _______________________________________________________________________ -->
				3760	<div class="doc_subsubsection">
				3761	<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
				3762	</div>
				3763	<div class="doc_text">
				3764
				3765	<h5>Syntax:</h5>
				3766	<pre>
				3767	<result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i>
				3768	</pre>
				3769
				3770	<h5>Overview:</h5>
				3771	<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
				3772	a pointer type, <tt>ty2</tt>.</p>
				3773
				3774	<h5>Arguments:</h5>
				3775	<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
				3776	value to cast, and a type to cast it to, which must be a
				3777	<a href="#t_pointer">pointer</a> type.
				3778
				3779	<h5>Semantics:</h5>
				3780	<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
				3781	<tt>ty2</tt> by applying either a zero extension or a truncation depending on
				3782	the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
				3783	size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
				3784	the size of a pointer then a zero extension is done. If they are the same size,
				3785	nothing is done (<i>no-op cast</i>).</p>
				3786
				3787	<h5>Example:</h5>
				3788	<pre>
				3789	%X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
				3790	%X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
				3791	%Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
				3792	</pre>
				3793	</div>
				3794
				3795	<!-- _______________________________________________________________________ -->
				3796	<div class="doc_subsubsection">
				3797	<a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
				3798	</div>
				3799	<div class="doc_text">
				3800
				3801	<h5>Syntax:</h5>
				3802	<pre>
				3803	<result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i>
				3804	</pre>
				3805
				3806	<h5>Overview:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3807
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3808	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3809	<tt>ty2</tt> without changing any bits.</p>
				3810
				3811	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3812
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3813	<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]	3814	a non-aggregate first class value, and a type to cast it to, which must also be
				3815	a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
				3816	<tt>value</tt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3817	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]	3818	type is a pointer, the destination type must also be a pointer. This
				3819	instruction supports bitwise conversion of vectors to integers and to vectors
				3820	of other types (as long as they have the same size).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3821
				3822	<h5>Semantics:</h5>
				3823	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
				3824	<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
				3825	this conversion. The conversion is done as if the <tt>value</tt> had been
				3826	stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
				3827	converted to other pointer types with this instruction. To convert pointers to
				3828	other types, use the <a href="#i_inttoptr">inttoptr</a> or
				3829	<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
				3830
				3831	<h5>Example:</h5>
				3832	<pre>
				3833	%X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
				3834	%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
				3835	%Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
				3836	</pre>
				3837	</div>
				3838
				3839	<!-- ======================================================================= -->
				3840	<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
				3841	<div class="doc_text">
				3842	<p>The instructions in this category are the "miscellaneous"
				3843	instructions, which defy better classification.</p>
				3844	</div>
				3845
				3846	<!-- _______________________________________________________________________ -->
				3847	<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
				3848	</div>
				3849	<div class="doc_text">
				3850	<h5>Syntax:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3851	<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]	3852	</pre>
				3853	<h5>Overview:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3854	<p>The '<tt>icmp</tt>' instruction returns a boolean value or
				3855	a vector of boolean values based on comparison
				3856	of its two integer, integer vector, or pointer operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3857	<h5>Arguments:</h5>
				3858	<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
				3859	the condition code indicating the kind of comparison to perform. It is not
				3860	a value, just a keyword. The possible condition code are:
				3861	<ol>
				3862	<li><tt>eq</tt>: equal</li>
				3863	<li><tt>ne</tt>: not equal </li>
				3864	<li><tt>ugt</tt>: unsigned greater than</li>
				3865	<li><tt>uge</tt>: unsigned greater or equal</li>
				3866	<li><tt>ult</tt>: unsigned less than</li>
				3867	<li><tt>ule</tt>: unsigned less or equal</li>
				3868	<li><tt>sgt</tt>: signed greater than</li>
				3869	<li><tt>sge</tt>: signed greater or equal</li>
				3870	<li><tt>slt</tt>: signed less than</li>
				3871	<li><tt>sle</tt>: signed less or equal</li>
				3872	</ol>
				3873	<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]	3874	<a href="#t_pointer">pointer</a>
				3875	or integer <a href="#t_vector">vector</a> typed.
				3876	They must also be identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3877	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3878	<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]	3879	the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3880	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]	3881	<ol>
				3882	<li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
				3883	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3884	</li>
				3885	<li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
				3886	<tt>false</tt> otherwise. No sign interpretation is necessary or performed.
				3887	<li><tt>ugt</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 <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3889	<li><tt>uge</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 greater than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3891	<li><tt>ult</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 <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3893	<li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3894	<tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3895	<li><tt>sgt</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 <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3897	<li><tt>sge</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 greater than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3899	<li><tt>slt</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 <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3901	<li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3902	<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]	3903	</ol>
				3904	<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
				3905	values are compared as if they were integers.</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3906	<p>If the operands are integer vectors, then they are compared
				3907	element by element. The result is an <tt>i1</tt> vector with
				3908	the same number of elements as the values being compared.
				3909	Otherwise, the result is an <tt>i1</tt>.
				3910	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3911
				3912	<h5>Example:</h5>
				3913	<pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
				3914	<result> = icmp ne float* %X, %X <i>; yields: result=false</i>
				3915	<result> = icmp ult i16 4, 5 <i>; yields: result=true</i>
				3916	<result> = icmp sgt i16 4, 5 <i>; yields: result=false</i>
				3917	<result> = icmp ule i16 -4, 5 <i>; yields: result=false</i>
				3918	<result> = icmp sge i16 4, 5 <i>; yields: result=false</i>
				3919	</pre>
				3920	</div>
				3921
				3922	<!-- _______________________________________________________________________ -->
				3923	<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
				3924	</div>
				3925	<div class="doc_text">
				3926	<h5>Syntax:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3927	<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]	3928	</pre>
				3929	<h5>Overview:</h5>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3930	<p>The '<tt>fcmp</tt>' instruction returns a boolean value
				3931	or vector of boolean values based on comparison
				3932	of its operands.
				3933	<p>
				3934	If the operands are floating point scalars, then the result
				3935	type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
				3936	</p>
				3937	<p>If the operands are floating point vectors, then the result type
				3938	is a vector of boolean with the same number of elements as the
				3939	operands being compared.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3940	<h5>Arguments:</h5>
				3941	<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
				3942	the condition code indicating the kind of comparison to perform. It is not
				3943	a value, just a keyword. The possible condition code are:
				3944	<ol>
				3945	<li><tt>false</tt>: no comparison, always returns false</li>
				3946	<li><tt>oeq</tt>: ordered and equal</li>
				3947	<li><tt>ogt</tt>: ordered and greater than </li>
				3948	<li><tt>oge</tt>: ordered and greater than or equal</li>
				3949	<li><tt>olt</tt>: ordered and less than </li>
				3950	<li><tt>ole</tt>: ordered and less than or equal</li>
				3951	<li><tt>one</tt>: ordered and not equal</li>
				3952	<li><tt>ord</tt>: ordered (no nans)</li>
				3953	<li><tt>ueq</tt>: unordered or equal</li>
				3954	<li><tt>ugt</tt>: unordered or greater than </li>
				3955	<li><tt>uge</tt>: unordered or greater than or equal</li>
				3956	<li><tt>ult</tt>: unordered or less than </li>
				3957	<li><tt>ule</tt>: unordered or less than or equal</li>
				3958	<li><tt>une</tt>: unordered or not equal</li>
				3959	<li><tt>uno</tt>: unordered (either nans)</li>
				3960	<li><tt>true</tt>: no comparison, always returns true</li>
				3961	</ol>
				3962	<p><i>Ordered</i> means that neither operand is a QNAN while
				3963	<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	3964	<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
				3965	either a <a href="#t_floating">floating point</a> type
				3966	or a <a href="#t_vector">vector</a> of floating point type.
				3967	They must have identical types.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3968	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3969	<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]	3970	according to the condition code given as <tt>cond</tt>.
				3971	If the operands are vectors, then the vectors are compared
				3972	element by element.
				3973	Each comparison performed
				3974	always yields an <a href="#t_primitive">i1</a> result, as follows:
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3975	<ol>
				3976	<li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
				3977	<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]	3978	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3979	<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]	3980	<tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3981	<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]	3982	<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]	3983	<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]	3984	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3985	<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]	3986	<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]	3987	<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]	3988	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3989	<li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
				3990	<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]	3991	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3992	<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]	3993	<tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3994	<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]	3995	<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]	3996	<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]	3997	<tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3998	<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]	3999	<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]	4000	<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]	4001	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4002	<li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
				4003	<li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
				4004	</ol>
				4005
				4006	<h5>Example:</h5>
				4007	<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]	4008	<result> = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
				4009	<result> = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
				4010	<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]	4011	</pre>
				4012	</div>
				4013
				4014	<!-- _______________________________________________________________________ -->
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4015	<div class="doc_subsubsection">
				4016	<a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
				4017	</div>
				4018	<div class="doc_text">
				4019	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4020	<pre> <result> = vicmp <cond> <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4021	</pre>
				4022	<h5>Overview:</h5>
				4023	<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
				4024	element-wise comparison of its two integer vector operands.</p>
				4025	<h5>Arguments:</h5>
				4026	<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
				4027	the condition code indicating the kind of comparison to perform. It is not
				4028	a value, just a keyword. The possible condition code are:
				4029	<ol>
				4030	<li><tt>eq</tt>: equal</li>
				4031	<li><tt>ne</tt>: not equal </li>
				4032	<li><tt>ugt</tt>: unsigned greater than</li>
				4033	<li><tt>uge</tt>: unsigned greater or equal</li>
				4034	<li><tt>ult</tt>: unsigned less than</li>
				4035	<li><tt>ule</tt>: unsigned less or equal</li>
				4036	<li><tt>sgt</tt>: signed greater than</li>
				4037	<li><tt>sge</tt>: signed greater or equal</li>
				4038	<li><tt>slt</tt>: signed less than</li>
				4039	<li><tt>sle</tt>: signed less or equal</li>
				4040	</ol>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4041	<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]	4042	<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
				4043	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4044	<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]	4045	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4046	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
				4047	identical type as the values being compared. The most significant bit in each
				4048	element is 1 if the element-wise comparison evaluates to true, and is 0
				4049	otherwise. All other bits of the result are undefined. The condition codes
				4050	are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
				4051	instruction</a>.
				4052
				4053	<h5>Example:</h5>
				4054	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4055	<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>
				4056	<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]	4057	</pre>
				4058	</div>
				4059
				4060	<!-- _______________________________________________________________________ -->
				4061	<div class="doc_subsubsection">
				4062	<a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
				4063	</div>
				4064	<div class="doc_text">
				4065	<h5>Syntax:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4066	<pre> <result> = vfcmp <cond> <ty> <op1>, <op2></pre>
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4067	<h5>Overview:</h5>
				4068	<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
				4069	element-wise comparison of its two floating point vector operands. The output
				4070	elements have the same width as the input elements.</p>
				4071	<h5>Arguments:</h5>
				4072	<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
				4073	the condition code indicating the kind of comparison to perform. It is not
				4074	a value, just a keyword. The possible condition code are:
				4075	<ol>
				4076	<li><tt>false</tt>: no comparison, always returns false</li>
				4077	<li><tt>oeq</tt>: ordered and equal</li>
				4078	<li><tt>ogt</tt>: ordered and greater than </li>
				4079	<li><tt>oge</tt>: ordered and greater than or equal</li>
				4080	<li><tt>olt</tt>: ordered and less than </li>
				4081	<li><tt>ole</tt>: ordered and less than or equal</li>
				4082	<li><tt>one</tt>: ordered and not equal</li>
				4083	<li><tt>ord</tt>: ordered (no nans)</li>
				4084	<li><tt>ueq</tt>: unordered or equal</li>
				4085	<li><tt>ugt</tt>: unordered or greater than </li>
				4086	<li><tt>uge</tt>: unordered or greater than or equal</li>
				4087	<li><tt>ult</tt>: unordered or less than </li>
				4088	<li><tt>ule</tt>: unordered or less than or equal</li>
				4089	<li><tt>une</tt>: unordered or not equal</li>
				4090	<li><tt>uno</tt>: unordered (either nans)</li>
				4091	<li><tt>true</tt>: no comparison, always returns true</li>
				4092	</ol>
				4093	<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
				4094	<a href="#t_floating">floating point</a> typed. They must also be identical
				4095	types.</p>
				4096	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4097	<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]	4098	according to the condition code given as <tt>cond</tt>. The comparison yields a
				4099	<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
				4100	an identical number of elements as the values being compared, and each element
				4101	having identical with to the width of the floating point elements. The most
				4102	significant bit in each element is 1 if the element-wise comparison evaluates to
				4103	true, and is 0 otherwise. All other bits of the result are undefined. The
				4104	condition codes are evaluated identically to the
				4105	<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
				4106
				4107	<h5>Example:</h5>
				4108	<pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4109	<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>
				4110	<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]	4111	</pre>
				4112	</div>
				4113
				4114	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4115	<div class="doc_subsubsection">
				4116	<a name="i_phi">'<tt>phi</tt>' Instruction</a>
				4117	</div>
				4118
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4119	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4120
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4121	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4122
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4123	<pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre>
				4124	<h5>Overview:</h5>
				4125	<p>The '<tt>phi</tt>' instruction is used to implement the φ node in
				4126	the SSA graph representing the function.</p>
				4127	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4128
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4129	<p>The type of the incoming values is specified with the first type
				4130	field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
				4131	as arguments, with one pair for each predecessor basic block of the
				4132	current block. Only values of <a href="#t_firstclass">first class</a>
				4133	type may be used as the value arguments to the PHI node. Only labels
				4134	may be used as the label arguments.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4135
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4136	<p>There must be no non-phi instructions between the start of a basic
				4137	block and the PHI instructions: i.e. PHI instructions must be first in
				4138	a basic block.</p>
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	<h5>Semantics:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4141
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4142	<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
				4143	specified by the pair corresponding to the predecessor basic block that executed
				4144	just prior to the current block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4145
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4146	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4147	<pre>
				4148	Loop: ; Infinite loop that counts from 0 on up...
				4149	%indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
				4150	%nextindvar = add i32 %indvar, 1
				4151	br label %Loop
				4152	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4153	</div>
				4154
				4155	<!-- _______________________________________________________________________ -->
				4156	<div class="doc_subsubsection">
				4157	<a name="i_select">'<tt>select</tt>' Instruction</a>
				4158	</div>
				4159
				4160	<div class="doc_text">
				4161
				4162	<h5>Syntax:</h5>
				4163
				4164	<pre>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4165	<result> = select <i>selty</i> <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
				4166
				4167	<i>selty</i> is either i1 or {<N x i1&gt}
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4168	</pre>
				4169
				4170	<h5>Overview:</h5>
				4171
				4172	<p>
				4173	The '<tt>select</tt>' instruction is used to choose one value based on a
				4174	condition, without branching.
				4175	</p>
				4176
				4177
				4178	<h5>Arguments:</h5>
				4179
				4180	<p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4181	The '<tt>select</tt>' instruction requires an 'i1' value or
				4182	a vector of 'i1' values indicating the
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4183	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]	4184	type. If the val1/val2 are vectors and
				4185	the condition is a scalar, then entire vectors are selected, not
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4186	individual elements.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4187	</p>
				4188
				4189	<h5>Semantics:</h5>
				4190
				4191	<p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4192	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]	4193	value argument; otherwise, it returns the second value argument.
				4194	</p>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4195	<p>
				4196	If the condition is a vector of i1, then the value arguments must
				4197	be vectors of the same size, and the selection is done element
				4198	by element.
				4199	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4200
				4201	<h5>Example:</h5>
				4202
				4203	<pre>
				4204	%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
				4205	</pre>
				4206	</div>
				4207
				4208
				4209	<!-- _______________________________________________________________________ -->
				4210	<div class="doc_subsubsection">
				4211	<a name="i_call">'<tt>call</tt>' Instruction</a>
				4212	</div>
				4213
				4214	<div class="doc_text">
				4215
				4216	<h5>Syntax:</h5>
				4217	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4218	<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]	4219	</pre>
				4220
				4221	<h5>Overview:</h5>
				4222
				4223	<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
				4224
				4225	<h5>Arguments:</h5>
				4226
				4227	<p>This instruction requires several arguments:</p>
				4228
				4229	<ol>
				4230	<li>
				4231	<p>The optional "tail" marker indicates whether the callee function accesses
				4232	any allocas or varargs in the caller. If the "tail" marker is present, the
				4233	function call is eligible for tail call optimization. Note that calls may
				4234	be marked "tail" even if they do not occur before a <a
				4235	href="#i_ret"><tt>ret</tt></a> instruction.
				4236	</li>
				4237	<li>
				4238	<p>The optional "cconv" marker indicates which <a href="#callingconv">calling
				4239	convention</a> the call should use. If none is specified, the call defaults
				4240	to using C calling conventions.
				4241	</li>
				4242	<li>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4243	<p>'<tt>ty</tt>': the type of the call instruction itself which is also
				4244	the type of the return value. Functions that return no value are marked
				4245	<tt><a href="#t_void">void</a></tt>.</p>
				4246	</li>
				4247	<li>
				4248	<p>'<tt>fnty</tt>': shall be the signature of the pointer to function
				4249	value being invoked. The argument types must match the types implied by
				4250	this signature. This type can be omitted if the function is not varargs
				4251	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]	4252	</li>
				4253	<li>
				4254	<p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
				4255	be invoked. In most cases, this is a direct function invocation, but
				4256	indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
				4257	to function value.</p>
				4258	</li>
				4259	<li>
				4260	<p>'<tt>function args</tt>': argument list whose types match the
				4261	function signature argument types. All arguments must be of
				4262	<a href="#t_firstclass">first class</a> type. If the function signature
				4263	indicates the function accepts a variable number of arguments, the extra
				4264	arguments can be specified.</p>
				4265	</li>
				4266	</ol>
				4267
				4268	<h5>Semantics:</h5>
				4269
				4270	<p>The '<tt>call</tt>' instruction is used to cause control flow to
				4271	transfer to a specified function, with its incoming arguments bound to
				4272	the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
				4273	instruction in the called function, control flow continues with the
				4274	instruction after the function call, and the return value of the
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4275	function is bound to the result argument. If the callee returns multiple
				4276	values then the return values of the function are only accessible through
				4277	the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4278
				4279	<h5>Example:</h5>
				4280
				4281	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4282	%retval = call i32 @test(i32 %argc)
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4283	call i32 (i8 , ...) @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
				4284	%X = tail call i32 @foo() <i>; yields i32</i>
				4285	%Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
				4286	call void %foo(i8 97 signext)
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4287
				4288	%struct.A = type { i32, i8 }
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4289	%r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
				4290	%gr = getresult %struct.A %r, 0 <i>; yields i32</i>
				4291	%gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4292	</pre>
				4293
				4294	</div>
				4295
				4296	<!-- _______________________________________________________________________ -->
				4297	<div class="doc_subsubsection">
				4298	<a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
				4299	</div>
				4300
				4301	<div class="doc_text">
				4302
				4303	<h5>Syntax:</h5>
				4304
				4305	<pre>
				4306	<resultval> = va_arg <va_list*> <arglist>, <argty>
				4307	</pre>
				4308
				4309	<h5>Overview:</h5>
				4310
				4311	<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
				4312	the "variable argument" area of a function call. It is used to implement the
				4313	<tt>va_arg</tt> macro in C.</p>
				4314
				4315	<h5>Arguments:</h5>
				4316
				4317	<p>This instruction takes a <tt>va_list*</tt> value and the type of
				4318	the argument. It returns a value of the specified argument type and
				4319	increments the <tt>va_list</tt> to point to the next argument. The
				4320	actual type of <tt>va_list</tt> is target specific.</p>
				4321
				4322	<h5>Semantics:</h5>
				4323
				4324	<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
				4325	type from the specified <tt>va_list</tt> and causes the
				4326	<tt>va_list</tt> to point to the next argument. For more information,
				4327	see the variable argument handling <a href="#int_varargs">Intrinsic
				4328	Functions</a>.</p>
				4329
				4330	<p>It is legal for this instruction to be called in a function which does not
				4331	take a variable number of arguments, for example, the <tt>vfprintf</tt>
				4332	function.</p>
				4333
				4334	<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
				4335	href="#intrinsics">intrinsic function</a> because it takes a type as an
				4336	argument.</p>
				4337
				4338	<h5>Example:</h5>
				4339
				4340	<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
				4341
				4342	</div>
				4343
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4344	<!-- _______________________________________________________________________ -->
				4345	<div class="doc_subsubsection">
				4346	<a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
				4347	</div>
				4348
				4349	<div class="doc_text">
				4350
				4351	<h5>Syntax:</h5>
				4352	<pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4353	<resultval> = getresult <type> <retval>, <index>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4354	</pre>
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4355
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4356	<h5>Overview:</h5>
				4357
				4358	<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4359	from a '<tt><a href="#i_call">call</a></tt>'
				4360	or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
				4361	results.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4362
				4363	<h5>Arguments:</h5>
				4364
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4365	<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]	4366	first argument, or an undef value. The value must have <a
				4367	href="#t_struct">structure type</a>. The second argument is a constant
				4368	unsigned index value which must be in range for the number of values returned
				4369	by the call.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4370
				4371	<h5>Semantics:</h5>
				4372
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4373	<p>The '<tt>getresult</tt>' instruction extracts the element identified by
				4374	'<tt>index</tt>' from the aggregate value.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4375
				4376	<h5>Example:</h5>
				4377
				4378	<pre>
				4379	%struct.A = type { i32, i8 }
				4380
				4381	%r = call %struct.A @foo()
Chris Lattner	ee9da3f	2008-03-21 17:20:51 +0000	[diff] [blame]	4382	%gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
				4383	%gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4384	add i32 %gr, 42
				4385	add i8 %gr1, 41
				4386	</pre>
				4387
				4388	</div>
				4389
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4390	<!-- *********************************************************************** -->
				4391	<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
				4392	<!-- *********************************************************************** -->
				4393
				4394	<div class="doc_text">
				4395
				4396	<p>LLVM supports the notion of an "intrinsic function". These functions have
				4397	well known names and semantics and are required to follow certain restrictions.
				4398	Overall, these intrinsics represent an extension mechanism for the LLVM
				4399	language that does not require changing all of the transformations in LLVM when
				4400	adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
				4401
				4402	<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
				4403	prefix is reserved in LLVM for intrinsic names; thus, function names may not
				4404	begin with this prefix. Intrinsic functions must always be external functions:
				4405	you cannot define the body of intrinsic functions. Intrinsic functions may
				4406	only be used in call or invoke instructions: it is illegal to take the address
				4407	of an intrinsic function. Additionally, because intrinsic functions are part
				4408	of the LLVM language, it is required if any are added that they be documented
				4409	here.</p>
				4410
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4411	<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
				4412	a family of functions that perform the same operation but on different data
				4413	types. Because LLVM can represent over 8 million different integer types,
				4414	overloading is used commonly to allow an intrinsic function to operate on any
				4415	integer type. One or more of the argument types or the result type can be
				4416	overloaded to accept any integer type. Argument types may also be defined as
				4417	exactly matching a previous argument's type or the result type. This allows an
				4418	intrinsic function which accepts multiple arguments, but needs all of them to
				4419	be of the same type, to only be overloaded with respect to a single argument or
				4420	the result.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4421
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	4422	<p>Overloaded intrinsics will have the names of its overloaded argument types
				4423	encoded into its function name, each preceded by a period. Only those types
				4424	which are overloaded result in a name suffix. Arguments whose type is matched
				4425	against another type do not. For example, the <tt>llvm.ctpop</tt> function can
				4426	take an integer of any width and returns an integer of exactly the same integer
				4427	width. This leads to a family of functions such as
				4428	<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
				4429	Only one type, the return type, is overloaded, and only one type suffix is
				4430	required. Because the argument's type is matched against the return type, it
				4431	does not require its own name suffix.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4432
				4433	<p>To learn how to add an intrinsic function, please see the
				4434	<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
				4435	</p>
				4436
				4437	</div>
				4438
				4439	<!-- ======================================================================= -->
				4440	<div class="doc_subsection">
				4441	<a name="int_varargs">Variable Argument Handling Intrinsics</a>
				4442	</div>
				4443
				4444	<div class="doc_text">
				4445
				4446	<p>Variable argument support is defined in LLVM with the <a
				4447	href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
				4448	intrinsic functions. These functions are related to the similarly
				4449	named macros defined in the <tt><stdarg.h></tt> header file.</p>
				4450
				4451	<p>All of these functions operate on arguments that use a
				4452	target-specific value type "<tt>va_list</tt>". The LLVM assembly
				4453	language reference manual does not define what this type is, so all
				4454	transformations should be prepared to handle these functions regardless of
				4455	the type used.</p>
				4456
				4457	<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
				4458	instruction and the variable argument handling intrinsic functions are
				4459	used.</p>
				4460
				4461	<div class="doc_code">
				4462	<pre>
				4463	define i32 @test(i32 %X, ...) {
				4464	; Initialize variable argument processing
				4465	%ap = alloca i8*
				4466	%ap2 = bitcast i8** %ap to i8*
				4467	call void @llvm.va_start(i8* %ap2)
				4468
				4469	; Read a single integer argument
				4470	%tmp = va_arg i8** %ap, i32
				4471
				4472	; Demonstrate usage of llvm.va_copy and llvm.va_end
				4473	%aq = alloca i8*
				4474	%aq2 = bitcast i8** %aq to i8*
				4475	call void @llvm.va_copy(i8* %aq2, i8* %ap2)
				4476	call void @llvm.va_end(i8* %aq2)
				4477
				4478	; Stop processing of arguments.
				4479	call void @llvm.va_end(i8* %ap2)
				4480	ret i32 %tmp
				4481	}
				4482
				4483	declare void @llvm.va_start(i8*)
				4484	declare void @llvm.va_copy(i8, i8)
				4485	declare void @llvm.va_end(i8*)
				4486	</pre>
				4487	</div>
				4488
				4489	</div>
				4490
				4491	<!-- _______________________________________________________________________ -->
				4492	<div class="doc_subsubsection">
				4493	<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
				4494	</div>
				4495
				4496
				4497	<div class="doc_text">
				4498	<h5>Syntax:</h5>
				4499	<pre> declare void %llvm.va_start(i8* <arglist>)<br></pre>
				4500	<h5>Overview:</h5>
				4501	<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
				4502	<tt>*<arglist></tt> for subsequent use by <tt><a
				4503	href="#i_va_arg">va_arg</a></tt>.</p>
				4504
				4505	<h5>Arguments:</h5>
				4506
				4507	<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
				4508
				4509	<h5>Semantics:</h5>
				4510
				4511	<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
				4512	macro available in C. In a target-dependent way, it initializes the
				4513	<tt>va_list</tt> element to which the argument points, so that the next call to
				4514	<tt>va_arg</tt> will produce the first variable argument passed to the function.
				4515	Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
				4516	last argument of the function as the compiler can figure that out.</p>
				4517
				4518	</div>
				4519
				4520	<!-- _______________________________________________________________________ -->
				4521	<div class="doc_subsubsection">
				4522	<a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
				4523	</div>
				4524
				4525	<div class="doc_text">
				4526	<h5>Syntax:</h5>
				4527	<pre> declare void @llvm.va_end(i8* <arglist>)<br></pre>
				4528	<h5>Overview:</h5>
				4529
				4530	<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
				4531	which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
				4532	or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
				4533
				4534	<h5>Arguments:</h5>
				4535
				4536	<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
				4537
				4538	<h5>Semantics:</h5>
				4539
				4540	<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
				4541	macro available in C. In a target-dependent way, it destroys the
				4542	<tt>va_list</tt> element to which the argument points. Calls to <a
				4543	href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
				4544	<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
				4545	<tt>llvm.va_end</tt>.</p>
				4546
				4547	</div>
				4548
				4549	<!-- _______________________________________________________________________ -->
				4550	<div class="doc_subsubsection">
				4551	<a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
				4552	</div>
				4553
				4554	<div class="doc_text">
				4555
				4556	<h5>Syntax:</h5>
				4557
				4558	<pre>
				4559	declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)
				4560	</pre>
				4561
				4562	<h5>Overview:</h5>
				4563
				4564	<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
				4565	from the source argument list to the destination argument list.</p>
				4566
				4567	<h5>Arguments:</h5>
				4568
				4569	<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
				4570	The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
				4571
				4572
				4573	<h5>Semantics:</h5>
				4574
				4575	<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
				4576	macro available in C. In a target-dependent way, it copies the source
				4577	<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
				4578	intrinsic is necessary because the <tt><a href="#int_va_start">
				4579	llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
				4580	example, memory allocation.</p>
				4581
				4582	</div>
				4583
				4584	<!-- ======================================================================= -->
				4585	<div class="doc_subsection">
				4586	<a name="int_gc">Accurate Garbage Collection Intrinsics</a>
				4587	</div>
				4588
				4589	<div class="doc_text">
				4590
				4591	<p>
				4592	LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	4593	Collection</a> (GC) requires the implementation and generation of these
				4594	intrinsics.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4595	These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
				4596	stack</a>, as well as garbage collector implementations that require <a
				4597	href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
				4598	Front-ends for type-safe garbage collected languages should generate these
				4599	intrinsics to make use of the LLVM garbage collectors. For more details, see <a
				4600	href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
				4601	</p>
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	4602
				4603	<p>The garbage collection intrinsics only operate on objects in the generic
				4604	address space (address space zero).</p>
				4605
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4606	</div>
				4607
				4608	<!-- _______________________________________________________________________ -->
				4609	<div class="doc_subsubsection">
				4610	<a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
				4611	</div>
				4612
				4613	<div class="doc_text">
				4614
				4615	<h5>Syntax:</h5>
				4616
				4617	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4618	declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4619	</pre>
				4620
				4621	<h5>Overview:</h5>
				4622
				4623	<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
				4624	the code generator, and allows some metadata to be associated with it.</p>
				4625
				4626	<h5>Arguments:</h5>
				4627
				4628	<p>The first argument specifies the address of a stack object that contains the
				4629	root pointer. The second pointer (which must be either a constant or a global
				4630	value address) contains the meta-data to be associated with the root.</p>
				4631
				4632	<h5>Semantics:</h5>
				4633
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	4634	<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]	4635	location. At compile-time, the code generator generates information to allow
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4636	the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
				4637	intrinsic may only be used in a function which <a href="#gc">specifies a GC
				4638	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4639
				4640	</div>
				4641
				4642
				4643	<!-- _______________________________________________________________________ -->
				4644	<div class="doc_subsubsection">
				4645	<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
				4646	</div>
				4647
				4648	<div class="doc_text">
				4649
				4650	<h5>Syntax:</h5>
				4651
				4652	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4653	declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4654	</pre>
				4655
				4656	<h5>Overview:</h5>
				4657
				4658	<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
				4659	locations, allowing garbage collector implementations that require read
				4660	barriers.</p>
				4661
				4662	<h5>Arguments:</h5>
				4663
				4664	<p>The second argument is the address to read from, which should be an address
				4665	allocated from the garbage collector. The first object is a pointer to the
				4666	start of the referenced object, if needed by the language runtime (otherwise
				4667	null).</p>
				4668
				4669	<h5>Semantics:</h5>
				4670
				4671	<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
				4672	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4673	garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
				4674	may only be used in a function which <a href="#gc">specifies a GC
				4675	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4676
				4677	</div>
				4678
				4679
				4680	<!-- _______________________________________________________________________ -->
				4681	<div class="doc_subsubsection">
				4682	<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
				4683	</div>
				4684
				4685	<div class="doc_text">
				4686
				4687	<h5>Syntax:</h5>
				4688
				4689	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4690	declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4691	</pre>
				4692
				4693	<h5>Overview:</h5>
				4694
				4695	<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
				4696	locations, allowing garbage collector implementations that require write
				4697	barriers (such as generational or reference counting collectors).</p>
				4698
				4699	<h5>Arguments:</h5>
				4700
				4701	<p>The first argument is the reference to store, the second is the start of the
				4702	object to store it to, and the third is the address of the field of Obj to
				4703	store to. If the runtime does not require a pointer to the object, Obj may be
				4704	null.</p>
				4705
				4706	<h5>Semantics:</h5>
				4707
				4708	<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
				4709	instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen	4039354	2007-12-25 02:31:26 +0000	[diff] [blame]	4710	garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
				4711	may only be used in a function which <a href="#gc">specifies a GC
				4712	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4713
				4714	</div>
				4715
				4716
				4717
				4718	<!-- ======================================================================= -->
				4719	<div class="doc_subsection">
				4720	<a name="int_codegen">Code Generator Intrinsics</a>
				4721	</div>
				4722
				4723	<div class="doc_text">
				4724	<p>
				4725	These intrinsics are provided by LLVM to expose special features that may only
				4726	be implemented with code generator support.
				4727	</p>
				4728
				4729	</div>
				4730
				4731	<!-- _______________________________________________________________________ -->
				4732	<div class="doc_subsubsection">
				4733	<a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
				4734	</div>
				4735
				4736	<div class="doc_text">
				4737
				4738	<h5>Syntax:</h5>
				4739	<pre>
				4740	declare i8 *@llvm.returnaddress(i32 <level>)
				4741	</pre>
				4742
				4743	<h5>Overview:</h5>
				4744
				4745	<p>
				4746	The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
				4747	target-specific value indicating the return address of the current function
				4748	or one of its callers.
				4749	</p>
				4750
				4751	<h5>Arguments:</h5>
				4752
				4753	<p>
				4754	The argument to this intrinsic indicates which function to return the address
				4755	for. Zero indicates the calling function, one indicates its caller, etc. The
				4756	argument is <b>required</b> to be a constant integer value.
				4757	</p>
				4758
				4759	<h5>Semantics:</h5>
				4760
				4761	<p>
				4762	The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
				4763	the return address of the specified call frame, or zero if it cannot be
				4764	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4765	for arguments other than zero, so it should only be used for debugging purposes.
				4766	</p>
				4767
				4768	<p>
				4769	Note that calling this intrinsic does not prevent function inlining or other
				4770	aggressive transformations, so the value returned may not be that of the obvious
				4771	source-language caller.
				4772	</p>
				4773	</div>
				4774
				4775
				4776	<!-- _______________________________________________________________________ -->
				4777	<div class="doc_subsubsection">
				4778	<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
				4779	</div>
				4780
				4781	<div class="doc_text">
				4782
				4783	<h5>Syntax:</h5>
				4784	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4785	declare i8 *@llvm.frameaddress(i32 <level>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4786	</pre>
				4787
				4788	<h5>Overview:</h5>
				4789
				4790	<p>
				4791	The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
				4792	target-specific frame pointer value for the specified stack frame.
				4793	</p>
				4794
				4795	<h5>Arguments:</h5>
				4796
				4797	<p>
				4798	The argument to this intrinsic indicates which function to return the frame
				4799	pointer for. Zero indicates the calling function, one indicates its caller,
				4800	etc. The argument is <b>required</b> to be a constant integer value.
				4801	</p>
				4802
				4803	<h5>Semantics:</h5>
				4804
				4805	<p>
				4806	The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
				4807	the frame address of the specified call frame, or zero if it cannot be
				4808	identified. The value returned by this intrinsic is likely to be incorrect or 0
				4809	for arguments other than zero, so it should only be used for debugging purposes.
				4810	</p>
				4811
				4812	<p>
				4813	Note that calling this intrinsic does not prevent function inlining or other
				4814	aggressive transformations, so the value returned may not be that of the obvious
				4815	source-language caller.
				4816	</p>
				4817	</div>
				4818
				4819	<!-- _______________________________________________________________________ -->
				4820	<div class="doc_subsubsection">
				4821	<a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
				4822	</div>
				4823
				4824	<div class="doc_text">
				4825
				4826	<h5>Syntax:</h5>
				4827	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4828	declare i8 *@llvm.stacksave()
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4829	</pre>
				4830
				4831	<h5>Overview:</h5>
				4832
				4833	<p>
				4834	The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
				4835	the function stack, for use with <a href="#int_stackrestore">
				4836	<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
				4837	features like scoped automatic variable sized arrays in C99.
				4838	</p>
				4839
				4840	<h5>Semantics:</h5>
				4841
				4842	<p>
				4843	This intrinsic returns a opaque pointer value that can be passed to <a
				4844	href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
				4845	<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
				4846	<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
				4847	state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
				4848	practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
				4849	that were allocated after the <tt>llvm.stacksave</tt> was executed.
				4850	</p>
				4851
				4852	</div>
				4853
				4854	<!-- _______________________________________________________________________ -->
				4855	<div class="doc_subsubsection">
				4856	<a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
				4857	</div>
				4858
				4859	<div class="doc_text">
				4860
				4861	<h5>Syntax:</h5>
				4862	<pre>
				4863	declare void @llvm.stackrestore(i8 * %ptr)
				4864	</pre>
				4865
				4866	<h5>Overview:</h5>
				4867
				4868	<p>
				4869	The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
				4870	the function stack to the state it was in when the corresponding <a
				4871	href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
				4872	useful for implementing language features like scoped automatic variable sized
				4873	arrays in C99.
				4874	</p>
				4875
				4876	<h5>Semantics:</h5>
				4877
				4878	<p>
				4879	See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
				4880	</p>
				4881
				4882	</div>
				4883
				4884
				4885	<!-- _______________________________________________________________________ -->
				4886	<div class="doc_subsubsection">
				4887	<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
				4888	</div>
				4889
				4890	<div class="doc_text">
				4891
				4892	<h5>Syntax:</h5>
				4893	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4894	declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4895	</pre>
				4896
				4897	<h5>Overview:</h5>
				4898
				4899
				4900	<p>
				4901	The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
				4902	a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
				4903	no
				4904	effect on the behavior of the program but can change its performance
				4905	characteristics.
				4906	</p>
				4907
				4908	<h5>Arguments:</h5>
				4909
				4910	<p>
				4911	<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
				4912	determining if the fetch should be for a read (0) or write (1), and
				4913	<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
				4914	locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
				4915	<tt>locality</tt> arguments must be constant integers.
				4916	</p>
				4917
				4918	<h5>Semantics:</h5>
				4919
				4920	<p>
				4921	This intrinsic does not modify the behavior of the program. In particular,
				4922	prefetches cannot trap and do not produce a value. On targets that support this
				4923	intrinsic, the prefetch can provide hints to the processor cache for better
				4924	performance.
				4925	</p>
				4926
				4927	</div>
				4928
				4929	<!-- _______________________________________________________________________ -->
				4930	<div class="doc_subsubsection">
				4931	<a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
				4932	</div>
				4933
				4934	<div class="doc_text">
				4935
				4936	<h5>Syntax:</h5>
				4937	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	4938	declare void @llvm.pcmarker(i32 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4939	</pre>
				4940
				4941	<h5>Overview:</h5>
				4942
				4943
				4944	<p>
				4945	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]	4946	(PC) in a region of
				4947	code to simulators and other tools. The method is target specific, but it is
				4948	expected that the marker will use exported symbols to transmit the PC of the
				4949	marker.
				4950	The marker makes no guarantees that it will remain with any specific instruction
				4951	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]	4952	optimizations. The intended use is to be inserted after optimizations to allow
				4953	correlations of simulation runs.
				4954	</p>
				4955
				4956	<h5>Arguments:</h5>
				4957
				4958	<p>
				4959	<tt>id</tt> is a numerical id identifying the marker.
				4960	</p>
				4961
				4962	<h5>Semantics:</h5>
				4963
				4964	<p>
				4965	This intrinsic does not modify the behavior of the program. Backends that do not
				4966	support this intrinisic may ignore it.
				4967	</p>
				4968
				4969	</div>
				4970
				4971	<!-- _______________________________________________________________________ -->
				4972	<div class="doc_subsubsection">
				4973	<a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
				4974	</div>
				4975
				4976	<div class="doc_text">
				4977
				4978	<h5>Syntax:</h5>
				4979	<pre>
				4980	declare i64 @llvm.readcyclecounter( )
				4981	</pre>
				4982
				4983	<h5>Overview:</h5>
				4984
				4985
				4986	<p>
				4987	The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
				4988	counter register (or similar low latency, high accuracy clocks) on those targets
				4989	that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
				4990	As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
				4991	should only be used for small timings.
				4992	</p>
				4993
				4994	<h5>Semantics:</h5>
				4995
				4996	<p>
				4997	When directly supported, reading the cycle counter should not modify any memory.
				4998	Implementations are allowed to either return a application specific value or a
				4999	system wide value. On backends without support, this is lowered to a constant 0.
				5000	</p>
				5001
				5002	</div>
				5003
				5004	<!-- ======================================================================= -->
				5005	<div class="doc_subsection">
				5006	<a name="int_libc">Standard C Library Intrinsics</a>
				5007	</div>
				5008
				5009	<div class="doc_text">
				5010	<p>
				5011	LLVM provides intrinsics for a few important standard C library functions.
				5012	These intrinsics allow source-language front-ends to pass information about the
				5013	alignment of the pointer arguments to the code generator, providing opportunity
				5014	for more efficient code generation.
				5015	</p>
				5016
				5017	</div>
				5018
				5019	<!-- _______________________________________________________________________ -->
				5020	<div class="doc_subsubsection">
				5021	<a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
				5022	</div>
				5023
				5024	<div class="doc_text">
				5025
				5026	<h5>Syntax:</h5>
				5027	<pre>
				5028	declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
				5029	i32 <len>, i32 <align>)
				5030	declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>,
				5031	i64 <len>, i32 <align>)
				5032	</pre>
				5033
				5034	<h5>Overview:</h5>
				5035
				5036	<p>
				5037	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5038	location to the destination location.
				5039	</p>
				5040
				5041	<p>
				5042	Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
				5043	intrinsics do not return a value, and takes an extra alignment argument.
				5044	</p>
				5045
				5046	<h5>Arguments:</h5>
				5047
				5048	<p>
				5049	The first argument is a pointer to the destination, the second is a pointer to
				5050	the source. The third argument is an integer argument
				5051	specifying the number of bytes to copy, and the fourth argument is the alignment
				5052	of the source and destination locations.
				5053	</p>
				5054
				5055	<p>
				5056	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5057	the caller guarantees that both the source and destination pointers are aligned
				5058	to that boundary.
				5059	</p>
				5060
				5061	<h5>Semantics:</h5>
				5062
				5063	<p>
				5064	The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
				5065	location to the destination location, which are not allowed to overlap. It
				5066	copies "len" bytes of memory over. If the argument is known to be aligned to
				5067	some boundary, this can be specified as the fourth argument, otherwise it should
				5068	be set to 0 or 1.
				5069	</p>
				5070	</div>
				5071
				5072
				5073	<!-- _______________________________________________________________________ -->
				5074	<div class="doc_subsubsection">
				5075	<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
				5076	</div>
				5077
				5078	<div class="doc_text">
				5079
				5080	<h5>Syntax:</h5>
				5081	<pre>
				5082	declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
				5083	i32 <len>, i32 <align>)
				5084	declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>,
				5085	i64 <len>, i32 <align>)
				5086	</pre>
				5087
				5088	<h5>Overview:</h5>
				5089
				5090	<p>
				5091	The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
				5092	location to the destination location. It is similar to the
Chris Lattner	dba16ea	2008-01-06 19:51:52 +0000	[diff] [blame]	5093	'<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]	5094	</p>
				5095
				5096	<p>
				5097	Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
				5098	intrinsics do not return a value, and takes an extra alignment argument.
				5099	</p>
				5100
				5101	<h5>Arguments:</h5>
				5102
				5103	<p>
				5104	The first argument is a pointer to the destination, the second is a pointer to
				5105	the source. The third argument is an integer argument
				5106	specifying the number of bytes to copy, and the fourth argument is the alignment
				5107	of the source and destination locations.
				5108	</p>
				5109
				5110	<p>
				5111	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5112	the caller guarantees that the source and destination pointers are aligned to
				5113	that boundary.
				5114	</p>
				5115
				5116	<h5>Semantics:</h5>
				5117
				5118	<p>
				5119	The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
				5120	location to the destination location, which may overlap. It
				5121	copies "len" bytes of memory over. If the argument is known to be aligned to
				5122	some boundary, this can be specified as the fourth argument, otherwise it should
				5123	be set to 0 or 1.
				5124	</p>
				5125	</div>
				5126
				5127
				5128	<!-- _______________________________________________________________________ -->
				5129	<div class="doc_subsubsection">
				5130	<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
				5131	</div>
				5132
				5133	<div class="doc_text">
				5134
				5135	<h5>Syntax:</h5>
				5136	<pre>
				5137	declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
				5138	i32 <len>, i32 <align>)
				5139	declare void @llvm.memset.i64(i8 * <dest>, i8 <val>,
				5140	i64 <len>, i32 <align>)
				5141	</pre>
				5142
				5143	<h5>Overview:</h5>
				5144
				5145	<p>
				5146	The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
				5147	byte value.
				5148	</p>
				5149
				5150	<p>
				5151	Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
				5152	does not return a value, and takes an extra alignment argument.
				5153	</p>
				5154
				5155	<h5>Arguments:</h5>
				5156
				5157	<p>
				5158	The first argument is a pointer to the destination to fill, the second is the
				5159	byte value to fill it with, the third argument is an integer
				5160	argument specifying the number of bytes to fill, and the fourth argument is the
				5161	known alignment of destination location.
				5162	</p>
				5163
				5164	<p>
				5165	If the call to this intrinisic has an alignment value that is not 0 or 1, then
				5166	the caller guarantees that the destination pointer is aligned to that boundary.
				5167	</p>
				5168
				5169	<h5>Semantics:</h5>
				5170
				5171	<p>
				5172	The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
				5173	the
				5174	destination location. If the argument is known to be aligned to some boundary,
				5175	this can be specified as the fourth argument, otherwise it should be set to 0 or
				5176	1.
				5177	</p>
				5178	</div>
				5179
				5180
				5181	<!-- _______________________________________________________________________ -->
				5182	<div class="doc_subsubsection">
				5183	<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
				5184	</div>
				5185
				5186	<div class="doc_text">
				5187
				5188	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5189	<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]	5190	floating point or vector of floating point type. Not all targets support all
				5191	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5192	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5193	declare float @llvm.sqrt.f32(float %Val)
				5194	declare double @llvm.sqrt.f64(double %Val)
				5195	declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
				5196	declare fp128 @llvm.sqrt.f128(fp128 %Val)
				5197	declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5198	</pre>
				5199
				5200	<h5>Overview:</h5>
				5201
				5202	<p>
				5203	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]	5204	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]	5205	<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]	5206	negative numbers other than -0.0 (which allows for better optimization, because
				5207	there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
				5208	defined to return -0.0 like IEEE sqrt.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5209	</p>
				5210
				5211	<h5>Arguments:</h5>
				5212
				5213	<p>
				5214	The argument and return value are floating point numbers of the same type.
				5215	</p>
				5216
				5217	<h5>Semantics:</h5>
				5218
				5219	<p>
				5220	This function returns the sqrt of the specified operand if it is a nonnegative
				5221	floating point number.
				5222	</p>
				5223	</div>
				5224
				5225	<!-- _______________________________________________________________________ -->
				5226	<div class="doc_subsubsection">
				5227	<a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
				5228	</div>
				5229
				5230	<div class="doc_text">
				5231
				5232	<h5>Syntax:</h5>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5233	<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]	5234	floating point or vector of floating point type. Not all targets support all
				5235	types however.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5236	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5237	declare float @llvm.powi.f32(float %Val, i32 %power)
				5238	declare double @llvm.powi.f64(double %Val, i32 %power)
				5239	declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
				5240	declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
				5241	declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5242	</pre>
				5243
				5244	<h5>Overview:</h5>
				5245
				5246	<p>
				5247	The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
				5248	specified (positive or negative) power. The order of evaluation of
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5249	multiplications is not defined. When a vector of floating point type is
				5250	used, the second argument remains a scalar integer value.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5251	</p>
				5252
				5253	<h5>Arguments:</h5>
				5254
				5255	<p>
				5256	The second argument is an integer power, and the first is a value to raise to
				5257	that power.
				5258	</p>
				5259
				5260	<h5>Semantics:</h5>
				5261
				5262	<p>
				5263	This function returns the first value raised to the second power with an
				5264	unspecified sequence of rounding operations.</p>
				5265	</div>
				5266
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5267	<!-- _______________________________________________________________________ -->
				5268	<div class="doc_subsubsection">
				5269	<a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
				5270	</div>
				5271
				5272	<div class="doc_text">
				5273
				5274	<h5>Syntax:</h5>
				5275	<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
				5276	floating point or vector of floating point type. Not all targets support all
				5277	types however.
				5278	<pre>
				5279	declare float @llvm.sin.f32(float %Val)
				5280	declare double @llvm.sin.f64(double %Val)
				5281	declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
				5282	declare fp128 @llvm.sin.f128(fp128 %Val)
				5283	declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
				5284	</pre>
				5285
				5286	<h5>Overview:</h5>
				5287
				5288	<p>
				5289	The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
				5290	</p>
				5291
				5292	<h5>Arguments:</h5>
				5293
				5294	<p>
				5295	The argument and return value are floating point numbers of the same type.
				5296	</p>
				5297
				5298	<h5>Semantics:</h5>
				5299
				5300	<p>
				5301	This function returns the sine of the specified operand, returning the
				5302	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]	5303	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5304	</div>
				5305
				5306	<!-- _______________________________________________________________________ -->
				5307	<div class="doc_subsubsection">
				5308	<a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
				5309	</div>
				5310
				5311	<div class="doc_text">
				5312
				5313	<h5>Syntax:</h5>
				5314	<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
				5315	floating point or vector of floating point type. Not all targets support all
				5316	types however.
				5317	<pre>
				5318	declare float @llvm.cos.f32(float %Val)
				5319	declare double @llvm.cos.f64(double %Val)
				5320	declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
				5321	declare fp128 @llvm.cos.f128(fp128 %Val)
				5322	declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
				5323	</pre>
				5324
				5325	<h5>Overview:</h5>
				5326
				5327	<p>
				5328	The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
				5329	</p>
				5330
				5331	<h5>Arguments:</h5>
				5332
				5333	<p>
				5334	The argument and return value are floating point numbers of the same type.
				5335	</p>
				5336
				5337	<h5>Semantics:</h5>
				5338
				5339	<p>
				5340	This function returns the cosine of the specified operand, returning the
				5341	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]	5342	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5343	</div>
				5344
				5345	<!-- _______________________________________________________________________ -->
				5346	<div class="doc_subsubsection">
				5347	<a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
				5348	</div>
				5349
				5350	<div class="doc_text">
				5351
				5352	<h5>Syntax:</h5>
				5353	<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
				5354	floating point or vector of floating point type. Not all targets support all
				5355	types however.
				5356	<pre>
				5357	declare float @llvm.pow.f32(float %Val, float %Power)
				5358	declare double @llvm.pow.f64(double %Val, double %Power)
				5359	declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
				5360	declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
				5361	declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
				5362	</pre>
				5363
				5364	<h5>Overview:</h5>
				5365
				5366	<p>
				5367	The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
				5368	specified (positive or negative) power.
				5369	</p>
				5370
				5371	<h5>Arguments:</h5>
				5372
				5373	<p>
				5374	The second argument is a floating point power, and the first is a value to
				5375	raise to that power.
				5376	</p>
				5377
				5378	<h5>Semantics:</h5>
				5379
				5380	<p>
				5381	This function returns the first value raised to the second power,
				5382	returning the
				5383	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]	5384	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5385	</div>
				5386
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5387
				5388	<!-- ======================================================================= -->
				5389	<div class="doc_subsection">
				5390	<a name="int_manip">Bit Manipulation Intrinsics</a>
				5391	</div>
				5392
				5393	<div class="doc_text">
				5394	<p>
				5395	LLVM provides intrinsics for a few important bit manipulation operations.
				5396	These allow efficient code generation for some algorithms.
				5397	</p>
				5398
				5399	</div>
				5400
				5401	<!-- _______________________________________________________________________ -->
				5402	<div class="doc_subsubsection">
				5403	<a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
				5404	</div>
				5405
				5406	<div class="doc_text">
				5407
				5408	<h5>Syntax:</h5>
				5409	<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]	5410	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]	5411	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5412	declare i16 @llvm.bswap.i16(i16 <id>)
				5413	declare i32 @llvm.bswap.i32(i32 <id>)
				5414	declare i64 @llvm.bswap.i64(i64 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5415	</pre>
				5416
				5417	<h5>Overview:</h5>
				5418
				5419	<p>
				5420	The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
				5421	values with an even number of bytes (positive multiple of 16 bits). These are
				5422	useful for performing operations on data that is not in the target's native
				5423	byte order.
				5424	</p>
				5425
				5426	<h5>Semantics:</h5>
				5427
				5428	<p>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5429	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]	5430	and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
				5431	intrinsic returns an i32 value that has the four bytes of the input i32
				5432	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]	5433	i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
				5434	<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5435	additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
				5436	</p>
				5437
				5438	</div>
				5439
				5440	<!-- _______________________________________________________________________ -->
				5441	<div class="doc_subsubsection">
				5442	<a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
				5443	</div>
				5444
				5445	<div class="doc_text">
				5446
				5447	<h5>Syntax:</h5>
				5448	<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
				5449	width. Not all targets support all bit widths however.
				5450	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5451	declare i8 @llvm.ctpop.i8 (i8 <src>)
				5452	declare i16 @llvm.ctpop.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5453	declare i32 @llvm.ctpop.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5454	declare i64 @llvm.ctpop.i64(i64 <src>)
				5455	declare i256 @llvm.ctpop.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5456	</pre>
				5457
				5458	<h5>Overview:</h5>
				5459
				5460	<p>
				5461	The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
				5462	value.
				5463	</p>
				5464
				5465	<h5>Arguments:</h5>
				5466
				5467	<p>
				5468	The only argument is the value to be counted. The argument may be of any
				5469	integer type. The return type must match the argument type.
				5470	</p>
				5471
				5472	<h5>Semantics:</h5>
				5473
				5474	<p>
				5475	The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
				5476	</p>
				5477	</div>
				5478
				5479	<!-- _______________________________________________________________________ -->
				5480	<div class="doc_subsubsection">
				5481	<a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
				5482	</div>
				5483
				5484	<div class="doc_text">
				5485
				5486	<h5>Syntax:</h5>
				5487	<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
				5488	integer bit width. Not all targets support all bit widths however.
				5489	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5490	declare i8 @llvm.ctlz.i8 (i8 <src>)
				5491	declare i16 @llvm.ctlz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5492	declare i32 @llvm.ctlz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5493	declare i64 @llvm.ctlz.i64(i64 <src>)
				5494	declare i256 @llvm.ctlz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5495	</pre>
				5496
				5497	<h5>Overview:</h5>
				5498
				5499	<p>
				5500	The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
				5501	leading zeros in a variable.
				5502	</p>
				5503
				5504	<h5>Arguments:</h5>
				5505
				5506	<p>
				5507	The only argument is the value to be counted. The argument may be of any
				5508	integer type. The return type must match the argument type.
				5509	</p>
				5510
				5511	<h5>Semantics:</h5>
				5512
				5513	<p>
				5514	The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
				5515	in a variable. If the src == 0 then the result is the size in bits of the type
				5516	of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
				5517	</p>
				5518	</div>
				5519
				5520
				5521
				5522	<!-- _______________________________________________________________________ -->
				5523	<div class="doc_subsubsection">
				5524	<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
				5525	</div>
				5526
				5527	<div class="doc_text">
				5528
				5529	<h5>Syntax:</h5>
				5530	<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
				5531	integer bit width. Not all targets support all bit widths however.
				5532	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5533	declare i8 @llvm.cttz.i8 (i8 <src>)
				5534	declare i16 @llvm.cttz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5535	declare i32 @llvm.cttz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5536	declare i64 @llvm.cttz.i64(i64 <src>)
				5537	declare i256 @llvm.cttz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5538	</pre>
				5539
				5540	<h5>Overview:</h5>
				5541
				5542	<p>
				5543	The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
				5544	trailing zeros.
				5545	</p>
				5546
				5547	<h5>Arguments:</h5>
				5548
				5549	<p>
				5550	The only argument is the value to be counted. The argument may be of any
				5551	integer type. The return type must match the argument type.
				5552	</p>
				5553
				5554	<h5>Semantics:</h5>
				5555
				5556	<p>
				5557	The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
				5558	in a variable. If the src == 0 then the result is the size in bits of the type
				5559	of src. For example, <tt>llvm.cttz(2) = 1</tt>.
				5560	</p>
				5561	</div>
				5562
				5563	<!-- _______________________________________________________________________ -->
				5564	<div class="doc_subsubsection">
				5565	<a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
				5566	</div>
				5567
				5568	<div class="doc_text">
				5569
				5570	<h5>Syntax:</h5>
				5571	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
				5572	on any integer bit width.
				5573	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5574	declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
				5575	declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5576	</pre>
				5577
				5578	<h5>Overview:</h5>
				5579	<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
				5580	range of bits from an integer value and returns them in the same bit width as
				5581	the original value.</p>
				5582
				5583	<h5>Arguments:</h5>
				5584	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5585	any bit width but they must have the same bit width. The second and third
				5586	arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
				5587
				5588	<h5>Semantics:</h5>
				5589	<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
				5590	of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
				5591	<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
				5592	operates in forward mode.</p>
				5593	<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
				5594	right by <tt>%loBit</tt> bits and then ANDing it with a mask with
				5595	only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
				5596	<ol>
				5597	<li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
				5598	by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
				5599	<li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
				5600	to determine the number of bits to retain.</li>
				5601	<li>A mask of the retained bits is created by shifting a -1 value.</li>
				5602	<li>The mask is ANDed with <tt>%val</tt> to produce the result.
				5603	</ol>
				5604	<p>In reverse mode, a similar computation is made except that the bits are
				5605	returned in the reverse order. So, for example, if <tt>X</tt> has the value
				5606	<tt>i16 0x0ACF (101011001111)</tt> and we apply
				5607	<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
				5608	<tt>i16 0x0026 (000000100110)</tt>.</p>
				5609	</div>
				5610
				5611	<div class="doc_subsubsection">
				5612	<a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
				5613	</div>
				5614
				5615	<div class="doc_text">
				5616
				5617	<h5>Syntax:</h5>
				5618	<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
				5619	on any integer bit width.
				5620	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5621	declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
				5622	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]	5623	</pre>
				5624
				5625	<h5>Overview:</h5>
				5626	<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
				5627	of bits in an integer value with another integer value. It returns the integer
				5628	with the replaced bits.</p>
				5629
				5630	<h5>Arguments:</h5>
				5631	<p>The first argument, <tt>%val</tt> and the result may be integer types of
				5632	any bit width but they must have the same bit width. <tt>%val</tt> is the value
				5633	whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
				5634	integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
				5635	type since they specify only a bit index.</p>
				5636
				5637	<h5>Semantics:</h5>
				5638	<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
				5639	of operation: forwards and reverse. If <tt>%lo</tt> is greater than
				5640	<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
				5641	operates in forward mode.</p>
				5642	<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
				5643	truncating it down to the size of the replacement area or zero extending it
				5644	up to that size.</p>
				5645	<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
				5646	are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
				5647	in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
				5648	to the <tt>%hi</tt>th bit.
				5649	<p>In reverse mode, a similar computation is made except that the bits are
				5650	reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
				5651	<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
				5652	<h5>Examples:</h5>
				5653	<pre>
				5654	llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
				5655	llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
				5656	llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F
				5657	llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
				5658	llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
				5659	</pre>
				5660	</div>
				5661
				5662	<!-- ======================================================================= -->
				5663	<div class="doc_subsection">
				5664	<a name="int_debugger">Debugger Intrinsics</a>
				5665	</div>
				5666
				5667	<div class="doc_text">
				5668	<p>
				5669	The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
				5670	are described in the <a
				5671	href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
				5672	Debugging</a> document.
				5673	</p>
				5674	</div>
				5675
				5676
				5677	<!-- ======================================================================= -->
				5678	<div class="doc_subsection">
				5679	<a name="int_eh">Exception Handling Intrinsics</a>
				5680	</div>
				5681
				5682	<div class="doc_text">
				5683	<p> The LLVM exception handling intrinsics (which all start with
				5684	<tt>llvm.eh.</tt> prefix), are described in the <a
				5685	href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
				5686	Handling</a> document. </p>
				5687	</div>
				5688
				5689	<!-- ======================================================================= -->
				5690	<div class="doc_subsection">
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5691	<a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5692	</div>
				5693
				5694	<div class="doc_text">
				5695	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5696	This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5697	the <tt>nest</tt> attribute, from a function. The result is a callable
				5698	function pointer lacking the nest parameter - the caller does not need
				5699	to provide a value for it. Instead, the value to use is stored in
				5700	advance in a "trampoline", a block of memory usually allocated
				5701	on the stack, which also contains code to splice the nest value into the
				5702	argument list. This is used to implement the GCC nested function address
				5703	extension.
				5704	</p>
				5705	<p>
				5706	For example, if the function is
				5707	<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]	5708	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]	5709	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5710	%tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
				5711	%tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
				5712	%p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8), i8 %nval )
				5713	%fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5714	</pre>
Bill Wendling	e262b4c	2007-09-22 09:23:55 +0000	[diff] [blame]	5715	<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
				5716	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]	5717	</div>
				5718
				5719	<!-- _______________________________________________________________________ -->
				5720	<div class="doc_subsubsection">
				5721	<a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
				5722	</div>
				5723	<div class="doc_text">
				5724	<h5>Syntax:</h5>
				5725	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5726	declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5727	</pre>
				5728	<h5>Overview:</h5>
				5729	<p>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5730	This fills the memory pointed to by <tt>tramp</tt> with code
				5731	and returns a function pointer suitable for executing it.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5732	</p>
				5733	<h5>Arguments:</h5>
				5734	<p>
				5735	The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
				5736	pointers. The <tt>tramp</tt> argument must point to a sufficiently large
				5737	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]	5738	intrinsic. Note that the size and the alignment are target-specific - LLVM
				5739	currently provides no portable way of determining them, so a front-end that
				5740	generates this intrinsic needs to have some target-specific knowledge.
				5741	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]	5742	</p>
				5743	<h5>Semantics:</h5>
				5744	<p>
				5745	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]	5746	dependent code, turning it into a function. A pointer to this function is
				5747	returned, but needs to be bitcast to an
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5748	<a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	5749	before being called. The new function's signature is the same as that of
				5750	<tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
				5751	removed. At most one such <tt>nest</tt> argument is allowed, and it must be
				5752	of pointer type. Calling the new function is equivalent to calling
				5753	<tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
				5754	missing <tt>nest</tt> argument. If, after calling
				5755	<tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
				5756	modified, then the effect of any later call to the returned function pointer is
				5757	undefined.
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	5758	</p>
				5759	</div>
				5760
				5761	<!-- ======================================================================= -->
				5762	<div class="doc_subsection">
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5763	<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
				5764	</div>
				5765
				5766	<div class="doc_text">
				5767	<p>
				5768	These intrinsic functions expand the "universal IR" of LLVM to represent
				5769	hardware constructs for atomic operations and memory synchronization. This
				5770	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]	5771	is aimed at a low enough level to allow any programming models or APIs
				5772	(Application Programming Interfaces) which
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	5773	need atomic behaviors to map cleanly onto it. It is also modeled primarily on
				5774	hardware behavior. Just as hardware provides a "universal IR" for source
				5775	languages, it also provides a starting point for developing a "universal"
				5776	atomic operation and synchronization IR.
				5777	</p>
				5778	<p>
				5779	These do <em>not</em> form an API such as high-level threading libraries,
				5780	software transaction memory systems, atomic primitives, and intrinsic
				5781	functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
				5782	application libraries. The hardware interface provided by LLVM should allow
				5783	a clean implementation of all of these APIs and parallel programming models.
				5784	No one model or paradigm should be selected above others unless the hardware
				5785	itself ubiquitously does so.
				5786
				5787	</p>
				5788	</div>
				5789
				5790	<!-- _______________________________________________________________________ -->
				5791	<div class="doc_subsubsection">
				5792	<a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
				5793	</div>
				5794	<div class="doc_text">
				5795	<h5>Syntax:</h5>
				5796	<pre>
				5797	declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>,
				5798	i1 <device> )
				5799
				5800	</pre>
				5801	<h5>Overview:</h5>
				5802	<p>
				5803	The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
				5804	specific pairs of memory access types.
				5805	</p>
				5806	<h5>Arguments:</h5>
				5807	<p>
				5808	The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
				5809	The first four arguments enables a specific barrier as listed below. The fith
				5810	argument specifies that the barrier applies to io or device or uncached memory.
				5811
				5812	</p>
				5813	<ul>
				5814	<li><tt>ll</tt>: load-load barrier</li>
				5815	<li><tt>ls</tt>: load-store barrier</li>
				5816	<li><tt>sl</tt>: store-load barrier</li>
				5817	<li><tt>ss</tt>: store-store barrier</li>
				5818	<li><tt>device</tt>: barrier applies to device and uncached memory also.
				5819	</ul>
				5820	<h5>Semantics:</h5>
				5821	<p>
				5822	This intrinsic causes the system to enforce some ordering constraints upon
				5823	the loads and stores of the program. This barrier does not indicate
				5824	<em>when</em> any events will occur, it only enforces an <em>order</em> in
				5825	which they occur. For any of the specified pairs of load and store operations
				5826	(f.ex. load-load, or store-load), all of the first operations preceding the
				5827	barrier will complete before any of the second operations succeeding the
				5828	barrier begin. Specifically the semantics for each pairing is as follows:
				5829	</p>
				5830	<ul>
				5831	<li><tt>ll</tt>: All loads before the barrier must complete before any load
				5832	after the barrier begins.</li>
				5833
				5834	<li><tt>ls</tt>: All loads before the barrier must complete before any
				5835	store after the barrier begins.</li>
				5836	<li><tt>ss</tt>: All stores before the barrier must complete before any
				5837	store after the barrier begins.</li>
				5838	<li><tt>sl</tt>: All stores before the barrier must complete before any
				5839	load after the barrier begins.</li>
				5840	</ul>
				5841	<p>
				5842	These semantics are applied with a logical "and" behavior when more than one
				5843	is enabled in a single memory barrier intrinsic.
				5844	</p>
				5845	<p>
				5846	Backends may implement stronger barriers than those requested when they do not
				5847	support as fine grained a barrier as requested. Some architectures do not
				5848	need all types of barriers and on such architectures, these become noops.
				5849	</p>
				5850	<h5>Example:</h5>
				5851	<pre>
				5852	%ptr = malloc i32
				5853	store i32 4, %ptr
				5854
				5855	%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
				5856	call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
				5857	<i>; guarantee the above finishes</i>
				5858	store i32 8, %ptr <i>; before this begins</i>
				5859	</pre>
				5860	</div>
				5861
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5862	<!-- _______________________________________________________________________ -->
				5863	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5864	<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]	5865	</div>
				5866	<div class="doc_text">
				5867	<h5>Syntax:</h5>
				5868	<p>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5869	This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
				5870	any integer bit width and for different address spaces. Not all targets
				5871	support all bit widths however.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5872
				5873	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5874	declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
				5875	declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
				5876	declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
				5877	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]	5878
				5879	</pre>
				5880	<h5>Overview:</h5>
				5881	<p>
				5882	This loads a value in memory and compares it to a given value. If they are
				5883	equal, it stores a new value into the memory.
				5884	</p>
				5885	<h5>Arguments:</h5>
				5886	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5887	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]	5888	well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
				5889	same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
				5890	this integer type. While any bit width integer may be used, targets may only
				5891	lower representations they support in hardware.
				5892
				5893	</p>
				5894	<h5>Semantics:</h5>
				5895	<p>
				5896	This entire intrinsic must be executed atomically. It first loads the value
				5897	in memory pointed to by <tt>ptr</tt> and compares it with the value
				5898	<tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
				5899	loaded value is yielded in all cases. This provides the equivalent of an
				5900	atomic compare-and-swap operation within the SSA framework.
				5901	</p>
				5902	<h5>Examples:</h5>
				5903
				5904	<pre>
				5905	%ptr = malloc i32
				5906	store i32 4, %ptr
				5907
				5908	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5909	%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]	5910	<i>; yields {i32}:result1 = 4</i>
				5911	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5912	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5913
				5914	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5915	%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]	5916	<i>; yields {i32}:result2 = 8</i>
				5917	%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
				5918
				5919	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
				5920	</pre>
				5921	</div>
				5922
				5923	<!-- _______________________________________________________________________ -->
				5924	<div class="doc_subsubsection">
				5925	<a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
				5926	</div>
				5927	<div class="doc_text">
				5928	<h5>Syntax:</h5>
				5929
				5930	<p>
				5931	This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
				5932	integer bit width. Not all targets support all bit widths however.</p>
				5933	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5934	declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
				5935	declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
				5936	declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
				5937	declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5938
				5939	</pre>
				5940	<h5>Overview:</h5>
				5941	<p>
				5942	This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
				5943	the value from memory. It then stores the value in <tt>val</tt> in the memory
				5944	at <tt>ptr</tt>.
				5945	</p>
				5946	<h5>Arguments:</h5>
				5947
				5948	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5949	The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5950	<tt>val</tt> argument and the result must be integers of the same bit width.
				5951	The first argument, <tt>ptr</tt>, must be a pointer to a value of this
				5952	integer type. The targets may only lower integer representations they
				5953	support.
				5954	</p>
				5955	<h5>Semantics:</h5>
				5956	<p>
				5957	This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
				5958	stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
				5959	equivalent of an atomic swap operation within the SSA framework.
				5960
				5961	</p>
				5962	<h5>Examples:</h5>
				5963	<pre>
				5964	%ptr = malloc i32
				5965	store i32 4, %ptr
				5966
				5967	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5968	%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5969	<i>; yields {i32}:result1 = 4</i>
				5970	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				5971	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				5972
				5973	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5974	%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5975	<i>; yields {i32}:result2 = 8</i>
				5976
				5977	%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
				5978	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
				5979	</pre>
				5980	</div>
				5981
				5982	<!-- _______________________________________________________________________ -->
				5983	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5984	<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]	5985
				5986	</div>
				5987	<div class="doc_text">
				5988	<h5>Syntax:</h5>
				5989	<p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	5990	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]	5991	integer bit width. Not all targets support all bit widths however.</p>
				5992	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	5993	declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
				5994	declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
				5995	declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
				5996	declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	5997
				5998	</pre>
				5999	<h5>Overview:</h5>
				6000	<p>
				6001	This intrinsic adds <tt>delta</tt> to the value stored in memory at
				6002	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6003	</p>
				6004	<h5>Arguments:</h5>
				6005	<p>
				6006
				6007	The intrinsic takes two arguments, the first a pointer to an integer value
				6008	and the second an integer value. The result is also an integer value. These
				6009	integer types can have any bit width, but they must all have the same bit
				6010	width. The targets may only lower integer representations they support.
				6011	</p>
				6012	<h5>Semantics:</h5>
				6013	<p>
				6014	This intrinsic does a series of operations atomically. It first loads the
				6015	value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
				6016	to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6017	</p>
				6018
				6019	<h5>Examples:</h5>
				6020	<pre>
				6021	%ptr = malloc i32
				6022	store i32 4, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6023	%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]	6024	<i>; yields {i32}:result1 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6025	%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]	6026	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6027	%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]	6028	<i>; yields {i32}:result3 = 10</i>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6029	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6030	</pre>
				6031	</div>
				6032
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6033	<!-- _______________________________________________________________________ -->
				6034	<div class="doc_subsubsection">
				6035	<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
				6036
				6037	</div>
				6038	<div class="doc_text">
				6039	<h5>Syntax:</h5>
				6040	<p>
				6041	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]	6042	any integer bit width and for different address spaces. Not all targets
				6043	support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6044	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6045	declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
				6046	declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
				6047	declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
				6048	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]	6049
				6050	</pre>
				6051	<h5>Overview:</h5>
				6052	<p>
				6053	This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
				6054	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
				6055	</p>
				6056	<h5>Arguments:</h5>
				6057	<p>
				6058
				6059	The intrinsic takes two arguments, the first a pointer to an integer value
				6060	and the second an integer value. The result is also an integer value. These
				6061	integer types can have any bit width, but they must all have the same bit
				6062	width. The targets may only lower integer representations they support.
				6063	</p>
				6064	<h5>Semantics:</h5>
				6065	<p>
				6066	This intrinsic does a series of operations atomically. It first loads the
				6067	value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
				6068	result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
				6069	</p>
				6070
				6071	<h5>Examples:</h5>
				6072	<pre>
				6073	%ptr = malloc i32
				6074	store i32 8, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6075	%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]	6076	<i>; yields {i32}:result1 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6077	%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]	6078	<i>; yields {i32}:result2 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6079	%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]	6080	<i>; yields {i32}:result3 = 2</i>
				6081	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
				6082	</pre>
				6083	</div>
				6084
				6085	<!-- _______________________________________________________________________ -->
				6086	<div class="doc_subsubsection">
				6087	<a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
				6088	<a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
				6089	<a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
				6090	<a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
				6091
				6092	</div>
				6093	<div class="doc_text">
				6094	<h5>Syntax:</h5>
				6095	<p>
				6096	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
				6097	<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]	6098	<tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
				6099	address spaces. Not all targets support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6100	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6101	declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
				6102	declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
				6103	declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
				6104	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]	6105
				6106	</pre>
				6107
				6108	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6109	declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
				6110	declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
				6111	declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
				6112	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]	6113
				6114	</pre>
				6115
				6116	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6117	declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
				6118	declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
				6119	declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
				6120	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]	6121
				6122	</pre>
				6123
				6124	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6125	declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
				6126	declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
				6127	declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
				6128	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]	6129
				6130	</pre>
				6131	<h5>Overview:</h5>
				6132	<p>
				6133	These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
				6134	the value stored in memory at <tt>ptr</tt>. It yields the original value
				6135	at <tt>ptr</tt>.
				6136	</p>
				6137	<h5>Arguments:</h5>
				6138	<p>
				6139
				6140	These intrinsics take two arguments, the first a pointer to an integer value
				6141	and the second an integer value. The result is also an integer value. These
				6142	integer types can have any bit width, but they must all have the same bit
				6143	width. The targets may only lower integer representations they support.
				6144	</p>
				6145	<h5>Semantics:</h5>
				6146	<p>
				6147	These intrinsics does a series of operations atomically. They first load the
				6148	value stored at <tt>ptr</tt>. They then do the bitwise operation
				6149	<tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
				6150	value stored at <tt>ptr</tt>.
				6151	</p>
				6152
				6153	<h5>Examples:</h5>
				6154	<pre>
				6155	%ptr = malloc i32
				6156	store i32 0x0F0F, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6157	%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]	6158	<i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6159	%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]	6160	<i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6161	%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]	6162	<i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6163	%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]	6164	<i>; yields {i32}:result3 = FF</i>
				6165	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
				6166	</pre>
				6167	</div>
				6168
				6169
				6170	<!-- _______________________________________________________________________ -->
				6171	<div class="doc_subsubsection">
				6172	<a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
				6173	<a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
				6174	<a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
				6175	<a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
				6176
				6177	</div>
				6178	<div class="doc_text">
				6179	<h5>Syntax:</h5>
				6180	<p>
				6181	These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
				6182	<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]	6183	<tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
				6184	address spaces. Not all targets
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6185	support all bit widths however.</p>
				6186	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6187	declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
				6188	declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
				6189	declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
				6190	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]	6191
				6192	</pre>
				6193
				6194	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6195	declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
				6196	declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
				6197	declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
				6198	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]	6199
				6200	</pre>
				6201
				6202	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6203	declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
				6204	declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
				6205	declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
				6206	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]	6207
				6208	</pre>
				6209
				6210	<pre>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6211	declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
				6212	declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
				6213	declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
				6214	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]	6215
				6216	</pre>
				6217	<h5>Overview:</h5>
				6218	<p>
				6219	These intrinsics takes the signed or unsigned minimum or maximum of
				6220	<tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
				6221	original value at <tt>ptr</tt>.
				6222	</p>
				6223	<h5>Arguments:</h5>
				6224	<p>
				6225
				6226	These intrinsics take two arguments, the first a pointer to an integer value
				6227	and the second an integer value. The result is also an integer value. These
				6228	integer types can have any bit width, but they must all have the same bit
				6229	width. The targets may only lower integer representations they support.
				6230	</p>
				6231	<h5>Semantics:</h5>
				6232	<p>
				6233	These intrinsics does a series of operations atomically. They first load the
				6234	value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
				6235	<tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
				6236	the original value stored at <tt>ptr</tt>.
				6237	</p>
				6238
				6239	<h5>Examples:</h5>
				6240	<pre>
				6241	%ptr = malloc i32
				6242	store i32 7, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6243	%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]	6244	<i>; yields {i32}:result0 = 7</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6245	%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]	6246	<i>; yields {i32}:result1 = -2</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6247	%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]	6248	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6249	%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]	6250	<i>; yields {i32}:result3 = 8</i>
				6251	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
				6252	</pre>
				6253	</div>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6254
				6255	<!-- ======================================================================= -->
				6256	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6257	<a name="int_general">General Intrinsics</a>
				6258	</div>
				6259
				6260	<div class="doc_text">
				6261	<p> This class of intrinsics is designed to be generic and has
				6262	no specific purpose. </p>
				6263	</div>
				6264
				6265	<!-- _______________________________________________________________________ -->
				6266	<div class="doc_subsubsection">
				6267	<a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
				6268	</div>
				6269
				6270	<div class="doc_text">
				6271
				6272	<h5>Syntax:</h5>
				6273	<pre>
				6274	declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> )
				6275	</pre>
				6276
				6277	<h5>Overview:</h5>
				6278
				6279	<p>
				6280	The '<tt>llvm.var.annotation</tt>' intrinsic
				6281	</p>
				6282
				6283	<h5>Arguments:</h5>
				6284
				6285	<p>
				6286	The first argument is a pointer to a value, the second is a pointer to a
				6287	global string, the third is a pointer to a global string which is the source
				6288	file name, and the last argument is the line number.
				6289	</p>
				6290
				6291	<h5>Semantics:</h5>
				6292
				6293	<p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6294	This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6295	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]	6296	annotations. These have no other defined use, they are ignored by code
				6297	generation and optimization.
				6298	</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6299	</div>
				6300
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6301	<!-- _______________________________________________________________________ -->
				6302	<div class="doc_subsubsection">
Tanya Lattner	c9869b1	2007-09-21 23:57:59 +0000	[diff] [blame]	6303	<a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6304	</div>
				6305
				6306	<div class="doc_text">
				6307
				6308	<h5>Syntax:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6309	<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
				6310	any integer bit width.
				6311	</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6312	<pre>
Tanya Lattner	09161fe	2007-09-22 00:03:01 +0000	[diff] [blame]	6313	declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
				6314	declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
				6315	declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> )
				6316	declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> )
				6317	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]	6318	</pre>
				6319
				6320	<h5>Overview:</h5>
Tanya Lattner	e545be7	2007-09-21 23:56:27 +0000	[diff] [blame]	6321
				6322	<p>
				6323	The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6324	</p>
				6325
				6326	<h5>Arguments:</h5>
				6327
				6328	<p>
				6329	The first argument is an integer value (result of some expression),
				6330	the second is a pointer to a global string, the third is a pointer to a global
				6331	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]	6332	It returns the value of the first argument.
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6333	</p>
				6334
				6335	<h5>Semantics:</h5>
				6336
				6337	<p>
				6338	This intrinsic allows annotations to be put on arbitrary expressions
				6339	with arbitrary strings. This can be useful for special purpose optimizations
				6340	that want to look for these annotations. These have no other defined use, they
				6341	are ignored by code generation and optimization.
				6342	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6343
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6344	<!-- _______________________________________________________________________ -->
				6345	<div class="doc_subsubsection">
				6346	<a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
				6347	</div>
				6348
				6349	<div class="doc_text">
				6350
				6351	<h5>Syntax:</h5>
				6352	<pre>
				6353	declare void @llvm.trap()
				6354	</pre>
				6355
				6356	<h5>Overview:</h5>
				6357
				6358	<p>
				6359	The '<tt>llvm.trap</tt>' intrinsic
				6360	</p>
				6361
				6362	<h5>Arguments:</h5>
				6363
				6364	<p>
				6365	None
				6366	</p>
				6367
				6368	<h5>Semantics:</h5>
				6369
				6370	<p>
				6371	This intrinsics is lowered to the target dependent trap instruction. If the
				6372	target does not have a trap instruction, this intrinsic will be lowered to the
				6373	call of the abort() function.
				6374	</p>
				6375	</div>
				6376
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6377	<!-- *********************************************************************** -->
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				6385	<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
				6386	<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
				6387	Last modified: $Date$
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