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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 2f7a8b091aa31c2dd6e6ebb6929501d6b430f9c4 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194 </ol>
195 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]196</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]197
198<div class="doc_author">
199 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
200 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]201</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204<div class="doc_section"> <a name="abstract">Abstract </a></div>
205<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]207<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208<p>This document is a reference manual for the LLVM assembly language.
209LLVM is an SSA based representation that provides type safety,
210low-level operations, flexibility, and the capability of representing
211'all' high-level languages cleanly. It is the common code
212representation used throughout all phases of the LLVM compilation
213strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]214</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217<div class="doc_section"> <a name="introduction">Introduction</a> </div>
218<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]220<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]221
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<p>The LLVM code representation is designed to be used in three
223different forms: as an in-memory compiler IR, as an on-disk bytecode
224representation (suitable for fast loading by a Just-In-Time compiler),
225and as a human readable assembly language representation. This allows
226LLVM to provide a powerful intermediate representation for efficient
227compiler transformations and analysis, while providing a natural means
228to debug and visualize the transformations. The three different forms
229of LLVM are all equivalent. This document describes the human readable
230representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]231
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]232<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]233while being expressive, typed, and extensible at the same time. It
234aims to be a "universal IR" of sorts, by being at a low enough level
235that high-level ideas may be cleanly mapped to it (similar to how
236microprocessors are "universal IR's", allowing many source languages to
237be mapped to them). By providing type information, LLVM can be used as
238the target of optimizations: for example, through pointer analysis, it
239can be proven that a C automatic variable is never accessed outside of
240the current function... allowing it to be promoted to a simple SSA
241value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]245<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]247
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]248<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]250<p>It is important to note that this document describes 'well formed'
251LLVM assembly language. There is a difference between what the parser
252accepts and what is considered 'well formed'. For example, the
253following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]255<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]256<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]257%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]258</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]259</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]260
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]261<p>...because the definition of <tt>%x</tt> does not dominate all of
262its uses. The LLVM infrastructure provides a verification pass that may
263be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]264automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]265the optimizer before it outputs bytecode. The violations pointed out
266by the verifier pass indicate bugs in transformation passes or input to
267the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]268</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]269
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]270<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]271
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]272<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]273<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]274<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]275
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]276<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]277
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]278<p>LLVM uses three different forms of identifiers, for different
279purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]280
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]281<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]282 <li>Named values are represented as a string of characters with a '%' prefix.
283 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
284 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
285 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]286 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]287 in a name.</li>
288
289 <li>Unnamed values are represented as an unsigned numeric value with a '%'
290 prefix. For example, %12, %2, %44.</li>
291
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]292 <li>Constants, which are described in a <a href="#constants">section about
293 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]294</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]295
296<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
297don't need to worry about name clashes with reserved words, and the set of
298reserved words may be expanded in the future without penalty. Additionally,
299unnamed identifiers allow a compiler to quickly come up with a temporary
300variable without having to avoid symbol table conflicts.</p>
301
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]302<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]303languages. There are keywords for different opcodes
304('<tt><a href="#i_add">add</a></tt>',
305 '<tt><a href="#i_bitcast">bitcast</a></tt>',
306 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]307href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]308and others. These reserved words cannot conflict with variable names, because
309none of them start with a '%' character.</p>
310
311<p>Here is an example of LLVM code to multiply the integer variable
312'<tt>%X</tt>' by 8:</p>
313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]314<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]316<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]318%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]319</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]320</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]322<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]323
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]324<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]326%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]327</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]328</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]330<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]331
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]332<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]333<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]334<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
335<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
336%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]337</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]338</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]339
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]340<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
341important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]343<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344
345 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
346 line.</li>
347
348 <li>Unnamed temporaries are created when the result of a computation is not
349 assigned to a named value.</li>
350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]351 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]352
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]353</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]354
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]355<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]356demonstrating instructions, we will follow an instruction with a comment that
357defines the type and name of value produced. Comments are shown in italic
358text.</p>
359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]360</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]361
362<!-- *********************************************************************** -->
363<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
364<!-- *********************************************************************** -->
365
366<!-- ======================================================================= -->
367<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
368</div>
369
370<div class="doc_text">
371
372<p>LLVM programs are composed of "Module"s, each of which is a
373translation unit of the input programs. Each module consists of
374functions, global variables, and symbol table entries. Modules may be
375combined together with the LLVM linker, which merges function (and
376global variable) definitions, resolves forward declarations, and merges
377symbol table entries. Here is an example of the "hello world" module:</p>
378
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]379<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]380<pre><i>; Declare the string constant as a global constant...</i>
381<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]382 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]383
384<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]385<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386
387<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]388define i32 %main() { <i>; i32()* </i>
389 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]390 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]391 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]392
393 <i>; Call puts function to write out the string to stdout...</i>
394 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]395 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]396 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]397 href="#i_ret">ret</a> i32 0<br>}<br>
398</pre>
399</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]400
401<p>This example is made up of a <a href="#globalvars">global variable</a>
402named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
403function, and a <a href="#functionstructure">function definition</a>
404for "<tt>main</tt>".</p>
405
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]406<p>In general, a module is made up of a list of global values,
407where both functions and global variables are global values. Global values are
408represented by a pointer to a memory location (in this case, a pointer to an
409array of char, and a pointer to a function), and have one of the following <a
410href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]411
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412</div>
413
414<!-- ======================================================================= -->
415<div class="doc_subsection">
416 <a name="linkage">Linkage Types</a>
417</div>
418
419<div class="doc_text">
420
421<p>
422All Global Variables and Functions have one of the following types of linkage:
423</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]424
425<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]427 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428
429 <dd>Global values with internal linkage are only directly accessible by
430 objects in the current module. In particular, linking code into a module with
431 an internal global value may cause the internal to be renamed as necessary to
432 avoid collisions. Because the symbol is internal to the module, all
433 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]434 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]435 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]437 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]439 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
440 the same name when linkage occurs. This is typically used to implement
441 inline functions, templates, or other code which must be generated in each
442 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
443 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]444 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]446 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
448 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
449 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]450 used for globals that may be emitted in multiple translation units, but that
451 are not guaranteed to be emitted into every translation unit that uses them.
452 One example of this are common globals in C, such as "<tt>int X;</tt>" at
453 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]454 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]456 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457
458 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
459 pointer to array type. When two global variables with appending linkage are
460 linked together, the two global arrays are appended together. This is the
461 LLVM, typesafe, equivalent of having the system linker append together
462 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]463 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]465 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
466 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
467 until linked, if not linked, the symbol becomes null instead of being an
468 undefined reference.
469 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]470
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
473 <dd>If none of the above identifiers are used, the global is externally
474 visible, meaning that it participates in linkage and can be used to resolve
475 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]477</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]478
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]479 <p>
480 The next two types of linkage are targeted for Microsoft Windows platform
481 only. They are designed to support importing (exporting) symbols from (to)
482 DLLs.
483 </p>
484
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]485 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]486 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
487
488 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
489 or variable via a global pointer to a pointer that is set up by the DLL
490 exporting the symbol. On Microsoft Windows targets, the pointer name is
491 formed by combining <code>_imp__</code> and the function or variable name.
492 </dd>
493
494 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
495
496 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
497 pointer to a pointer in a DLL, so that it can be referenced with the
498 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
499 name is formed by combining <code>_imp__</code> and the function or variable
500 name.
501 </dd>
502
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]503</dl>
504
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]505<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]506variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
507variable and was linked with this one, one of the two would be renamed,
508preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
509external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]510outside of the current module.</p>
511<p>It is illegal for a function <i>declaration</i>
512to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]513or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]514<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
515linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]516</div>
517
518<!-- ======================================================================= -->
519<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]520 <a name="callingconv">Calling Conventions</a>
521</div>
522
523<div class="doc_text">
524
525<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
526and <a href="#i_invoke">invokes</a> can all have an optional calling convention
527specified for the call. The calling convention of any pair of dynamic
528caller/callee must match, or the behavior of the program is undefined. The
529following calling conventions are supported by LLVM, and more may be added in
530the future:</p>
531
532<dl>
533 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
534
535 <dd>This calling convention (the default if no other calling convention is
536 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]537 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]538 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]539 </dd>
540
541 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
542
543 <dd>This calling convention attempts to make calls as fast as possible
544 (e.g. by passing things in registers). This calling convention allows the
545 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]546 without having to conform to an externally specified ABI. Implementations of
547 this convention should allow arbitrary tail call optimization to be supported.
548 This calling convention does not support varargs and requires the prototype of
549 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]550 </dd>
551
552 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
553
554 <dd>This calling convention attempts to make code in the caller as efficient
555 as possible under the assumption that the call is not commonly executed. As
556 such, these calls often preserve all registers so that the call does not break
557 any live ranges in the caller side. This calling convention does not support
558 varargs and requires the prototype of all callees to exactly match the
559 prototype of the function definition.
560 </dd>
561
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]562 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]563
564 <dd>Any calling convention may be specified by number, allowing
565 target-specific calling conventions to be used. Target specific calling
566 conventions start at 64.
567 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]568</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]569
570<p>More calling conventions can be added/defined on an as-needed basis, to
571support pascal conventions or any other well-known target-independent
572convention.</p>
573
574</div>
575
576<!-- ======================================================================= -->
577<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]578 <a name="visibility">Visibility Styles</a>
579</div>
580
581<div class="doc_text">
582
583<p>
584All Global Variables and Functions have one of the following visibility styles:
585</p>
586
587<dl>
588 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
589
590 <dd>On ELF, default visibility means that the declaration is visible to other
591 modules and, in shared libraries, means that the declared entity may be
592 overridden. On Darwin, default visibility means that the declaration is
593 visible to other modules. Default visibility corresponds to "external
594 linkage" in the language.
595 </dd>
596
597 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
598
599 <dd>Two declarations of an object with hidden visibility refer to the same
600 object if they are in the same shared object. Usually, hidden visibility
601 indicates that the symbol will not be placed into the dynamic symbol table,
602 so no other module (executable or shared library) can reference it
603 directly.
604 </dd>
605
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]606 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
607
608 <dd>On ELF, protected visibility indicates that the symbol will be placed in
609 the dynamic symbol table, but that references within the defining module will
610 bind to the local symbol. That is, the symbol cannot be overridden by another
611 module.
612 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]613</dl>
614
615</div>
616
617<!-- ======================================================================= -->
618<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]619 <a name="globalvars">Global Variables</a>
620</div>
621
622<div class="doc_text">
623
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]624<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]625instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]626an explicit section to be placed in, and may have an optional explicit alignment
627specified. A variable may be defined as "thread_local", which means that it
628will not be shared by threads (each thread will have a separated copy of the
629variable). A variable may be defined as a global "constant," which indicates
630that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]631optimization, allowing the global data to be placed in the read-only section of
632an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]633cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]634
635<p>
636LLVM explicitly allows <em>declarations</em> of global variables to be marked
637constant, even if the final definition of the global is not. This capability
638can be used to enable slightly better optimization of the program, but requires
639the language definition to guarantee that optimizations based on the
640'constantness' are valid for the translation units that do not include the
641definition.
642</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]643
644<p>As SSA values, global variables define pointer values that are in
645scope (i.e. they dominate) all basic blocks in the program. Global
646variables always define a pointer to their "content" type because they
647describe a region of memory, and all memory objects in LLVM are
648accessed through pointers.</p>
649
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]650<p>LLVM allows an explicit section to be specified for globals. If the target
651supports it, it will emit globals to the section specified.</p>
652
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]653<p>An explicit alignment may be specified for a global. If not present, or if
654the alignment is set to zero, the alignment of the global is set by the target
655to whatever it feels convenient. If an explicit alignment is specified, the
656global is forced to have at least that much alignment. All alignments must be
657a power of 2.</p>
658
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]659<p>For example, the following defines a global with an initializer, section,
660 and alignment:</p>
661
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]662<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]663<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]664%G = constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]665</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]666</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]667
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]668</div>
669
670
671<!-- ======================================================================= -->
672<div class="doc_subsection">
673 <a name="functionstructure">Functions</a>
674</div>
675
676<div class="doc_text">
677
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]678<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
679an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]680<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]681<a href="#callingconv">calling convention</a>, a return type, an optional
682<a href="#paramattrs">parameter attribute</a> for the return type, a function
683name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]684<a href="#paramattrs">parameter attributes</a>), an optional section, an
685optional alignment, an opening curly brace, a list of basic blocks, and a
686closing curly brace.
687
688LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
689optional <a href="#linkage">linkage type</a>, an optional
690<a href="#visibility">visibility style</a>, an optional
691<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]692<a href="#paramattrs">parameter attribute</a> for the return type, a function
693name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]694
695<p>A function definition contains a list of basic blocks, forming the CFG for
696the function. Each basic block may optionally start with a label (giving the
697basic block a symbol table entry), contains a list of instructions, and ends
698with a <a href="#terminators">terminator</a> instruction (such as a branch or
699function return).</p>
700
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]701<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]702executed on entrance to the function, and it is not allowed to have predecessor
703basic blocks (i.e. there can not be any branches to the entry block of a
704function). Because the block can have no predecessors, it also cannot have any
705<a href="#i_phi">PHI nodes</a>.</p>
706
707<p>LLVM functions are identified by their name and type signature. Hence, two
708functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]709considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]710appropriately.</p>
711
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]712<p>LLVM allows an explicit section to be specified for functions. If the target
713supports it, it will emit functions to the section specified.</p>
714
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]715<p>An explicit alignment may be specified for a function. If not present, or if
716the alignment is set to zero, the alignment of the function is set by the target
717to whatever it feels convenient. If an explicit alignment is specified, the
718function is forced to have at least that much alignment. All alignments must be
719a power of 2.</p>
720
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]721</div>
722
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]723
724<!-- ======================================================================= -->
725<div class="doc_subsection">
726 <a name="aliasstructure">Aliases</a>
727</div>
728<div class="doc_text">
729 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]730 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]731 optional <a href="#linkage">linkage type</a>, and an
732 optional <a href="#visibility">visibility style</a>.</p>
733
734 <h5>Syntax:</h5>
735
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]736<div class="doc_code">
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]737 <pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]738@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]739 </pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]740</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]741
742</div>
743
744
745
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]746<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]747<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
748<div class="doc_text">
749 <p>The return type and each parameter of a function type may have a set of
750 <i>parameter attributes</i> associated with them. Parameter attributes are
751 used to communicate additional information about the result or parameters of
752 a function. Parameter attributes are considered to be part of the function
753 type so two functions types that differ only by the parameter attributes
754 are different function types.</p>
755
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]756 <p>Parameter attributes are simple keywords that follow the type specified. If
757 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]758 example:</p>
759
760<div class="doc_code">
761<pre>
762%someFunc = i16 (i8 sext %someParam) zext
763%someFunc = i16 (i8 zext %someParam) zext
764</pre>
765</div>
766
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]767 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]768 a different attribute (sext in the first one, zext in the second). Also note
769 that the attribute for the function result (zext) comes immediately after the
770 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]771
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]772 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]773 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]774 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]775 <dd>This indicates that the parameter should be zero extended just before
776 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]777 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]778 <dd>This indicates that the parameter should be sign extended just before
779 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]780 <dt><tt>inreg</tt></dt>
781 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]782 possible) during assembling function call. Support for this attribute is
783 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]784 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]785 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]786 that is the return value of the function in the source program.</dd>
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]787 <dt><tt>noreturn</tt></dt>
788 <dd>This function attribute indicates that the function never returns. This
789 indicates to LLVM that every call to this function should be treated as if
790 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]791 <dt><tt>nounwind</tt></dt>
792 <dd>This function attribute indicates that the function type does not use
793 the unwind instruction and does not allow stack unwinding to propagate
794 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]795 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]796
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]797</div>
798
799<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]800<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]801 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]802</div>
803
804<div class="doc_text">
805<p>
806Modules may contain "module-level inline asm" blocks, which corresponds to the
807GCC "file scope inline asm" blocks. These blocks are internally concatenated by
808LLVM and treated as a single unit, but may be separated in the .ll file if
809desired. The syntax is very simple:
810</p>
811
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]812<div class="doc_code">
813<pre>
814module asm "inline asm code goes here"
815module asm "more can go here"
816</pre>
817</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]818
819<p>The strings can contain any character by escaping non-printable characters.
820 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
821 for the number.
822</p>
823
824<p>
825 The inline asm code is simply printed to the machine code .s file when
826 assembly code is generated.
827</p>
828</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]829
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]830<!-- ======================================================================= -->
831<div class="doc_subsection">
832 <a name="datalayout">Data Layout</a>
833</div>
834
835<div class="doc_text">
836<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]837data is to be laid out in memory. The syntax for the data layout is simply:</p>
838<pre> target datalayout = "<i>layout specification</i>"</pre>
839<p>The <i>layout specification</i> consists of a list of specifications
840separated by the minus sign character ('-'). Each specification starts with a
841letter and may include other information after the letter to define some
842aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]843<dl>
844 <dt><tt>E</tt></dt>
845 <dd>Specifies that the target lays out data in big-endian form. That is, the
846 bits with the most significance have the lowest address location.</dd>
847 <dt><tt>e</tt></dt>
848 <dd>Specifies that hte target lays out data in little-endian form. That is,
849 the bits with the least significance have the lowest address location.</dd>
850 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
851 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
852 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
853 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
854 too.</dd>
855 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
856 <dd>This specifies the alignment for an integer type of a given bit
857 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
858 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
859 <dd>This specifies the alignment for a vector type of a given bit
860 <i>size</i>.</dd>
861 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
862 <dd>This specifies the alignment for a floating point type of a given bit
863 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
864 (double).</dd>
865 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
866 <dd>This specifies the alignment for an aggregate type of a given bit
867 <i>size</i>.</dd>
868</dl>
869<p>When constructing the data layout for a given target, LLVM starts with a
870default set of specifications which are then (possibly) overriden by the
871specifications in the <tt>datalayout</tt> keyword. The default specifications
872are given in this list:</p>
873<ul>
874 <li><tt>E</tt> - big endian</li>
875 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
876 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
877 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
878 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
879 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
880 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
881 alignment of 64-bits</li>
882 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
883 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
884 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
885 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
886 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
887</ul>
888<p>When llvm is determining the alignment for a given type, it uses the
889following rules:
890<ol>
891 <li>If the type sought is an exact match for one of the specifications, that
892 specification is used.</li>
893 <li>If no match is found, and the type sought is an integer type, then the
894 smallest integer type that is larger than the bitwidth of the sought type is
895 used. If none of the specifications are larger than the bitwidth then the the
896 largest integer type is used. For example, given the default specifications
897 above, the i7 type will use the alignment of i8 (next largest) while both
898 i65 and i256 will use the alignment of i64 (largest specified).</li>
899 <li>If no match is found, and the type sought is a vector type, then the
900 largest vector type that is smaller than the sought vector type will be used
901 as a fall back. This happens because <128 x double> can be implemented in
902 terms of 64 <2 x double>, for example.</li>
903</ol>
904</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]906<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]907<div class="doc_section"> <a name="typesystem">Type System</a> </div>
908<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]910<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]911
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]912<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]913intermediate representation. Being typed enables a number of
914optimizations to be performed on the IR directly, without having to do
915extra analyses on the side before the transformation. A strong type
916system makes it easier to read the generated code and enables novel
917analyses and transformations that are not feasible to perform on normal
918three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]919
920</div>
921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]922<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]923<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]924<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]925<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]926system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]927
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]928<table class="layout">
929 <tr class="layout">
930 <td class="left">
931 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]932 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]933 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]934 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]935 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]936 </tbody>
937 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]938 </td>
939 <td class="right">
940 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]941 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]942 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]943 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]944 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]945 </tbody>
946 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]947 </td>
948 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]949</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]950</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]952<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]953<div class="doc_subsubsection"> <a name="t_classifications">Type
954Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]955<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]956<p>These different primitive types fall into a few useful
957classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]958
959<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]960 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]961 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]962 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]963 <td><a name="t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]964 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]965 </tr>
966 <tr>
967 <td><a name="t_floating">floating point</a></td>
968 <td><tt>float, double</tt></td>
969 </tr>
970 <tr>
971 <td><a name="t_firstclass">first class</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]972 <td><tt>i1, ..., float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]973 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]974 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]975 </tr>
976 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]977</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]978
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]979<p>The <a href="#t_firstclass">first class</a> types are perhaps the
980most important. Values of these types are the only ones which can be
981produced by instructions, passed as arguments, or used as operands to
982instructions. This means that all structures and arrays must be
983manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]984</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]985
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]986<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]987<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]988
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]989<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]990
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]991<p>The real power in LLVM comes from the derived types in the system.
992This is what allows a programmer to represent arrays, functions,
993pointers, and other useful types. Note that these derived types may be
994recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]995
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]996</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]997
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]998<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]999<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1000
1001<div class="doc_text">
1002
1003<h5>Overview:</h5>
1004<p>The integer type is a very simple derived type that simply specifies an
1005arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10062^23-1 (about 8 million) can be specified.</p>
1007
1008<h5>Syntax:</h5>
1009
1010<pre>
1011 iN
1012</pre>
1013
1014<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1015value.</p>
1016
1017<h5>Examples:</h5>
1018<table class="layout">
1019 <tr class="layout">
1020 <td class="left">
1021 <tt>i1</tt><br/>
1022 <tt>i4</tt><br/>
1023 <tt>i8</tt><br/>
1024 <tt>i16</tt><br/>
1025 <tt>i32</tt><br/>
1026 <tt>i42</tt><br/>
1027 <tt>i64</tt><br/>
1028 <tt>i1942652</tt><br/>
1029 </td>
1030 <td class="left">
1031 A boolean integer of 1 bit<br/>
1032 A nibble sized integer of 4 bits.<br/>
1033 A byte sized integer of 8 bits.<br/>
1034 A half word sized integer of 16 bits.<br/>
1035 A word sized integer of 32 bits.<br/>
1036 An integer whose bit width is the answer. <br/>
1037 A double word sized integer of 64 bits.<br/>
1038 A really big integer of over 1 million bits.<br/>
1039 </td>
1040 </tr>
1041</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1042</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1043
1044<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1045<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1046
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1047<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1048
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1049<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1050
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1051<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1052sequentially in memory. The array type requires a size (number of
1053elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1054
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1055<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1056
1057<pre>
1058 [&lt;# elements&gt; x &lt;elementtype&gt;]
1059</pre>
1060
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1061<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1062be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1063
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1064<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1065<table class="layout">
1066 <tr class="layout">
1067 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1068 <tt>[40 x i32 ]</tt><br/>
1069 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1070 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1071 </td>
1072 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1073 Array of 40 32-bit integer values.<br/>
1074 Array of 41 32-bit integer values.<br/>
1075 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1076 </td>
1077 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1078</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1079<p>Here are some examples of multidimensional arrays:</p>
1080<table class="layout">
1081 <tr class="layout">
1082 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1083 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1084 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1085 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1086 </td>
1087 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1088 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1089 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1090 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1091 </td>
1092 </tr>
1093</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1094
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1095<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1096length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1097LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1098As a special case, however, zero length arrays are recognized to be variable
1099length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1100type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1101
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1102</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1103
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1104<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1105<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1106<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1107<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1108<p>The function type can be thought of as a function signature. It
1109consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1110Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1111(which are structures of pointers to functions), for indirect function
1112calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1113<p>
1114The return type of a function type cannot be an aggregate type.
1115</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1116<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1117<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1118<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]1119specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1120which indicates that the function takes a variable number of arguments.
1121Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1122 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1123<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1124<table class="layout">
1125 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1126 <td class="left"><tt>i32 (i32)</tt></td>
1127 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1128 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1129 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1130 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1131 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1132 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1133 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1134 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1135 <tt>float</tt>.
1136 </td>
1137 </tr><tr class="layout">
1138 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1139 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1140 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1141 which returns an integer. This is the signature for <tt>printf</tt> in
1142 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1143 </td>
1144 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1145</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1146
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1147</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1148<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1149<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1150<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1151<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1152<p>The structure type is used to represent a collection of data members
1153together in memory. The packing of the field types is defined to match
1154the ABI of the underlying processor. The elements of a structure may
1155be any type that has a size.</p>
1156<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1157and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1158field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1159instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1160<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1161<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1162<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1163<table class="layout">
1164 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1165 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1166 <td class="left">A triple of three <tt>i32</tt> values</td>
1167 </tr><tr class="layout">
1168 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1169 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1170 second element is a <a href="#t_pointer">pointer</a> to a
1171 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1172 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1173 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1174</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1175</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1176
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1177<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1178<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1179</div>
1180<div class="doc_text">
1181<h5>Overview:</h5>
1182<p>The packed structure type is used to represent a collection of data members
1183together in memory. There is no padding between fields. Further, the alignment
1184of a packed structure is 1 byte. The elements of a packed structure may
1185be any type that has a size.</p>
1186<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1187and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1188field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1189instruction.</p>
1190<h5>Syntax:</h5>
1191<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1192<h5>Examples:</h5>
1193<table class="layout">
1194 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1195 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1196 <td class="left">A triple of three <tt>i32</tt> values</td>
1197 </tr><tr class="layout">
1198 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1199 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1200 second element is a <a href="#t_pointer">pointer</a> to a
1201 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1202 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1203 </tr>
1204</table>
1205</div>
1206
1207<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1208<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1209<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1210<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1211<p>As in many languages, the pointer type represents a pointer or
1212reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1213<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1214<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1215<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1216<table class="layout">
1217 <tr class="layout">
1218 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1219 <tt>[4x i32]*</tt><br/>
1220 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1221 </td>
1222 <td class="left">
1223 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1224 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1225 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1226 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1227 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1228 </td>
1229 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1230</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1231</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1232
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1233<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1234<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1235<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1236
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1237<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1238
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1239<p>A vector type is a simple derived type that represents a vector
1240of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1241are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1242A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1243elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1244of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1245considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1246
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1247<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1248
1249<pre>
1250 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1251</pre>
1252
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1253<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1254be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1255
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1256<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1257
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1258<table class="layout">
1259 <tr class="layout">
1260 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1261 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1262 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1263 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1264 </td>
1265 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1266 Vector of 4 32-bit integer values.<br/>
1267 Vector of 8 floating-point values.<br/>
1268 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1269 </td>
1270 </tr>
1271</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1272</div>
1273
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1274<!-- _______________________________________________________________________ -->
1275<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1276<div class="doc_text">
1277
1278<h5>Overview:</h5>
1279
1280<p>Opaque types are used to represent unknown types in the system. This
1281corresponds (for example) to the C notion of a foward declared structure type.
1282In LLVM, opaque types can eventually be resolved to any type (not just a
1283structure type).</p>
1284
1285<h5>Syntax:</h5>
1286
1287<pre>
1288 opaque
1289</pre>
1290
1291<h5>Examples:</h5>
1292
1293<table class="layout">
1294 <tr class="layout">
1295 <td class="left">
1296 <tt>opaque</tt>
1297 </td>
1298 <td class="left">
1299 An opaque type.<br/>
1300 </td>
1301 </tr>
1302</table>
1303</div>
1304
1305
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1306<!-- *********************************************************************** -->
1307<div class="doc_section"> <a name="constants">Constants</a> </div>
1308<!-- *********************************************************************** -->
1309
1310<div class="doc_text">
1311
1312<p>LLVM has several different basic types of constants. This section describes
1313them all and their syntax.</p>
1314
1315</div>
1316
1317<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1318<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1319
1320<div class="doc_text">
1321
1322<dl>
1323 <dt><b>Boolean constants</b></dt>
1324
1325 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1326 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1327 </dd>
1328
1329 <dt><b>Integer constants</b></dt>
1330
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1331 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1332 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1333 integer types.
1334 </dd>
1335
1336 <dt><b>Floating point constants</b></dt>
1337
1338 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1339 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1340 notation (see below). Floating point constants must have a <a
1341 href="#t_floating">floating point</a> type. </dd>
1342
1343 <dt><b>Null pointer constants</b></dt>
1344
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1345 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1346 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1347
1348</dl>
1349
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1350<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1351of floating point constants. For example, the form '<tt>double
13520x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13534.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1354(and the only time that they are generated by the disassembler) is when a
1355floating point constant must be emitted but it cannot be represented as a
1356decimal floating point number. For example, NaN's, infinities, and other
1357special values are represented in their IEEE hexadecimal format so that
1358assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1359
1360</div>
1361
1362<!-- ======================================================================= -->
1363<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1364</div>
1365
1366<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1367<p>Aggregate constants arise from aggregation of simple constants
1368and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1369
1370<dl>
1371 <dt><b>Structure constants</b></dt>
1372
1373 <dd>Structure constants are represented with notation similar to structure
1374 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1375 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1376 where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1377 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1378 types of elements must match those specified by the type.
1379 </dd>
1380
1381 <dt><b>Array constants</b></dt>
1382
1383 <dd>Array constants are represented with notation similar to array type
1384 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1385 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1386 constants must have <a href="#t_array">array type</a>, and the number and
1387 types of elements must match those specified by the type.
1388 </dd>
1389
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1390 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1391
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1392 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1393 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1394 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1395 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1396 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1397 match those specified by the type.
1398 </dd>
1399
1400 <dt><b>Zero initialization</b></dt>
1401
1402 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1403 value to zero of <em>any</em> type, including scalar and aggregate types.
1404 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1405 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1406 initializers.
1407 </dd>
1408</dl>
1409
1410</div>
1411
1412<!-- ======================================================================= -->
1413<div class="doc_subsection">
1414 <a name="globalconstants">Global Variable and Function Addresses</a>
1415</div>
1416
1417<div class="doc_text">
1418
1419<p>The addresses of <a href="#globalvars">global variables</a> and <a
1420href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1421constants. These constants are explicitly referenced when the <a
1422href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1423href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1424file:</p>
1425
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1426<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1428%X = global i32 17
1429%Y = global i32 42
1430%Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1431</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1432</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1433
1434</div>
1435
1436<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1437<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1438<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1439 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1440 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1441 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1442
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1443 <p>Undefined values indicate to the compiler that the program is well defined
1444 no matter what value is used, giving the compiler more freedom to optimize.
1445 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1446</div>
1447
1448<!-- ======================================================================= -->
1449<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1450</div>
1451
1452<div class="doc_text">
1453
1454<p>Constant expressions are used to allow expressions involving other constants
1455to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1456href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1457that does not have side effects (e.g. load and call are not supported). The
1458following is the syntax for constant expressions:</p>
1459
1460<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1461 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1462 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1463 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1464
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1465 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1466 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1467 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1468
1469 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1470 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1471 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1472
1473 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1474 <dd>Truncate a floating point constant to another floating point type. The
1475 size of CST must be larger than the size of TYPE. Both types must be
1476 floating point.</dd>
1477
1478 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1479 <dd>Floating point extend a constant to another type. The size of CST must be
1480 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1481
1482 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1483 <dd>Convert a floating point constant to the corresponding unsigned integer
1484 constant. TYPE must be an integer type. CST must be floating point. If the
1485 value won't fit in the integer type, the results are undefined.</dd>
1486
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1487 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1488 <dd>Convert a floating point constant to the corresponding signed integer
1489 constant. TYPE must be an integer type. CST must be floating point. If the
1490 value won't fit in the integer type, the results are undefined.</dd>
1491
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1492 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1493 <dd>Convert an unsigned integer constant to the corresponding floating point
1494 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1495 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1496
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1497 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1498 <dd>Convert a signed integer constant to the corresponding floating point
1499 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1500 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1501
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1502 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1503 <dd>Convert a pointer typed constant to the corresponding integer constant
1504 TYPE must be an integer type. CST must be of pointer type. The CST value is
1505 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1506
1507 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1508 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1509 pointer type. CST must be of integer type. The CST value is zero extended,
1510 truncated, or unchanged to make it fit in a pointer size. This one is
1511 <i>really</i> dangerous!</dd>
1512
1513 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1514 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1515 identical (same number of bits). The conversion is done as if the CST value
1516 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1517 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1518 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1519 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1520 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1521
1522 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1523
1524 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1525 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1526 instruction, the index list may have zero or more indexes, which are required
1527 to make sense for the type of "CSTPTR".</dd>
1528
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1529 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1530
1531 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1532 constants.</dd>
1533
1534 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1535 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1536
1537 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1538 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1539
1540 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1541
1542 <dd>Perform the <a href="#i_extractelement">extractelement
1543 operation</a> on constants.
1544
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1545 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1546
1547 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1548 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1549
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1550
1551 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1552
1553 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1554 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1555
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1556 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1557
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1558 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1559 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1560 binary</a> operations. The constraints on operands are the same as those for
1561 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1562 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1563</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1564</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1565
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1566<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1567<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1568<!-- *********************************************************************** -->
1569
1570<!-- ======================================================================= -->
1571<div class="doc_subsection">
1572<a name="inlineasm">Inline Assembler Expressions</a>
1573</div>
1574
1575<div class="doc_text">
1576
1577<p>
1578LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1579Module-Level Inline Assembly</a>) through the use of a special value. This
1580value represents the inline assembler as a string (containing the instructions
1581to emit), a list of operand constraints (stored as a string), and a flag that
1582indicates whether or not the inline asm expression has side effects. An example
1583inline assembler expression is:
1584</p>
1585
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1586<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1587<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1588i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1589</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1590</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1591
1592<p>
1593Inline assembler expressions may <b>only</b> be used as the callee operand of
1594a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1595</p>
1596
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1597<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1598<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1599%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1600</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1601</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1602
1603<p>
1604Inline asms with side effects not visible in the constraint list must be marked
1605as having side effects. This is done through the use of the
1606'<tt>sideeffect</tt>' keyword, like so:
1607</p>
1608
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1609<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1610<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1611call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1612</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]1613</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1614
1615<p>TODO: The format of the asm and constraints string still need to be
1616documented here. Constraints on what can be done (e.g. duplication, moving, etc
1617need to be documented).
1618</p>
1619
1620</div>
1621
1622<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1623<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1624<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1626<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1627
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1628<p>The LLVM instruction set consists of several different
1629classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1630instructions</a>, <a href="#binaryops">binary instructions</a>,
1631<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1632 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1633instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1634
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1635</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1636
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1637<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsection"> <a name="terminators">Terminator
1639Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1640
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1641<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1642
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1643<p>As mentioned <a href="#functionstructure">previously</a>, every
1644basic block in a program ends with a "Terminator" instruction, which
1645indicates which block should be executed after the current block is
1646finished. These terminator instructions typically yield a '<tt>void</tt>'
1647value: they produce control flow, not values (the one exception being
1648the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1649<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1650 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1651instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1652the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1653 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1654 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1655
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1656</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1658<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1659<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1660Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1661<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1662<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1663<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1664 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1666<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1667<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1668value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1669<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1670returns a value and then causes control flow, and one that just causes
1671control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1672<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1673<p>The '<tt>ret</tt>' instruction may return any '<a
1674 href="#t_firstclass">first class</a>' type. Notice that a function is
1675not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1676instruction inside of the function that returns a value that does not
1677match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1679<p>When the '<tt>ret</tt>' instruction is executed, control flow
1680returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1681 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1682the instruction after the call. If the caller was an "<a
1683 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1684at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1685returns a value, that value shall set the call or invoke instruction's
1686return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1688<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1689 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1690</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1691</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1692<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1693<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1694<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1696<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1697</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1698<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699<p>The '<tt>br</tt>' instruction is used to cause control flow to
1700transfer to a different basic block in the current function. There are
1701two forms of this instruction, corresponding to a conditional branch
1702and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1705single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1706unconditional form of the '<tt>br</tt>' instruction takes a single
1707'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1708<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1709<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1710argument is evaluated. If the value is <tt>true</tt>, control flows
1711to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1712control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1714<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
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1715 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1716</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1717<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1718<div class="doc_subsubsection">
1719 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1720</div>
1721
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1722<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1724
1725<pre>
1726 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1727</pre>
1728
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1730
1731<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1732several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1733instruction, allowing a branch to occur to one of many possible
1734destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1735
1736
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1738
1739<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1740comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1741an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1742table is not allowed to contain duplicate constant entries.</p>
1743
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1745
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1746<p>The <tt>switch</tt> instruction specifies a table of values and
1747destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1748table is searched for the given value. If the value is found, control flow is
1749transfered to the corresponding destination; otherwise, control flow is
1750transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1752<h5>Implementation:</h5>
1753
1754<p>Depending on properties of the target machine and the particular
1755<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1756ways. For example, it could be generated as a series of chained conditional
1757branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1758
1759<h5>Example:</h5>
1760
1761<pre>
1762 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1763 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1764 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1765
1766 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1767 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1768
1769 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1770 switch i32 %val, label %otherwise [ i32 0, label %onzero
1771 i32 1, label %onone
1772 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1774</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1775
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1776<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1777<div class="doc_subsubsection">
1778 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1779</div>
1780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1783<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1784
1785<pre>
1786 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1787 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1788</pre>
1789
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1790<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1791
1792<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1793function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1794'<tt>normal</tt>' label or the
1795'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1796"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1797"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1798href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1799continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1802
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1803<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1806 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1807 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1808 convention</a> the call should use. If none is specified, the call defaults
1809 to using C calling conventions.
1810 </li>
1811 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1812 function value being invoked. In most cases, this is a direct function
1813 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1814 an arbitrary pointer to function value.
1815 </li>
1816
1817 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1818 function to be invoked. </li>
1819
1820 <li>'<tt>function args</tt>': argument list whose types match the function
1821 signature argument types. If the function signature indicates the function
1822 accepts a variable number of arguments, the extra arguments can be
1823 specified. </li>
1824
1825 <li>'<tt>normal label</tt>': the label reached when the called function
1826 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1827
1828 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1829 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1831</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1833<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1834
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1835<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1836href="#i_call">call</a></tt>' instruction in most regards. The primary
1837difference is that it establishes an association with a label, which is used by
1838the runtime library to unwind the stack.</p>
1839
1840<p>This instruction is used in languages with destructors to ensure that proper
1841cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1842exception. Additionally, this is important for implementation of
1843'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1846<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1847 %retval = invoke i32 %Test(i32 15) to label %Continue
1848 unwind label %TestCleanup <i>; {i32}:retval set</i>
1849 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1850 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1851</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1852</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1853
1854
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1855<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1856
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1857<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1858Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1860<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1861
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1862<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1863<pre>
1864 unwind
1865</pre>
1866
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1867<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1868
1869<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1870at the first callee in the dynamic call stack which used an <a
1871href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1872primarily used to implement exception handling.</p>
1873
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1874<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1875
1876<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1877immediately halt. The dynamic call stack is then searched for the first <a
1878href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1879execution continues at the "exceptional" destination block specified by the
1880<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1881dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1882</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1883
1884<!-- _______________________________________________________________________ -->
1885
1886<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1887Instruction</a> </div>
1888
1889<div class="doc_text">
1890
1891<h5>Syntax:</h5>
1892<pre>
1893 unreachable
1894</pre>
1895
1896<h5>Overview:</h5>
1897
1898<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1899instruction is used to inform the optimizer that a particular portion of the
1900code is not reachable. This can be used to indicate that the code after a
1901no-return function cannot be reached, and other facts.</p>
1902
1903<h5>Semantics:</h5>
1904
1905<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1906</div>
1907
1908
1909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1910<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1911<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1912<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1913<p>Binary operators are used to do most of the computation in a
1914program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1915produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1916multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1917The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1918necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1920</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1921<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1922<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1923Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1924<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1925<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1926<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1927</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1928<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1929<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1931<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1932 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1933 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1934Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1935<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1936<p>The value produced is the integer or floating point sum of the two
1937operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1938<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1939<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1940</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1941</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1942<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1943<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1944Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1946<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1947<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1948</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1950<p>The '<tt>sub</tt>' instruction returns the difference of its two
1951operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1952<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1953instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1954<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1955<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1956 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1957values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1958This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1959Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1960<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1961<p>The value produced is the integer or floating point difference of
1962the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1963<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1964<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1965 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1966</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1967</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1968<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1969<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1970Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1971<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1972<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1973<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1974</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1976<p>The '<tt>mul</tt>' instruction returns the product of its two
1977operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1979<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1980 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1981values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1982This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1983Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1984<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1985<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1986two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1987<p>Because the operands are the same width, the result of an integer
1988multiplication is the same whether the operands should be deemed unsigned or
1989signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1991<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1992</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1995<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1996</a></div>
1997<div class="doc_text">
1998<h5>Syntax:</h5>
1999<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2000</pre>
2001<h5>Overview:</h5>
2002<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2003operands.</p>
2004<h5>Arguments:</h5>
2005<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2006<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2007types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2008of the values in which case the elements must be integers.</p>
2009<h5>Semantics:</h5>
2010<p>The value produced is the unsigned integer quotient of the two operands. This
2011instruction always performs an unsigned division operation, regardless of
2012whether the arguments are unsigned or not.</p>
2013<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2014<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2015</pre>
2016</div>
2017<!-- _______________________________________________________________________ -->
2018<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2019</a> </div>
2020<div class="doc_text">
2021<h5>Syntax:</h5>
2022<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2023</pre>
2024<h5>Overview:</h5>
2025<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2026operands.</p>
2027<h5>Arguments:</h5>
2028<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2029<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2030types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2031of the values in which case the elements must be integers.</p>
2032<h5>Semantics:</h5>
2033<p>The value produced is the signed integer quotient of the two operands. This
2034instruction always performs a signed division operation, regardless of whether
2035the arguments are signed or not.</p>
2036<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2037<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2038</pre>
2039</div>
2040<!-- _______________________________________________________________________ -->
2041<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2042Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2043<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2045<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2046</pre>
2047<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2048<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2049operands.</p>
2050<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2051<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2052<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2053identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2054versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2055<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2056<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2057<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2058<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2059</pre>
2060</div>
2061<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2062<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2063</div>
2064<div class="doc_text">
2065<h5>Syntax:</h5>
2066<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2067</pre>
2068<h5>Overview:</h5>
2069<p>The '<tt>urem</tt>' instruction returns the remainder from the
2070unsigned division of its two arguments.</p>
2071<h5>Arguments:</h5>
2072<p>The two arguments to the '<tt>urem</tt>' instruction must be
2073<a href="#t_integer">integer</a> values. Both arguments must have identical
2074types.</p>
2075<h5>Semantics:</h5>
2076<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2077This instruction always performs an unsigned division to get the remainder,
2078regardless of whether the arguments are unsigned or not.</p>
2079<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2080<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2081</pre>
2082
2083</div>
2084<!-- _______________________________________________________________________ -->
2085<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2086Instruction</a> </div>
2087<div class="doc_text">
2088<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2089<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2090</pre>
2091<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2092<p>The '<tt>srem</tt>' instruction returns the remainder from the
2093signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2094<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2095<p>The two arguments to the '<tt>srem</tt>' instruction must be
2096<a href="#t_integer">integer</a> values. Both arguments must have identical
2097types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2098<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2099<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2100has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2101operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2102a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2103 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2104Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2105please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2106Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2107<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2108<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2109</pre>
2110
2111</div>
2112<!-- _______________________________________________________________________ -->
2113<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2114Instruction</a> </div>
2115<div class="doc_text">
2116<h5>Syntax:</h5>
2117<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2118</pre>
2119<h5>Overview:</h5>
2120<p>The '<tt>frem</tt>' instruction returns the remainder from the
2121division of its two operands.</p>
2122<h5>Arguments:</h5>
2123<p>The two arguments to the '<tt>frem</tt>' instruction must be
2124<a href="#t_floating">floating point</a> values. Both arguments must have
2125identical types.</p>
2126<h5>Semantics:</h5>
2127<p>This instruction returns the <i>remainder</i> of a division.</p>
2128<h5>Example:</h5>
2129<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2130</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2131</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2132
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2133<!-- ======================================================================= -->
2134<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2135Operations</a> </div>
2136<div class="doc_text">
2137<p>Bitwise binary operators are used to do various forms of
2138bit-twiddling in a program. They are generally very efficient
2139instructions and can commonly be strength reduced from other
2140instructions. They require two operands, execute an operation on them,
2141and produce a single value. The resulting value of the bitwise binary
2142operators is always the same type as its first operand.</p>
2143</div>
2144
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2145<!-- _______________________________________________________________________ -->
2146<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2147Instruction</a> </div>
2148<div class="doc_text">
2149<h5>Syntax:</h5>
2150<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2151</pre>
2152<h5>Overview:</h5>
2153<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2154the left a specified number of bits.</p>
2155<h5>Arguments:</h5>
2156<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2157 href="#t_integer">integer</a> type.</p>
2158<h5>Semantics:</h5>
2159<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2160<h5>Example:</h5><pre>
2161 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2162 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2163 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2164</pre>
2165</div>
2166<!-- _______________________________________________________________________ -->
2167<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2168Instruction</a> </div>
2169<div class="doc_text">
2170<h5>Syntax:</h5>
2171<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2172</pre>
2173
2174<h5>Overview:</h5>
2175<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2176operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2177
2178<h5>Arguments:</h5>
2179<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2180<a href="#t_integer">integer</a> type.</p>
2181
2182<h5>Semantics:</h5>
2183<p>This instruction always performs a logical shift right operation. The most
2184significant bits of the result will be filled with zero bits after the
2185shift.</p>
2186
2187<h5>Example:</h5>
2188<pre>
2189 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2190 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2191 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2192 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2193</pre>
2194</div>
2195
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2196<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2197<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2198Instruction</a> </div>
2199<div class="doc_text">
2200
2201<h5>Syntax:</h5>
2202<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2203</pre>
2204
2205<h5>Overview:</h5>
2206<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2207operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2208
2209<h5>Arguments:</h5>
2210<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2211<a href="#t_integer">integer</a> type.</p>
2212
2213<h5>Semantics:</h5>
2214<p>This instruction always performs an arithmetic shift right operation,
2215The most significant bits of the result will be filled with the sign bit
2216of <tt>var1</tt>.</p>
2217
2218<h5>Example:</h5>
2219<pre>
2220 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2221 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2222 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2223 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2224</pre>
2225</div>
2226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2227<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2228<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2229Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2230<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2231<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2232<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2233</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2234<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2235<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2236its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2237<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2238<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2239 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2240identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2241<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2242<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2243<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2244<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2245<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2246 <tbody>
2247 <tr>
2248 <td>In0</td>
2249 <td>In1</td>
2250 <td>Out</td>
2251 </tr>
2252 <tr>
2253 <td>0</td>
2254 <td>0</td>
2255 <td>0</td>
2256 </tr>
2257 <tr>
2258 <td>0</td>
2259 <td>1</td>
2260 <td>0</td>
2261 </tr>
2262 <tr>
2263 <td>1</td>
2264 <td>0</td>
2265 <td>0</td>
2266 </tr>
2267 <tr>
2268 <td>1</td>
2269 <td>1</td>
2270 <td>1</td>
2271 </tr>
2272 </tbody>
2273</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2274</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2275<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2276<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2277 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2278 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2279</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2280</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2281<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2282<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2283<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2284<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2285<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2286</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2287<h5>Overview:</h5>
2288<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2289or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2290<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2291<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2292 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2293identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2294<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2295<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2296<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2297<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2298<table border="1" cellspacing="0" cellpadding="4">
2299 <tbody>
2300 <tr>
2301 <td>In0</td>
2302 <td>In1</td>
2303 <td>Out</td>
2304 </tr>
2305 <tr>
2306 <td>0</td>
2307 <td>0</td>
2308 <td>0</td>
2309 </tr>
2310 <tr>
2311 <td>0</td>
2312 <td>1</td>
2313 <td>1</td>
2314 </tr>
2315 <tr>
2316 <td>1</td>
2317 <td>0</td>
2318 <td>1</td>
2319 </tr>
2320 <tr>
2321 <td>1</td>
2322 <td>1</td>
2323 <td>1</td>
2324 </tr>
2325 </tbody>
2326</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2327</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2328<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2329<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2330 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2331 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2332</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2333</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2334<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2335<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2336Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2337<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2338<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2339<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2340</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2341<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2342<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2343or of its two operands. The <tt>xor</tt> is used to implement the
2344"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2345<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2346<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2347 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2348identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2349<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2350<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2351<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2352<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2353<table border="1" cellspacing="0" cellpadding="4">
2354 <tbody>
2355 <tr>
2356 <td>In0</td>
2357 <td>In1</td>
2358 <td>Out</td>
2359 </tr>
2360 <tr>
2361 <td>0</td>
2362 <td>0</td>
2363 <td>0</td>
2364 </tr>
2365 <tr>
2366 <td>0</td>
2367 <td>1</td>
2368 <td>1</td>
2369 </tr>
2370 <tr>
2371 <td>1</td>
2372 <td>0</td>
2373 <td>1</td>
2374 </tr>
2375 <tr>
2376 <td>1</td>
2377 <td>1</td>
2378 <td>0</td>
2379 </tr>
2380 </tbody>
2381</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2382</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2383<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2384<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2385<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2386 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2387 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2388 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2389</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2390</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2392<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2393<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2394 <a name="vectorops">Vector Operations</a>
2395</div>
2396
2397<div class="doc_text">
2398
2399<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2400target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2401vector-specific operations needed to process vectors effectively. While LLVM
2402does directly support these vector operations, many sophisticated algorithms
2403will want to use target-specific intrinsics to take full advantage of a specific
2404target.</p>
2405
2406</div>
2407
2408<!-- _______________________________________________________________________ -->
2409<div class="doc_subsubsection">
2410 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2411</div>
2412
2413<div class="doc_text">
2414
2415<h5>Syntax:</h5>
2416
2417<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2418 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2419</pre>
2420
2421<h5>Overview:</h5>
2422
2423<p>
2424The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2425element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2426</p>
2427
2428
2429<h5>Arguments:</h5>
2430
2431<p>
2432The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2433value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2434an index indicating the position from which to extract the element.
2435The index may be a variable.</p>
2436
2437<h5>Semantics:</h5>
2438
2439<p>
2440The result is a scalar of the same type as the element type of
2441<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2442<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2443results are undefined.
2444</p>
2445
2446<h5>Example:</h5>
2447
2448<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2449 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2450</pre>
2451</div>
2452
2453
2454<!-- _______________________________________________________________________ -->
2455<div class="doc_subsubsection">
2456 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2457</div>
2458
2459<div class="doc_text">
2460
2461<h5>Syntax:</h5>
2462
2463<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2464 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2465</pre>
2466
2467<h5>Overview:</h5>
2468
2469<p>
2470The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2471element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2472</p>
2473
2474
2475<h5>Arguments:</h5>
2476
2477<p>
2478The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2479value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2480scalar value whose type must equal the element type of the first
2481operand. The third operand is an index indicating the position at
2482which to insert the value. The index may be a variable.</p>
2483
2484<h5>Semantics:</h5>
2485
2486<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2487The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2488element values are those of <tt>val</tt> except at position
2489<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2490exceeds the length of <tt>val</tt>, the results are undefined.
2491</p>
2492
2493<h5>Example:</h5>
2494
2495<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2496 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2497</pre>
2498</div>
2499
2500<!-- _______________________________________________________________________ -->
2501<div class="doc_subsubsection">
2502 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2503</div>
2504
2505<div class="doc_text">
2506
2507<h5>Syntax:</h5>
2508
2509<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2510 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2511</pre>
2512
2513<h5>Overview:</h5>
2514
2515<p>
2516The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2517from two input vectors, returning a vector of the same type.
2518</p>
2519
2520<h5>Arguments:</h5>
2521
2522<p>
2523The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2524with types that match each other and types that match the result of the
2525instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2526of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2527</p>
2528
2529<p>
2530The shuffle mask operand is required to be a constant vector with either
2531constant integer or undef values.
2532</p>
2533
2534<h5>Semantics:</h5>
2535
2536<p>
2537The elements of the two input vectors are numbered from left to right across
2538both of the vectors. The shuffle mask operand specifies, for each element of
2539the result vector, which element of the two input registers the result element
2540gets. The element selector may be undef (meaning "don't care") and the second
2541operand may be undef if performing a shuffle from only one vector.
2542</p>
2543
2544<h5>Example:</h5>
2545
2546<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2547 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2548 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2549 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2550 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2551</pre>
2552</div>
2553
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2554
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2555<!-- ======================================================================= -->
2556<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2557 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2558</div>
2559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2560<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2561
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2562<p>A key design point of an SSA-based representation is how it
2563represents memory. In LLVM, no memory locations are in SSA form, which
2564makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2565allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2567</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2568
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2569<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2570<div class="doc_subsubsection">
2571 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2572</div>
2573
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2574<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2575
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2576<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2577
2578<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2579 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2580</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2582<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2583
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2584<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2585heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2588
2589<p>The '<tt>malloc</tt>' instruction allocates
2590<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2591bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2592appropriate type to the program. If "NumElements" is specified, it is the
2593number of elements allocated. If an alignment is specified, the value result
2594of the allocation is guaranteed to be aligned to at least that boundary. If
2595not specified, or if zero, the target can choose to align the allocation on any
2596convenient boundary.</p>
2597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2598<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2599
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2600<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2601
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2602<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2603a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2604
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2605<h5>Example:</h5>
2606
2607<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2608 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2609
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2610 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2611 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2612 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2613 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2614 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2616</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2617
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2618<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2619<div class="doc_subsubsection">
2620 <a name="i_free">'<tt>free</tt>' Instruction</a>
2621</div>
2622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2623<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2625<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2626
2627<pre>
2628 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2629</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2630
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2631<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2632
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2633<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2634memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2636<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2637
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2638<p>'<tt>value</tt>' shall be a pointer value that points to a value
2639that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2640instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2642<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2643
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2644<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2645after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2646
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2647<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2648
2649<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2650 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2651 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2652</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2653</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2654
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2655<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2656<div class="doc_subsubsection">
2657 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2658</div>
2659
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2660<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2661
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2662<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2663
2664<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2665 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2666</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2667
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2668<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2669
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2670<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2671currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2672returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2673
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2674<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2675
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2676<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2677bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2678appropriate type to the program. If "NumElements" is specified, it is the
2679number of elements allocated. If an alignment is specified, the value result
2680of the allocation is guaranteed to be aligned to at least that boundary. If
2681not specified, or if zero, the target can choose to align the allocation on any
2682convenient boundary.</p>
2683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2684<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2686<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2687
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2688<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2689memory is automatically released when the function returns. The '<tt>alloca</tt>'
2690instruction is commonly used to represent automatic variables that must
2691have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2692 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2693instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2695<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2696
2697<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2698 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2699 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2700 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2701 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2702</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2703</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2704
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2705<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2706<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2707Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2708<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2709<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2710<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2711<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2712<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2713<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2714<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2715address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2716 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2717marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2718the number or order of execution of this <tt>load</tt> with other
2719volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2720instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2721<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2722<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2723<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2724<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2725 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2726 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2727 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2728</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2729</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2730<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2731<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2732Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2733<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2734<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2735<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2736 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2737</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2738<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2739<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2740<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2741<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2742to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2743operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2744operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2745optimizer is not allowed to modify the number or order of execution of
2746this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2747 href="#i_store">store</a></tt> instructions.</p>
2748<h5>Semantics:</h5>
2749<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2750at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2751<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2752<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2753 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2754 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2755 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2756</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2757</div>
2758
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2759<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2760<div class="doc_subsubsection">
2761 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2762</div>
2763
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2764<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2765<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2766<pre>
2767 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2768</pre>
2769
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2770<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2771
2772<p>
2773The '<tt>getelementptr</tt>' instruction is used to get the address of a
2774subelement of an aggregate data structure.</p>
2775
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2776<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2777
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2778<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2779elements of the aggregate object to index to. The actual types of the arguments
2780provided depend on the type of the first pointer argument. The
2781'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2782levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2783structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2784into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2785be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2786
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2787<p>For example, let's consider a C code fragment and how it gets
2788compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2789
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2790<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2791<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2792struct RT {
2793 char A;
2794 i32 B[10][20];
2795 char C;
2796};
2797struct ST {
2798 i32 X;
2799 double Y;
2800 struct RT Z;
2801};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2802
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2803i32 *foo(struct ST *s) {
2804 return &amp;s[1].Z.B[5][13];
2805}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2806</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2807</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2808
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2809<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2810
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2811<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2812<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2813%RT = type { i8 , [10 x [20 x i32]], i8 }
2814%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2815
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2816define i32* %foo(%ST* %s) {
2817entry:
2818 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2819 ret i32* %reg
2820}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2821</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]2822</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2823
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2824<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2825
2826<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2827on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2828and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2829<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2830to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2831<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2832
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2833<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2834type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2835}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2836the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2837i8 }</tt>' type, another structure. The third index indexes into the second
2838element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2839array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2840'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2841to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2842
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2843<p>Note that it is perfectly legal to index partially through a
2844structure, returning a pointer to an inner element. Because of this,
2845the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2846
2847<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2848 define i32* %foo(%ST* %s) {
2849 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2850 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2851 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2852 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2853 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2854 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2855 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2856</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2857
2858<p>Note that it is undefined to access an array out of bounds: array and
2859pointer indexes must always be within the defined bounds of the array type.
2860The one exception for this rules is zero length arrays. These arrays are
2861defined to be accessible as variable length arrays, which requires access
2862beyond the zero'th element.</p>
2863
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2864<p>The getelementptr instruction is often confusing. For some more insight
2865into how it works, see <a href="GetElementPtr.html">the getelementptr
2866FAQ</a>.</p>
2867
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2868<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2869
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2870<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2871 <i>; yields [12 x i8]*:aptr</i>
2872 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2873</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2874</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2877<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2878</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2879<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2880<p>The instructions in this category are the conversion instructions (casting)
2881which all take a single operand and a type. They perform various bit conversions
2882on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2883</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2884
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2885<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2886<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2887 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2888</div>
2889<div class="doc_text">
2890
2891<h5>Syntax:</h5>
2892<pre>
2893 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2894</pre>
2895
2896<h5>Overview:</h5>
2897<p>
2898The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2899</p>
2900
2901<h5>Arguments:</h5>
2902<p>
2903The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2904be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2905and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2906type. The bit size of <tt>value</tt> must be larger than the bit size of
2907<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2908
2909<h5>Semantics:</h5>
2910<p>
2911The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2912and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2913larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2914It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2915
2916<h5>Example:</h5>
2917<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2918 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2919 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2920 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2921</pre>
2922</div>
2923
2924<!-- _______________________________________________________________________ -->
2925<div class="doc_subsubsection">
2926 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2927</div>
2928<div class="doc_text">
2929
2930<h5>Syntax:</h5>
2931<pre>
2932 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2933</pre>
2934
2935<h5>Overview:</h5>
2936<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2937<tt>ty2</tt>.</p>
2938
2939
2940<h5>Arguments:</h5>
2941<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2942<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2943also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2944<tt>value</tt> must be smaller than the bit size of the destination type,
2945<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2946
2947<h5>Semantics:</h5>
2948<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]2949bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2950
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2951<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2952
2953<h5>Example:</h5>
2954<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2955 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2956 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2957</pre>
2958</div>
2959
2960<!-- _______________________________________________________________________ -->
2961<div class="doc_subsubsection">
2962 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2963</div>
2964<div class="doc_text">
2965
2966<h5>Syntax:</h5>
2967<pre>
2968 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2969</pre>
2970
2971<h5>Overview:</h5>
2972<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2973
2974<h5>Arguments:</h5>
2975<p>
2976The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2977<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2978also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2979<tt>value</tt> must be smaller than the bit size of the destination type,
2980<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2981
2982<h5>Semantics:</h5>
2983<p>
2984The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2985bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]2986the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2987
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2988<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2989
2990<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2991<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2992 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2993 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2994</pre>
2995</div>
2996
2997<!-- _______________________________________________________________________ -->
2998<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2999 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3000</div>
3001
3002<div class="doc_text">
3003
3004<h5>Syntax:</h5>
3005
3006<pre>
3007 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3008</pre>
3009
3010<h5>Overview:</h5>
3011<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3012<tt>ty2</tt>.</p>
3013
3014
3015<h5>Arguments:</h5>
3016<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3017 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3018cast it to. The size of <tt>value</tt> must be larger than the size of
3019<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3020<i>no-op cast</i>.</p>
3021
3022<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3023<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3024<a href="#t_floating">floating point</a> type to a smaller
3025<a href="#t_floating">floating point</a> type. If the value cannot fit within
3026the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3027
3028<h5>Example:</h5>
3029<pre>
3030 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3031 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3032</pre>
3033</div>
3034
3035<!-- _______________________________________________________________________ -->
3036<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3037 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3038</div>
3039<div class="doc_text">
3040
3041<h5>Syntax:</h5>
3042<pre>
3043 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3044</pre>
3045
3046<h5>Overview:</h5>
3047<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3048floating point value.</p>
3049
3050<h5>Arguments:</h5>
3051<p>The '<tt>fpext</tt>' instruction takes a
3052<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3053and a <a href="#t_floating">floating point</a> type to cast it to. The source
3054type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3055
3056<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3057<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3058<a href="#t_floating">floating point</a> type to a larger
3059<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3060used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3061<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3062
3063<h5>Example:</h5>
3064<pre>
3065 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3066 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3067</pre>
3068</div>
3069
3070<!-- _______________________________________________________________________ -->
3071<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3072 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3073</div>
3074<div class="doc_text">
3075
3076<h5>Syntax:</h5>
3077<pre>
3078 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3079</pre>
3080
3081<h5>Overview:</h5>
3082<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3083unsigned integer equivalent of type <tt>ty2</tt>.
3084</p>
3085
3086<h5>Arguments:</h5>
3087<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3088<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3089must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3090
3091<h5>Semantics:</h5>
3092<p> The '<tt>fp2uint</tt>' instruction converts its
3093<a href="#t_floating">floating point</a> operand into the nearest (rounding
3094towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3095the results are undefined.</p>
3096
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3097<p>When converting to i1, the conversion is done as a comparison against
3098zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3099If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3100
3101<h5>Example:</h5>
3102<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3103 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3104 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3105 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3106</pre>
3107</div>
3108
3109<!-- _______________________________________________________________________ -->
3110<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3111 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3112</div>
3113<div class="doc_text">
3114
3115<h5>Syntax:</h5>
3116<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3117 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3118</pre>
3119
3120<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3121<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3122<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3123</p>
3124
3125
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3126<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3127<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3128<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3129must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3130
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3131<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3132<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3133<a href="#t_floating">floating point</a> operand into the nearest (rounding
3134towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3135the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3136
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3137<p>When converting to i1, the conversion is done as a comparison against
3138zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3139If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3140
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3141<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3142<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3143 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3144 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3145 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3146</pre>
3147</div>
3148
3149<!-- _______________________________________________________________________ -->
3150<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3151 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3152</div>
3153<div class="doc_text">
3154
3155<h5>Syntax:</h5>
3156<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3157 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3158</pre>
3159
3160<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3161<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3162integer and converts that value to the <tt>ty2</tt> type.</p>
3163
3164
3165<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3166<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3167<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3168be a <a href="#t_floating">floating point</a> type.</p>
3169
3170<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3171<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3172integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3173the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3174
3175
3176<h5>Example:</h5>
3177<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3178 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3179 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3180</pre>
3181</div>
3182
3183<!-- _______________________________________________________________________ -->
3184<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3185 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3186</div>
3187<div class="doc_text">
3188
3189<h5>Syntax:</h5>
3190<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3191 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3192</pre>
3193
3194<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3195<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3196integer and converts that value to the <tt>ty2</tt> type.</p>
3197
3198<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3199<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3200<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3201a <a href="#t_floating">floating point</a> type.</p>
3202
3203<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3204<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3205integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3206the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3207
3208<h5>Example:</h5>
3209<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3210 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3211 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3212</pre>
3213</div>
3214
3215<!-- _______________________________________________________________________ -->
3216<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3217 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3218</div>
3219<div class="doc_text">
3220
3221<h5>Syntax:</h5>
3222<pre>
3223 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3224</pre>
3225
3226<h5>Overview:</h5>
3227<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3228the integer type <tt>ty2</tt>.</p>
3229
3230<h5>Arguments:</h5>
3231<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3232must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3233<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3234
3235<h5>Semantics:</h5>
3236<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3237<tt>ty2</tt> by interpreting the pointer value as an integer and either
3238truncating or zero extending that value to the size of the integer type. If
3239<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3240<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3241are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3242change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3243
3244<h5>Example:</h5>
3245<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3246 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3247 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3248</pre>
3249</div>
3250
3251<!-- _______________________________________________________________________ -->
3252<div class="doc_subsubsection">
3253 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3254</div>
3255<div class="doc_text">
3256
3257<h5>Syntax:</h5>
3258<pre>
3259 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3260</pre>
3261
3262<h5>Overview:</h5>
3263<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3264a pointer type, <tt>ty2</tt>.</p>
3265
3266<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3267<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3268value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3269<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3270
3271<h5>Semantics:</h5>
3272<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3273<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3274the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3275size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3276the size of a pointer then a zero extension is done. If they are the same size,
3277nothing is done (<i>no-op cast</i>).</p>
3278
3279<h5>Example:</h5>
3280<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3281 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3282 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3283 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3284</pre>
3285</div>
3286
3287<!-- _______________________________________________________________________ -->
3288<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3289 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3290</div>
3291<div class="doc_text">
3292
3293<h5>Syntax:</h5>
3294<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3295 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3296</pre>
3297
3298<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3299<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3300<tt>ty2</tt> without changing any bits.</p>
3301
3302<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3303<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3304a first class value, and a type to cast it to, which must also be a <a
3305 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3306and the destination type, <tt>ty2</tt>, must be identical. If the source
3307type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3308
3309<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3310<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3311<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3312this conversion. The conversion is done as if the <tt>value</tt> had been
3313stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3314converted to other pointer types with this instruction. To convert pointers to
3315other types, use the <a href="#i_inttoptr">inttoptr</a> or
3316<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3317
3318<h5>Example:</h5>
3319<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3320 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3321 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3322 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3323</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3324</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3325
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3326<!-- ======================================================================= -->
3327<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3328<div class="doc_text">
3329<p>The instructions in this category are the "miscellaneous"
3330instructions, which defy better classification.</p>
3331</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3332
3333<!-- _______________________________________________________________________ -->
3334<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3335</div>
3336<div class="doc_text">
3337<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3338<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3339</pre>
3340<h5>Overview:</h5>
3341<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3342of its two integer operands.</p>
3343<h5>Arguments:</h5>
3344<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3345the condition code indicating the kind of comparison to perform. It is not
3346a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3347<ol>
3348 <li><tt>eq</tt>: equal</li>
3349 <li><tt>ne</tt>: not equal </li>
3350 <li><tt>ugt</tt>: unsigned greater than</li>
3351 <li><tt>uge</tt>: unsigned greater or equal</li>
3352 <li><tt>ult</tt>: unsigned less than</li>
3353 <li><tt>ule</tt>: unsigned less or equal</li>
3354 <li><tt>sgt</tt>: signed greater than</li>
3355 <li><tt>sge</tt>: signed greater or equal</li>
3356 <li><tt>slt</tt>: signed less than</li>
3357 <li><tt>sle</tt>: signed less or equal</li>
3358</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3359<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3360<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3361<h5>Semantics:</h5>
3362<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3363the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3364yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3365<ol>
3366 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3367 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3368 </li>
3369 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3370 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3371 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3372 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3373 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3374 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3375 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3376 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3377 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3378 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3379 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3380 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3381 <li><tt>sge</tt>: interprets the operands as signed values and yields
3382 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3383 <li><tt>slt</tt>: interprets the operands as signed values and yields
3384 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3385 <li><tt>sle</tt>: interprets the operands as signed values and yields
3386 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3387</ol>
3388<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3389values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3390
3391<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3392<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3393 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3394 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3395 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3396 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3397 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3398</pre>
3399</div>
3400
3401<!-- _______________________________________________________________________ -->
3402<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3403</div>
3404<div class="doc_text">
3405<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3406<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3407</pre>
3408<h5>Overview:</h5>
3409<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3410of its floating point operands.</p>
3411<h5>Arguments:</h5>
3412<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3413the condition code indicating the kind of comparison to perform. It is not
3414a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3415<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3416 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3417 <li><tt>oeq</tt>: ordered and equal</li>
3418 <li><tt>ogt</tt>: ordered and greater than </li>
3419 <li><tt>oge</tt>: ordered and greater than or equal</li>
3420 <li><tt>olt</tt>: ordered and less than </li>
3421 <li><tt>ole</tt>: ordered and less than or equal</li>
3422 <li><tt>one</tt>: ordered and not equal</li>
3423 <li><tt>ord</tt>: ordered (no nans)</li>
3424 <li><tt>ueq</tt>: unordered or equal</li>
3425 <li><tt>ugt</tt>: unordered or greater than </li>
3426 <li><tt>uge</tt>: unordered or greater than or equal</li>
3427 <li><tt>ult</tt>: unordered or less than </li>
3428 <li><tt>ule</tt>: unordered or less than or equal</li>
3429 <li><tt>une</tt>: unordered or not equal</li>
3430 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3431 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3432</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3433<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3434<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3435<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3436<a href="#t_floating">floating point</a> typed. They must have identical
3437types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3438<h5>Semantics:</h5>
3439<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3440the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3441yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3442<ol>
3443 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3444 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3445 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3446 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3447 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3448 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3449 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3450 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3451 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3452 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3453 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3454 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3455 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3456 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3457 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3458 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3459 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3460 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3461 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3462 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3463 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3464 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3465 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3466 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3467 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3468 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3469 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3470 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3471</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3472
3473<h5>Example:</h5>
3474<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3475 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3476 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3477 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3478</pre>
3479</div>
3480
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3481<!-- _______________________________________________________________________ -->
3482<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3483Instruction</a> </div>
3484<div class="doc_text">
3485<h5>Syntax:</h5>
3486<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3487<h5>Overview:</h5>
3488<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3489the SSA graph representing the function.</p>
3490<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3491<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3492field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3493as arguments, with one pair for each predecessor basic block of the
3494current block. Only values of <a href="#t_firstclass">first class</a>
3495type may be used as the value arguments to the PHI node. Only labels
3496may be used as the label arguments.</p>
3497<p>There must be no non-phi instructions between the start of a basic
3498block and the PHI instructions: i.e. PHI instructions must be first in
3499a basic block.</p>
3500<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3501<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3502specified by the pair corresponding to the predecessor basic block that executed
3503just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3504<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3505<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3506</div>
3507
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3508<!-- _______________________________________________________________________ -->
3509<div class="doc_subsubsection">
3510 <a name="i_select">'<tt>select</tt>' Instruction</a>
3511</div>
3512
3513<div class="doc_text">
3514
3515<h5>Syntax:</h5>
3516
3517<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3518 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3519</pre>
3520
3521<h5>Overview:</h5>
3522
3523<p>
3524The '<tt>select</tt>' instruction is used to choose one value based on a
3525condition, without branching.
3526</p>
3527
3528
3529<h5>Arguments:</h5>
3530
3531<p>
3532The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
3533</p>
3534
3535<h5>Semantics:</h5>
3536
3537<p>
3538If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3539value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3540</p>
3541
3542<h5>Example:</h5>
3543
3544<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3545 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3546</pre>
3547</div>
3548
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3549
3550<!-- _______________________________________________________________________ -->
3551<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3552 <a name="i_call">'<tt>call</tt>' Instruction</a>
3553</div>
3554
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3555<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3556
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3557<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3558<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3559 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3560</pre>
3561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3562<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3563
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3564<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3565
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3566<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3567
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3568<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3569
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3570<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3571 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3572 <p>The optional "tail" marker indicates whether the callee function accesses
3573 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3574 function call is eligible for tail call optimization. Note that calls may
3575 be marked "tail" even if they do not occur before a <a
3576 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3577 </li>
3578 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3579 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3580 convention</a> the call should use. If none is specified, the call defaults
3581 to using C calling conventions.
3582 </li>
3583 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3584 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3585 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3586 signature. This type can be omitted if the function is not varargs and
3587 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3588 </li>
3589 <li>
3590 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3591 be invoked. In most cases, this is a direct function invocation, but
3592 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3593 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3594 </li>
3595 <li>
3596 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3597 function signature argument types. All arguments must be of
3598 <a href="#t_firstclass">first class</a> type. If the function signature
3599 indicates the function accepts a variable number of arguments, the extra
3600 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3601 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3602</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3604<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3605
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3606<p>The '<tt>call</tt>' instruction is used to cause control flow to
3607transfer to a specified function, with its incoming arguments bound to
3608the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3609instruction in the called function, control flow continues with the
3610instruction after the function call, and the return value of the
3611function is bound to the result argument. This is a simpler case of
3612the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3614<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3615
3616<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3617 %retval = call i32 %test(i32 %argc)
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3618 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3619 %X = tail call i32 %foo()
3620 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3621</pre>
3622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3623</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3624
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3625<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3626<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3627 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3628</div>
3629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3630<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3631
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3632<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3633
3634<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3635 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3636</pre>
3637
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3638<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3639
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3640<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3641the "variable argument" area of a function call. It is used to implement the
3642<tt>va_arg</tt> macro in C.</p>
3643
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3644<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3645
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3646<p>This instruction takes a <tt>va_list*</tt> value and the type of
3647the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3648increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3649actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3650
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3651<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3652
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3653<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3654type from the specified <tt>va_list</tt> and causes the
3655<tt>va_list</tt> to point to the next argument. For more information,
3656see the variable argument handling <a href="#int_varargs">Intrinsic
3657Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3658
3659<p>It is legal for this instruction to be called in a function which does not
3660take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3661function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3662
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3663<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3664href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3665argument.</p>
3666
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3667<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3668
3669<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3670
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3671</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3672
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3673<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3674<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3675<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3676
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3677<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3678
3679<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3680well known names and semantics and are required to follow certain restrictions.
3681Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3682language that does not require changing all of the transformations in LLVM when
3683adding to the language (or the bytecode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3684
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3685<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3686prefix is reserved in LLVM for intrinsic names; thus, function names may not
3687begin with this prefix. Intrinsic functions must always be external functions:
3688you cannot define the body of intrinsic functions. Intrinsic functions may
3689only be used in call or invoke instructions: it is illegal to take the address
3690of an intrinsic function. Additionally, because intrinsic functions are part
3691of the LLVM language, it is required if any are added that they be documented
3692here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3693
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3694<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3695a family of functions that perform the same operation but on different data
3696types. This is most frequent with the integer types. Since LLVM can represent
3697over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3698that can be overloaded based on its arguments. Such an intrinsic will have the
3699names of its argument types encoded into its function name, each
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3700preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3701integer of any width. This leads to a family of functions such as
3702<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3703</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3704
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3705
3706<p>To learn how to add an intrinsic function, please see the
3707<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3708</p>
3709
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3710</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3711
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3712<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3713<div class="doc_subsection">
3714 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3715</div>
3716
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3717<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3718
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3719<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3720 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3721intrinsic functions. These functions are related to the similarly
3722named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3723
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3724<p>All of these functions operate on arguments that use a
3725target-specific value type "<tt>va_list</tt>". The LLVM assembly
3726language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3727transformations should be prepared to handle these functions regardless of
3728the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3729
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3730<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3731instruction and the variable argument handling intrinsic functions are
3732used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3733
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]3734<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3735<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3736define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3737 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3738 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3739 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3740 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3741
3742 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3743 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3744
3745 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3746 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3747 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3748 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3749 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3750
3751 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3752 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3753 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3754}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3755
3756declare void @llvm.va_start(i8*)
3757declare void @llvm.va_copy(i8*, i8*)
3758declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3759</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3760</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3761
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame^]3762</div>
3763
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3764<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3765<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3766 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3767</div>
3768
3769
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3770<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3771<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3772<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3773<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3774<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3775<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3776href="#i_va_arg">va_arg</a></tt>.</p>
3777
3778<h5>Arguments:</h5>
3779
3780<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3781
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3782<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3783
3784<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3785macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3786<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3787<tt>va_arg</tt> will produce the first variable argument passed to the function.
3788Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3789last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3790
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3791</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3792
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3793<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3794<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3795 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3796</div>
3797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3798<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3799<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3800<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3801<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3802
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3803<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3804which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3805or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3806
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3807<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3808
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3809<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3810
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3811<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3812
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3813<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3814macro available in C. In a target-dependent way, it destroys the
3815<tt>va_list</tt> element to which the argument points. Calls to <a
3816href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3817<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3818<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3820</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3821
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3822<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3823<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3824 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3825</div>
3826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3827<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3828
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3829<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3830
3831<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3832 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3833</pre>
3834
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3835<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3836
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3837<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3838from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3839
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3840<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3841
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3842<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3843The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3844
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3845
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3846<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3847
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3848<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3849macro available in C. In a target-dependent way, it copies the source
3850<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3851intrinsic is necessary because the <tt><a href="#int_va_start">
3852llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3853example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3854
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3855</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3856
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3857<!-- ======================================================================= -->
3858<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3859 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3860</div>
3861
3862<div class="doc_text">
3863
3864<p>
3865LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3866Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3867These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3868stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3869href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3870Front-ends for type-safe garbage collected languages should generate these
3871intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3872href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3873</p>
3874</div>
3875
3876<!-- _______________________________________________________________________ -->
3877<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3878 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3879</div>
3880
3881<div class="doc_text">
3882
3883<h5>Syntax:</h5>
3884
3885<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3886 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3887</pre>
3888
3889<h5>Overview:</h5>
3890
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3891<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3892the code generator, and allows some metadata to be associated with it.</p>
3893
3894<h5>Arguments:</h5>
3895
3896<p>The first argument specifies the address of a stack object that contains the
3897root pointer. The second pointer (which must be either a constant or a global
3898value address) contains the meta-data to be associated with the root.</p>
3899
3900<h5>Semantics:</h5>
3901
3902<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3903location. At compile-time, the code generator generates information to allow
3904the runtime to find the pointer at GC safe points.
3905</p>
3906
3907</div>
3908
3909
3910<!-- _______________________________________________________________________ -->
3911<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3912 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3913</div>
3914
3915<div class="doc_text">
3916
3917<h5>Syntax:</h5>
3918
3919<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3920 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3921</pre>
3922
3923<h5>Overview:</h5>
3924
3925<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3926locations, allowing garbage collector implementations that require read
3927barriers.</p>
3928
3929<h5>Arguments:</h5>
3930
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3931<p>The second argument is the address to read from, which should be an address
3932allocated from the garbage collector. The first object is a pointer to the
3933start of the referenced object, if needed by the language runtime (otherwise
3934null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3935
3936<h5>Semantics:</h5>
3937
3938<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3939instruction, but may be replaced with substantially more complex code by the
3940garbage collector runtime, as needed.</p>
3941
3942</div>
3943
3944
3945<!-- _______________________________________________________________________ -->
3946<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3947 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3948</div>
3949
3950<div class="doc_text">
3951
3952<h5>Syntax:</h5>
3953
3954<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3955 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3956</pre>
3957
3958<h5>Overview:</h5>
3959
3960<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3961locations, allowing garbage collector implementations that require write
3962barriers (such as generational or reference counting collectors).</p>
3963
3964<h5>Arguments:</h5>
3965
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3966<p>The first argument is the reference to store, the second is the start of the
3967object to store it to, and the third is the address of the field of Obj to
3968store to. If the runtime does not require a pointer to the object, Obj may be
3969null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3970
3971<h5>Semantics:</h5>
3972
3973<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3974instruction, but may be replaced with substantially more complex code by the
3975garbage collector runtime, as needed.</p>
3976
3977</div>
3978
3979
3980
3981<!-- ======================================================================= -->
3982<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3983 <a name="int_codegen">Code Generator Intrinsics</a>
3984</div>
3985
3986<div class="doc_text">
3987<p>
3988These intrinsics are provided by LLVM to expose special features that may only
3989be implemented with code generator support.
3990</p>
3991
3992</div>
3993
3994<!-- _______________________________________________________________________ -->
3995<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3996 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3997</div>
3998
3999<div class="doc_text">
4000
4001<h5>Syntax:</h5>
4002<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4003 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4004</pre>
4005
4006<h5>Overview:</h5>
4007
4008<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4009The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4010target-specific value indicating the return address of the current function
4011or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4012</p>
4013
4014<h5>Arguments:</h5>
4015
4016<p>
4017The argument to this intrinsic indicates which function to return the address
4018for. Zero indicates the calling function, one indicates its caller, etc. The
4019argument is <b>required</b> to be a constant integer value.
4020</p>
4021
4022<h5>Semantics:</h5>
4023
4024<p>
4025The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4026the return address of the specified call frame, or zero if it cannot be
4027identified. The value returned by this intrinsic is likely to be incorrect or 0
4028for arguments other than zero, so it should only be used for debugging purposes.
4029</p>
4030
4031<p>
4032Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4033aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4034source-language caller.
4035</p>
4036</div>
4037
4038
4039<!-- _______________________________________________________________________ -->
4040<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4041 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4042</div>
4043
4044<div class="doc_text">
4045
4046<h5>Syntax:</h5>
4047<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4048 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4049</pre>
4050
4051<h5>Overview:</h5>
4052
4053<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4054The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4055target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4056</p>
4057
4058<h5>Arguments:</h5>
4059
4060<p>
4061The argument to this intrinsic indicates which function to return the frame
4062pointer for. Zero indicates the calling function, one indicates its caller,
4063etc. The argument is <b>required</b> to be a constant integer value.
4064</p>
4065
4066<h5>Semantics:</h5>
4067
4068<p>
4069The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4070the frame address of the specified call frame, or zero if it cannot be
4071identified. The value returned by this intrinsic is likely to be incorrect or 0
4072for arguments other than zero, so it should only be used for debugging purposes.
4073</p>
4074
4075<p>
4076Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4077aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4078source-language caller.
4079</p>
4080</div>
4081
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4082<!-- _______________________________________________________________________ -->
4083<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4084 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4085</div>
4086
4087<div class="doc_text">
4088
4089<h5>Syntax:</h5>
4090<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4091 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4092</pre>
4093
4094<h5>Overview:</h5>
4095
4096<p>
4097The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4098the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4099<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4100features like scoped automatic variable sized arrays in C99.
4101</p>
4102
4103<h5>Semantics:</h5>
4104
4105<p>
4106This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4107href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4108<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4109<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4110state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4111practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4112that were allocated after the <tt>llvm.stacksave</tt> was executed.
4113</p>
4114
4115</div>
4116
4117<!-- _______________________________________________________________________ -->
4118<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4119 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4120</div>
4121
4122<div class="doc_text">
4123
4124<h5>Syntax:</h5>
4125<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4126 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4127</pre>
4128
4129<h5>Overview:</h5>
4130
4131<p>
4132The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4133the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4134href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4135useful for implementing language features like scoped automatic variable sized
4136arrays in C99.
4137</p>
4138
4139<h5>Semantics:</h5>
4140
4141<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4142See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4143</p>
4144
4145</div>
4146
4147
4148<!-- _______________________________________________________________________ -->
4149<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4150 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4151</div>
4152
4153<div class="doc_text">
4154
4155<h5>Syntax:</h5>
4156<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4157 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4158 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4159</pre>
4160
4161<h5>Overview:</h5>
4162
4163
4164<p>
4165The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4166a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4167no
4168effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4169characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4170</p>
4171
4172<h5>Arguments:</h5>
4173
4174<p>
4175<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4176determining if the fetch should be for a read (0) or write (1), and
4177<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4178locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4179<tt>locality</tt> arguments must be constant integers.
4180</p>
4181
4182<h5>Semantics:</h5>
4183
4184<p>
4185This intrinsic does not modify the behavior of the program. In particular,
4186prefetches cannot trap and do not produce a value. On targets that support this
4187intrinsic, the prefetch can provide hints to the processor cache for better
4188performance.
4189</p>
4190
4191</div>
4192
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4193<!-- _______________________________________________________________________ -->
4194<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4195 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4196</div>
4197
4198<div class="doc_text">
4199
4200<h5>Syntax:</h5>
4201<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4202 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4203</pre>
4204
4205<h5>Overview:</h5>
4206
4207
4208<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4209The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4210(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4211code to simulators and other tools. The method is target specific, but it is
4212expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4213The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4214after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4215optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4216correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4217</p>
4218
4219<h5>Arguments:</h5>
4220
4221<p>
4222<tt>id</tt> is a numerical id identifying the marker.
4223</p>
4224
4225<h5>Semantics:</h5>
4226
4227<p>
4228This intrinsic does not modify the behavior of the program. Backends that do not
4229support this intrinisic may ignore it.
4230</p>
4231
4232</div>
4233
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4234<!-- _______________________________________________________________________ -->
4235<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4236 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4237</div>
4238
4239<div class="doc_text">
4240
4241<h5>Syntax:</h5>
4242<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4243 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4244</pre>
4245
4246<h5>Overview:</h5>
4247
4248
4249<p>
4250The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4251counter register (or similar low latency, high accuracy clocks) on those targets
4252that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4253As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4254should only be used for small timings.
4255</p>
4256
4257<h5>Semantics:</h5>
4258
4259<p>
4260When directly supported, reading the cycle counter should not modify any memory.
4261Implementations are allowed to either return a application specific value or a
4262system wide value. On backends without support, this is lowered to a constant 0.
4263</p>
4264
4265</div>
4266
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4267<!-- ======================================================================= -->
4268<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4269 <a name="int_libc">Standard C Library Intrinsics</a>
4270</div>
4271
4272<div class="doc_text">
4273<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4274LLVM provides intrinsics for a few important standard C library functions.
4275These intrinsics allow source-language front-ends to pass information about the
4276alignment of the pointer arguments to the code generator, providing opportunity
4277for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4278</p>
4279
4280</div>
4281
4282<!-- _______________________________________________________________________ -->
4283<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4284 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4285</div>
4286
4287<div class="doc_text">
4288
4289<h5>Syntax:</h5>
4290<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4291 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4292 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4293 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4294 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4295</pre>
4296
4297<h5>Overview:</h5>
4298
4299<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4300The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4301location to the destination location.
4302</p>
4303
4304<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4305Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4306intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4307</p>
4308
4309<h5>Arguments:</h5>
4310
4311<p>
4312The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4313the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4314specifying the number of bytes to copy, and the fourth argument is the alignment
4315of the source and destination locations.
4316</p>
4317
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4318<p>
4319If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4320the caller guarantees that both the source and destination pointers are aligned
4321to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4322</p>
4323
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4324<h5>Semantics:</h5>
4325
4326<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4327The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4328location to the destination location, which are not allowed to overlap. It
4329copies "len" bytes of memory over. If the argument is known to be aligned to
4330some boundary, this can be specified as the fourth argument, otherwise it should
4331be set to 0 or 1.
4332</p>
4333</div>
4334
4335
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4336<!-- _______________________________________________________________________ -->
4337<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4338 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4339</div>
4340
4341<div class="doc_text">
4342
4343<h5>Syntax:</h5>
4344<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4345 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4346 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4347 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4348 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4349</pre>
4350
4351<h5>Overview:</h5>
4352
4353<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4354The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4355location to the destination location. It is similar to the
4356'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4357</p>
4358
4359<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4360Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4361intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4362</p>
4363
4364<h5>Arguments:</h5>
4365
4366<p>
4367The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4368the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4369specifying the number of bytes to copy, and the fourth argument is the alignment
4370of the source and destination locations.
4371</p>
4372
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4373<p>
4374If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4375the caller guarantees that the source and destination pointers are aligned to
4376that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4377</p>
4378
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4379<h5>Semantics:</h5>
4380
4381<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4382The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4383location to the destination location, which may overlap. It
4384copies "len" bytes of memory over. If the argument is known to be aligned to
4385some boundary, this can be specified as the fourth argument, otherwise it should
4386be set to 0 or 1.
4387</p>
4388</div>
4389
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4390
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4391<!-- _______________________________________________________________________ -->
4392<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4393 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4394</div>
4395
4396<div class="doc_text">
4397
4398<h5>Syntax:</h5>
4399<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4400 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4401 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4402 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4403 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4404</pre>
4405
4406<h5>Overview:</h5>
4407
4408<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4409The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4410byte value.
4411</p>
4412
4413<p>
4414Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4415does not return a value, and takes an extra alignment argument.
4416</p>
4417
4418<h5>Arguments:</h5>
4419
4420<p>
4421The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4422byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4423argument specifying the number of bytes to fill, and the fourth argument is the
4424known alignment of destination location.
4425</p>
4426
4427<p>
4428If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4429the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4430</p>
4431
4432<h5>Semantics:</h5>
4433
4434<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4435The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4436the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4437destination location. If the argument is known to be aligned to some boundary,
4438this can be specified as the fourth argument, otherwise it should be set to 0 or
44391.
4440</p>
4441</div>
4442
4443
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4444<!-- _______________________________________________________________________ -->
4445<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4446 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4447</div>
4448
4449<div class="doc_text">
4450
4451<h5>Syntax:</h5>
4452<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4453 declare float @llvm.sqrt.f32(float %Val)
4454 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4455</pre>
4456
4457<h5>Overview:</h5>
4458
4459<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4460The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4461returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4462<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4463negative numbers (which allows for better optimization).
4464</p>
4465
4466<h5>Arguments:</h5>
4467
4468<p>
4469The argument and return value are floating point numbers of the same type.
4470</p>
4471
4472<h5>Semantics:</h5>
4473
4474<p>
4475This function returns the sqrt of the specified operand if it is a positive
4476floating point number.
4477</p>
4478</div>
4479
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4480<!-- _______________________________________________________________________ -->
4481<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4482 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4483</div>
4484
4485<div class="doc_text">
4486
4487<h5>Syntax:</h5>
4488<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4489 declare float @llvm.powi.f32(float %Val, i32 %power)
4490 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4491</pre>
4492
4493<h5>Overview:</h5>
4494
4495<p>
4496The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4497specified (positive or negative) power. The order of evaluation of
4498multiplications is not defined.
4499</p>
4500
4501<h5>Arguments:</h5>
4502
4503<p>
4504The second argument is an integer power, and the first is a value to raise to
4505that power.
4506</p>
4507
4508<h5>Semantics:</h5>
4509
4510<p>
4511This function returns the first value raised to the second power with an
4512unspecified sequence of rounding operations.</p>
4513</div>
4514
4515
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4516<!-- ======================================================================= -->
4517<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4518 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4519</div>
4520
4521<div class="doc_text">
4522<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4523LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4524These allow efficient code generation for some algorithms.
4525</p>
4526
4527</div>
4528
4529<!-- _______________________________________________________________________ -->
4530<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4531 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4532</div>
4533
4534<div class="doc_text">
4535
4536<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4537<p>This is an overloaded intrinsic function. You can use bswap on any integer
4538type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4539that includes the type for the result and the operand.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4540<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4541 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4542 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer543ab1d2007-04-02 00:19:52 +0000[diff] [blame]4543 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4544</pre>
4545
4546<h5>Overview:</h5>
4547
4548<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4549The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4550values with an even number of bytes (positive multiple of 16 bits). These are
4551useful for performing operations on data that is not in the target's native
4552byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4553</p>
4554
4555<h5>Semantics:</h5>
4556
4557<p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4558The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4559and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4560intrinsic returns an i32 value that has the four bytes of the input i32
4561swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4562i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4563<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4564additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4565</p>
4566
4567</div>
4568
4569<!-- _______________________________________________________________________ -->
4570<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4571 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4572</div>
4573
4574<div class="doc_text">
4575
4576<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4577<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4578width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4579<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4580 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4581 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4582 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4583 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4584 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4585</pre>
4586
4587<h5>Overview:</h5>
4588
4589<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4590The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4591value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4592</p>
4593
4594<h5>Arguments:</h5>
4595
4596<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4597The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4598integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4599</p>
4600
4601<h5>Semantics:</h5>
4602
4603<p>
4604The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4605</p>
4606</div>
4607
4608<!-- _______________________________________________________________________ -->
4609<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4610 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4611</div>
4612
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4616<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4617integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4618<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4619 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4620 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4621 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4622 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4623 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4624</pre>
4625
4626<h5>Overview:</h5>
4627
4628<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4629The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4630leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4631</p>
4632
4633<h5>Arguments:</h5>
4634
4635<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4636The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4637integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4638</p>
4639
4640<h5>Semantics:</h5>
4641
4642<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4643The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4644in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4645of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4646</p>
4647</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4648
4649
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4650
4651<!-- _______________________________________________________________________ -->
4652<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4653 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4654</div>
4655
4656<div class="doc_text">
4657
4658<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4659<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4660integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4661<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4662 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4663 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4664 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4665 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4666 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4667</pre>
4668
4669<h5>Overview:</h5>
4670
4671<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4672The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4673trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4674</p>
4675
4676<h5>Arguments:</h5>
4677
4678<p>
4679The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4680integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4681</p>
4682
4683<h5>Semantics:</h5>
4684
4685<p>
4686The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4687in a variable. If the src == 0 then the result is the size in bits of the type
4688of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4689</p>
4690</div>
4691
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4692<!-- _______________________________________________________________________ -->
4693<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4694 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4695</div>
4696
4697<div class="doc_text">
4698
4699<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4700<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4701on any integer bit width.
4702<pre>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4703 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4704 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4705</pre>
4706
4707<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4708<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4709range of bits from an integer value and returns them in the same bit width as
4710the original value.</p>
4711
4712<h5>Arguments:</h5>
4713<p>The first argument, <tt>%val</tt> and the result may be integer types of
4714any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4715arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4716
4717<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4718<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4719of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4720<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4721operates in forward mode.</p>
4722<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4723right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4724only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4725<ol>
4726 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4727 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4728 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4729 to determine the number of bits to retain.</li>
4730 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4731 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4732</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]4733<p>In reverse mode, a similar computation is made except that the bits are
4734returned in the reverse order. So, for example, if <tt>X</tt> has the value
4735<tt>i16 0x0ACF (101011001111)</tt> and we apply
4736<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4737<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4738</div>
4739
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4740<div class="doc_subsubsection">
4741 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4742</div>
4743
4744<div class="doc_text">
4745
4746<h5>Syntax:</h5>
4747<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4748on any integer bit width.
4749<pre>
4750 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4751 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4752</pre>
4753
4754<h5>Overview:</h5>
4755<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4756of bits in an integer value with another integer value. It returns the integer
4757with the replaced bits.</p>
4758
4759<h5>Arguments:</h5>
4760<p>The first argument, <tt>%val</tt> and the result may be integer types of
4761any bit width but they must have the same bit width. <tt>%val</tt> is the value
4762whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4763integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4764type since they specify only a bit index.</p>
4765
4766<h5>Semantics:</h5>
4767<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4768of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4769<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4770operates in forward mode.</p>
4771<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4772truncating it down to the size of the replacement area or zero extending it
4773up to that size.</p>
4774<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4775are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4776in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4777to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4778<p>In reverse mode, a similar computation is made except that the bits are
4779reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4780<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4781<h5>Examples:</h5>
4782<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4783 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4784 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4785 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4786 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4787 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4788</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4789</div>
4790
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4791<!-- ======================================================================= -->
4792<div class="doc_subsection">
4793 <a name="int_debugger">Debugger Intrinsics</a>
4794</div>
4795
4796<div class="doc_text">
4797<p>
4798The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4799are described in the <a
4800href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4801Debugging</a> document.
4802</p>
4803</div>
4804
4805
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4806<!-- ======================================================================= -->
4807<div class="doc_subsection">
4808 <a name="int_eh">Exception Handling Intrinsics</a>
4809</div>
4810
4811<div class="doc_text">
4812<p> The LLVM exception handling intrinsics (which all start with
4813<tt>llvm.eh.</tt> prefix), are described in the <a
4814href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4815Handling</a> document. </p>
4816</div>
4817
4818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4819<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4820<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4821<address>
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4826
4827 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4828 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4829 Last modified: $Date$
4830</address>
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