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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 8c6c72d0bae4f2a2cf28a45fb3bc4bb44e15001f / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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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>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]180 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
181 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]183 </ol>
184 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]185 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]186 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]187 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]188 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
190 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]191 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
192 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]193 </ol>
194 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]195 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]196 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]197 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]198 <ol>
199 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]200 </ol>
201 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]202 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]203 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]204 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]205 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]206 </ol>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]207 <ol>
208 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]209 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]210 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]211 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]214</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
216<div class="doc_author">
217 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
218 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]219</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]221<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<div class="doc_section"> <a name="abstract">Abstract </a></div>
223<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]225<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]226<p>This document is a reference manual for the LLVM assembly language.
227LLVM is an SSA based representation that provides type safety,
228low-level operations, flexibility, and the capability of representing
229'all' high-level languages cleanly. It is the common code
230representation used throughout all phases of the LLVM compilation
231strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]232</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]234<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]235<div class="doc_section"> <a name="introduction">Introduction</a> </div>
236<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]238<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]241different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]242representation (suitable for fast loading by a Just-In-Time compiler),
243and as a human readable assembly language representation. This allows
244LLVM to provide a powerful intermediate representation for efficient
245compiler transformations and analysis, while providing a natural means
246to debug and visualize the transformations. The three different forms
247of LLVM are all equivalent. This document describes the human readable
248representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]250<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]251while being expressive, typed, and extensible at the same time. It
252aims to be a "universal IR" of sorts, by being at a low enough level
253that high-level ideas may be cleanly mapped to it (similar to how
254microprocessors are "universal IR's", allowing many source languages to
255be mapped to them). By providing type information, LLVM can be used as
256the target of optimizations: for example, through pointer analysis, it
257can be proven that a C automatic variable is never accessed outside of
258the current function... allowing it to be promoted to a simple SSA
259value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]260
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]261</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]262
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]263<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]264<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]266<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]268<p>It is important to note that this document describes 'well formed'
269LLVM assembly language. There is a difference between what the parser
270accepts and what is considered 'well formed'. For example, the
271following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]273<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]275%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]276</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]277</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]278
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]279<p>...because the definition of <tt>%x</tt> does not dominate all of
280its uses. The LLVM infrastructure provides a verification pass that may
281be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]282automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]283the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]284by the verifier pass indicate bugs in transformation passes or input to
285the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]286</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]287
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]288<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]289
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]290<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]291<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]292<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]293
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]294<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]295
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]296 <p>LLVM identifiers come in two basic types: global and local. Global
297 identifiers (functions, global variables) begin with the @ character. Local
298 identifiers (register names, types) begin with the % character. Additionally,
299 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]301<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]302 <li>Named values are represented as a string of characters with their prefix.
303 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
304 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]305 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]306 with quotes. In this way, anything except a <tt>&quot;</tt> character can
307 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]308
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]309 <li>Unnamed values are represented as an unsigned numeric value with their
310 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]311
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]312 <li>Constants, which are described in a <a href="#constants">section about
313 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]314</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]316<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317don't need to worry about name clashes with reserved words, and the set of
318reserved words may be expanded in the future without penalty. Additionally,
319unnamed identifiers allow a compiler to quickly come up with a temporary
320variable without having to avoid symbol table conflicts.</p>
321
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]323languages. There are keywords for different opcodes
324('<tt><a href="#i_add">add</a></tt>',
325 '<tt><a href="#i_bitcast">bitcast</a></tt>',
326 '<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]327href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]328and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]329none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]330
331<p>Here is an example of LLVM code to multiply the integer variable
332'<tt>%X</tt>' by 8:</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]336<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]337<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]338%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]339</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]340</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]341
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]342<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]344<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]346%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]347</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]348</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]349
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]350<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]351
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]352<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]353<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]354<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
355<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
356%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]357</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]359
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]360<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
361important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]363<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]364
365 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
366 line.</li>
367
368 <li>Unnamed temporaries are created when the result of a computation is not
369 assigned to a named value.</li>
370
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]371 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]372
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]373</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]374
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]375<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]376demonstrating instructions, we will follow an instruction with a comment that
377defines the type and name of value produced. Comments are shown in italic
378text.</p>
379
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]380</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]381
382<!-- *********************************************************************** -->
383<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
384<!-- *********************************************************************** -->
385
386<!-- ======================================================================= -->
387<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
388</div>
389
390<div class="doc_text">
391
392<p>LLVM programs are composed of "Module"s, each of which is a
393translation unit of the input programs. Each module consists of
394functions, global variables, and symbol table entries. Modules may be
395combined together with the LLVM linker, which merges function (and
396global variable) definitions, resolves forward declarations, and merges
397symbol table entries. Here is an example of the "hello world" module:</p>
398
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]399<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]400<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]401<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
402 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]403
404<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]405<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]406
407<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]408define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]409 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]410 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]411 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]412
413 <i>; Call puts function to write out the string to stdout...</i>
414 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]415 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]416 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]417 href="#i_ret">ret</a> i32 0<br>}<br>
418</pre>
419</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420
421<p>This example is made up of a <a href="#globalvars">global variable</a>
422named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
423function, and a <a href="#functionstructure">function definition</a>
424for "<tt>main</tt>".</p>
425
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426<p>In general, a module is made up of a list of global values,
427where both functions and global variables are global values. Global values are
428represented by a pointer to a memory location (in this case, a pointer to an
429array of char, and a pointer to a function), and have one of the following <a
430href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]431
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432</div>
433
434<!-- ======================================================================= -->
435<div class="doc_subsection">
436 <a name="linkage">Linkage Types</a>
437</div>
438
439<div class="doc_text">
440
441<p>
442All Global Variables and Functions have one of the following types of linkage:
443</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]444
445<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]447 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
449 <dd>Global values with internal linkage are only directly accessible by
450 objects in the current module. In particular, linking code into a module with
451 an internal global value may cause the internal to be renamed as necessary to
452 avoid collisions. Because the symbol is internal to the module, all
453 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]454 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]455 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]457 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]459 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
460 the same name when linkage occurs. This is typically used to implement
461 inline functions, templates, or other code which must be generated in each
462 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
463 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]464 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]466 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
468 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
469 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]470 used for globals that may be emitted in multiple translation units, but that
471 are not guaranteed to be emitted into every translation unit that uses them.
472 One example of this are common globals in C, such as "<tt>int X;</tt>" at
473 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]474 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]477
478 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
479 pointer to array type. When two global variables with appending linkage are
480 linked together, the two global arrays are appended together. This is the
481 LLVM, typesafe, equivalent of having the system linker append together
482 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]484
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]485 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
486 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
487 until linked, if not linked, the symbol becomes null instead of being an
488 undefined reference.
489 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]490
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]492
493 <dd>If none of the above identifiers are used, the global is externally
494 visible, meaning that it participates in linkage and can be used to resolve
495 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]497</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]498
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]499 <p>
500 The next two types of linkage are targeted for Microsoft Windows platform
501 only. They are designed to support importing (exporting) symbols from (to)
502 DLLs.
503 </p>
504
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]505 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]506 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
507
508 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
509 or variable via a global pointer to a pointer that is set up by the DLL
510 exporting the symbol. On Microsoft Windows targets, the pointer name is
511 formed by combining <code>_imp__</code> and the function or variable name.
512 </dd>
513
514 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
515
516 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
517 pointer to a pointer in a DLL, so that it can be referenced with the
518 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
519 name is formed by combining <code>_imp__</code> and the function or variable
520 name.
521 </dd>
522
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523</dl>
524
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]525<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]526variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
527variable and was linked with this one, one of the two would be renamed,
528preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
529external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]530outside of the current module.</p>
531<p>It is illegal for a function <i>declaration</i>
532to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]533or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]534<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
535linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]540 <a name="callingconv">Calling Conventions</a>
541</div>
542
543<div class="doc_text">
544
545<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
546and <a href="#i_invoke">invokes</a> can all have an optional calling convention
547specified for the call. The calling convention of any pair of dynamic
548caller/callee must match, or the behavior of the program is undefined. The
549following calling conventions are supported by LLVM, and more may be added in
550the future:</p>
551
552<dl>
553 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
554
555 <dd>This calling convention (the default if no other calling convention is
556 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]557 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]558 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]559 </dd>
560
561 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
562
563 <dd>This calling convention attempts to make calls as fast as possible
564 (e.g. by passing things in registers). This calling convention allows the
565 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]566 without having to conform to an externally specified ABI. Implementations of
567 this convention should allow arbitrary tail call optimization to be supported.
568 This calling convention does not support varargs and requires the prototype of
569 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]570 </dd>
571
572 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
573
574 <dd>This calling convention attempts to make code in the caller as efficient
575 as possible under the assumption that the call is not commonly executed. As
576 such, these calls often preserve all registers so that the call does not break
577 any live ranges in the caller side. This calling convention does not support
578 varargs and requires the prototype of all callees to exactly match the
579 prototype of the function definition.
580 </dd>
581
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]582 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]583
584 <dd>Any calling convention may be specified by number, allowing
585 target-specific calling conventions to be used. Target specific calling
586 conventions start at 64.
587 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]588</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]589
590<p>More calling conventions can be added/defined on an as-needed basis, to
591support pascal conventions or any other well-known target-independent
592convention.</p>
593
594</div>
595
596<!-- ======================================================================= -->
597<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]598 <a name="visibility">Visibility Styles</a>
599</div>
600
601<div class="doc_text">
602
603<p>
604All Global Variables and Functions have one of the following visibility styles:
605</p>
606
607<dl>
608 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
609
610 <dd>On ELF, default visibility means that the declaration is visible to other
611 modules and, in shared libraries, means that the declared entity may be
612 overridden. On Darwin, default visibility means that the declaration is
613 visible to other modules. Default visibility corresponds to "external
614 linkage" in the language.
615 </dd>
616
617 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
618
619 <dd>Two declarations of an object with hidden visibility refer to the same
620 object if they are in the same shared object. Usually, hidden visibility
621 indicates that the symbol will not be placed into the dynamic symbol table,
622 so no other module (executable or shared library) can reference it
623 directly.
624 </dd>
625
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]626 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
627
628 <dd>On ELF, protected visibility indicates that the symbol will be placed in
629 the dynamic symbol table, but that references within the defining module will
630 bind to the local symbol. That is, the symbol cannot be overridden by another
631 module.
632 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]633</dl>
634
635</div>
636
637<!-- ======================================================================= -->
638<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]639 <a name="globalvars">Global Variables</a>
640</div>
641
642<div class="doc_text">
643
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]644<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]645instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]646an explicit section to be placed in, and may have an optional explicit alignment
647specified. A variable may be defined as "thread_local", which means that it
648will not be shared by threads (each thread will have a separated copy of the
649variable). A variable may be defined as a global "constant," which indicates
650that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]651optimization, allowing the global data to be placed in the read-only section of
652an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]653cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]654
655<p>
656LLVM explicitly allows <em>declarations</em> of global variables to be marked
657constant, even if the final definition of the global is not. This capability
658can be used to enable slightly better optimization of the program, but requires
659the language definition to guarantee that optimizations based on the
660'constantness' are valid for the translation units that do not include the
661definition.
662</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]663
664<p>As SSA values, global variables define pointer values that are in
665scope (i.e. they dominate) all basic blocks in the program. Global
666variables always define a pointer to their "content" type because they
667describe a region of memory, and all memory objects in LLVM are
668accessed through pointers.</p>
669
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]670<p>LLVM allows an explicit section to be specified for globals. If the target
671supports it, it will emit globals to the section specified.</p>
672
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]673<p>An explicit alignment may be specified for a global. If not present, or if
674the alignment is set to zero, the alignment of the global is set by the target
675to whatever it feels convenient. If an explicit alignment is specified, the
676global is forced to have at least that much alignment. All alignments must be
677a power of 2.</p>
678
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]679<p>For example, the following defines a global with an initializer, section,
680 and alignment:</p>
681
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]682<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]683<pre>
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]684@G = constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]685</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]686</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]687
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]688</div>
689
690
691<!-- ======================================================================= -->
692<div class="doc_subsection">
693 <a name="functionstructure">Functions</a>
694</div>
695
696<div class="doc_text">
697
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]698<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
699an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]700<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]701<a href="#callingconv">calling convention</a>, a return type, an optional
702<a href="#paramattrs">parameter attribute</a> for the return type, a function
703name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]704<a href="#paramattrs">parameter attributes</a>), an optional section, an
705optional alignment, an opening curly brace, a list of basic blocks, and a
706closing curly brace.
707
708LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
709optional <a href="#linkage">linkage type</a>, an optional
710<a href="#visibility">visibility style</a>, an optional
711<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]712<a href="#paramattrs">parameter attribute</a> for the return type, a function
713name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]714
715<p>A function definition contains a list of basic blocks, forming the CFG for
716the function. Each basic block may optionally start with a label (giving the
717basic block a symbol table entry), contains a list of instructions, and ends
718with a <a href="#terminators">terminator</a> instruction (such as a branch or
719function return).</p>
720
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]721<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]722executed on entrance to the function, and it is not allowed to have predecessor
723basic blocks (i.e. there can not be any branches to the entry block of a
724function). Because the block can have no predecessors, it also cannot have any
725<a href="#i_phi">PHI nodes</a>.</p>
726
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]727<p>LLVM allows an explicit section to be specified for functions. If the target
728supports it, it will emit functions to the section specified.</p>
729
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]730<p>An explicit alignment may be specified for a function. If not present, or if
731the alignment is set to zero, the alignment of the function is set by the target
732to whatever it feels convenient. If an explicit alignment is specified, the
733function is forced to have at least that much alignment. All alignments must be
734a power of 2.</p>
735
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]736</div>
737
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]738
739<!-- ======================================================================= -->
740<div class="doc_subsection">
741 <a name="aliasstructure">Aliases</a>
742</div>
743<div class="doc_text">
744 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]745 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]746 optional <a href="#linkage">linkage type</a>, and an
747 optional <a href="#visibility">visibility style</a>.</p>
748
749 <h5>Syntax:</h5>
750
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]751<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]752<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]753@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]754</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]755</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]756
757</div>
758
759
760
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]761<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]762<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
763<div class="doc_text">
764 <p>The return type and each parameter of a function type may have a set of
765 <i>parameter attributes</i> associated with them. Parameter attributes are
766 used to communicate additional information about the result or parameters of
767 a function. Parameter attributes are considered to be part of the function
768 type so two functions types that differ only by the parameter attributes
769 are different function types.</p>
770
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]771 <p>Parameter attributes are simple keywords that follow the type specified. If
772 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]773 example:</p>
774
775<div class="doc_code">
776<pre>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]777%someFunc = i16 (i8 signext %someParam) zeroext
778%someFunc = i16 (i8 zeroext %someParam) zeroext
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]779</pre>
780</div>
781
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]782 <p>Note that the two function types above are unique because the parameter has
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]783 a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
784 the second). Also note that the attribute for the function result
785 (<tt>zeroext</tt>) comes immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]786
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]787 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]788 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]789 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]790 <dd>This indicates that the parameter should be zero extended just before
791 a call to this function.</dd>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]792 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]793 <dd>This indicates that the parameter should be sign extended just before
794 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]795 <dt><tt>inreg</tt></dt>
796 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]797 possible) during assembling function call. Support for this attribute is
798 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]799 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]800 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]801 that is the return value of the function in the source program.</dd>
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]802 <dt><tt>noalias</tt></dt>
803 <dd>This indicates that the parameter not alias any other object or any
804 other "noalias" objects during the function call.
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]805 <dt><tt>noreturn</tt></dt>
806 <dd>This function attribute indicates that the function never returns. This
807 indicates to LLVM that every call to this function should be treated as if
808 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]809 <dt><tt>nounwind</tt></dt>
810 <dd>This function attribute indicates that the function type does not use
811 the unwind instruction and does not allow stack unwinding to propagate
812 through it.</dd>
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]813 <dt><tt>nest</tt></dt>
814 <dd>This indicates that the parameter can be excised using the
815 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]816 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]817
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]818</div>
819
820<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]821<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]822 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]823</div>
824
825<div class="doc_text">
826<p>
827Modules may contain "module-level inline asm" blocks, which corresponds to the
828GCC "file scope inline asm" blocks. These blocks are internally concatenated by
829LLVM and treated as a single unit, but may be separated in the .ll file if
830desired. The syntax is very simple:
831</p>
832
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]833<div class="doc_code">
834<pre>
835module asm "inline asm code goes here"
836module asm "more can go here"
837</pre>
838</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]839
840<p>The strings can contain any character by escaping non-printable characters.
841 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
842 for the number.
843</p>
844
845<p>
846 The inline asm code is simply printed to the machine code .s file when
847 assembly code is generated.
848</p>
849</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]851<!-- ======================================================================= -->
852<div class="doc_subsection">
853 <a name="datalayout">Data Layout</a>
854</div>
855
856<div class="doc_text">
857<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]858data is to be laid out in memory. The syntax for the data layout is simply:</p>
859<pre> target datalayout = "<i>layout specification</i>"</pre>
860<p>The <i>layout specification</i> consists of a list of specifications
861separated by the minus sign character ('-'). Each specification starts with a
862letter and may include other information after the letter to define some
863aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]864<dl>
865 <dt><tt>E</tt></dt>
866 <dd>Specifies that the target lays out data in big-endian form. That is, the
867 bits with the most significance have the lowest address location.</dd>
868 <dt><tt>e</tt></dt>
869 <dd>Specifies that hte target lays out data in little-endian form. That is,
870 the bits with the least significance have the lowest address location.</dd>
871 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
872 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
873 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
874 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
875 too.</dd>
876 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
877 <dd>This specifies the alignment for an integer type of a given bit
878 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
879 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
880 <dd>This specifies the alignment for a vector type of a given bit
881 <i>size</i>.</dd>
882 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
883 <dd>This specifies the alignment for a floating point type of a given bit
884 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
885 (double).</dd>
886 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
887 <dd>This specifies the alignment for an aggregate type of a given bit
888 <i>size</i>.</dd>
889</dl>
890<p>When constructing the data layout for a given target, LLVM starts with a
891default set of specifications which are then (possibly) overriden by the
892specifications in the <tt>datalayout</tt> keyword. The default specifications
893are given in this list:</p>
894<ul>
895 <li><tt>E</tt> - big endian</li>
896 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
897 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
898 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
899 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
900 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
901 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
902 alignment of 64-bits</li>
903 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
904 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
905 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
906 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
907 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
908</ul>
909<p>When llvm is determining the alignment for a given type, it uses the
910following rules:
911<ol>
912 <li>If the type sought is an exact match for one of the specifications, that
913 specification is used.</li>
914 <li>If no match is found, and the type sought is an integer type, then the
915 smallest integer type that is larger than the bitwidth of the sought type is
916 used. If none of the specifications are larger than the bitwidth then the the
917 largest integer type is used. For example, given the default specifications
918 above, the i7 type will use the alignment of i8 (next largest) while both
919 i65 and i256 will use the alignment of i64 (largest specified).</li>
920 <li>If no match is found, and the type sought is a vector type, then the
921 largest vector type that is smaller than the sought vector type will be used
922 as a fall back. This happens because <128 x double> can be implemented in
923 terms of 64 <2 x double>, for example.</li>
924</ol>
925</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]927<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]928<div class="doc_section"> <a name="typesystem">Type System</a> </div>
929<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]930
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]931<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]932
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]933<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934intermediate representation. Being typed enables a number of
935optimizations to be performed on the IR directly, without having to do
936extra analyses on the side before the transformation. A strong type
937system makes it easier to read the generated code and enables novel
938analyses and transformations that are not feasible to perform on normal
939three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]940
941</div>
942
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]943<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]944<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]945<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]946<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]947system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]948
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]949<table class="layout">
950 <tr class="layout">
951 <td class="left">
952 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]953 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]954 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]955 <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]956 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]957 </tbody>
958 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]959 </td>
960 <td class="right">
961 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]962 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]963 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]964 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]965 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]966 </tbody>
967 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]968 </td>
969 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]970</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]971</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]973<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]974<div class="doc_subsubsection"> <a name="t_classifications">Type
975Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]976<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]977<p>These different primitive types fall into a few useful
978classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]979
980<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]981 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]982 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]983 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]984 <td><a name="t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]985 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]986 </tr>
987 <tr>
988 <td><a name="t_floating">floating point</a></td>
989 <td><tt>float, double</tt></td>
990 </tr>
991 <tr>
992 <td><a name="t_firstclass">first class</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]993 <td><tt>i1, ..., float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]994 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]995 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]996 </tr>
997 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]998</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]999
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1000<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1001most important. Values of these types are the only ones which can be
1002produced by instructions, passed as arguments, or used as operands to
1003instructions. This means that all structures and arrays must be
1004manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1005</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1007<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1008<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1009
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1010<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1011
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1012<p>The real power in LLVM comes from the derived types in the system.
1013This is what allows a programmer to represent arrays, functions,
1014pointers, and other useful types. Note that these derived types may be
1015recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1016
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1017</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1018
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1019<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1020<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1021
1022<div class="doc_text">
1023
1024<h5>Overview:</h5>
1025<p>The integer type is a very simple derived type that simply specifies an
1026arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10272^23-1 (about 8 million) can be specified.</p>
1028
1029<h5>Syntax:</h5>
1030
1031<pre>
1032 iN
1033</pre>
1034
1035<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1036value.</p>
1037
1038<h5>Examples:</h5>
1039<table class="layout">
1040 <tr class="layout">
1041 <td class="left">
1042 <tt>i1</tt><br/>
1043 <tt>i4</tt><br/>
1044 <tt>i8</tt><br/>
1045 <tt>i16</tt><br/>
1046 <tt>i32</tt><br/>
1047 <tt>i42</tt><br/>
1048 <tt>i64</tt><br/>
1049 <tt>i1942652</tt><br/>
1050 </td>
1051 <td class="left">
1052 A boolean integer of 1 bit<br/>
1053 A nibble sized integer of 4 bits.<br/>
1054 A byte sized integer of 8 bits.<br/>
1055 A half word sized integer of 16 bits.<br/>
1056 A word sized integer of 32 bits.<br/>
1057 An integer whose bit width is the answer. <br/>
1058 A double word sized integer of 64 bits.<br/>
1059 A really big integer of over 1 million bits.<br/>
1060 </td>
1061 </tr>
1062</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1063</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1064
1065<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1066<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1067
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1068<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1069
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1070<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1071
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1072<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1073sequentially in memory. The array type requires a size (number of
1074elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1075
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1076<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1077
1078<pre>
1079 [&lt;# elements&gt; x &lt;elementtype&gt;]
1080</pre>
1081
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1082<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1083be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1084
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1085<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1086<table class="layout">
1087 <tr class="layout">
1088 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1089 <tt>[40 x i32 ]</tt><br/>
1090 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1091 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1092 </td>
1093 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1094 Array of 40 32-bit integer values.<br/>
1095 Array of 41 32-bit integer values.<br/>
1096 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1097 </td>
1098 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1099</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1100<p>Here are some examples of multidimensional arrays:</p>
1101<table class="layout">
1102 <tr class="layout">
1103 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1104 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1105 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1106 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1107 </td>
1108 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1109 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1110 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1111 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1112 </td>
1113 </tr>
1114</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1115
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1116<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1117length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1118LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1119As a special case, however, zero length arrays are recognized to be variable
1120length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1121type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1122
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1123</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1125<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1126<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1127<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1128<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1129<p>The function type can be thought of as a function signature. It
1130consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1131Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1132(which are structures of pointers to functions), for indirect function
1133calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1134<p>
1135The return type of a function type cannot be an aggregate type.
1136</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1137<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1138<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1139<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]1140specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1141which indicates that the function takes a variable number of arguments.
1142Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1143 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1144<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1145<table class="layout">
1146 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1147 <td class="left"><tt>i32 (i32)</tt></td>
1148 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1149 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1150 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1151 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1152 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1153 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1154 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1155 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1156 <tt>float</tt>.
1157 </td>
1158 </tr><tr class="layout">
1159 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1160 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1161 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1162 which returns an integer. This is the signature for <tt>printf</tt> in
1163 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1164 </td>
1165 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1166</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1168</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1169<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1170<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1171<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1172<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1173<p>The structure type is used to represent a collection of data members
1174together in memory. The packing of the field types is defined to match
1175the ABI of the underlying processor. The elements of a structure may
1176be any type that has a size.</p>
1177<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1178and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1179field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1180instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1181<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1182<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1183<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1184<table class="layout">
1185 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1186 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1187 <td class="left">A triple of three <tt>i32</tt> values</td>
1188 </tr><tr class="layout">
1189 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1190 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1191 second element is a <a href="#t_pointer">pointer</a> to a
1192 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1193 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1194 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1195</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1196</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1197
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1198<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1199<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1200</div>
1201<div class="doc_text">
1202<h5>Overview:</h5>
1203<p>The packed structure type is used to represent a collection of data members
1204together in memory. There is no padding between fields. Further, the alignment
1205of a packed structure is 1 byte. The elements of a packed structure may
1206be any type that has a size.</p>
1207<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1208and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1209field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1210instruction.</p>
1211<h5>Syntax:</h5>
1212<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1213<h5>Examples:</h5>
1214<table class="layout">
1215 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1216 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1217 <td class="left">A triple of three <tt>i32</tt> values</td>
1218 </tr><tr class="layout">
1219 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1220 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1221 second element is a <a href="#t_pointer">pointer</a> to a
1222 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1223 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1224 </tr>
1225</table>
1226</div>
1227
1228<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1229<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1230<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1231<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1232<p>As in many languages, the pointer type represents a pointer or
1233reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1234<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1235<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1236<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1237<table class="layout">
1238 <tr class="layout">
1239 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1240 <tt>[4x i32]*</tt><br/>
1241 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1242 </td>
1243 <td class="left">
1244 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]1245 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1246 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1247 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1248 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1249 </td>
1250 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1251</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1252</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1253
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1254<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1255<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1256<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1257
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1258<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1259
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1260<p>A vector type is a simple derived type that represents a vector
1261of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1262are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1263A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1264elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1265of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1266considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1267
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1268<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1269
1270<pre>
1271 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1272</pre>
1273
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1274<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1275be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1276
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1277<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1278
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1279<table class="layout">
1280 <tr class="layout">
1281 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1282 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1283 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1284 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1285 </td>
1286 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1287 Vector of 4 32-bit integer values.<br/>
1288 Vector of 8 floating-point values.<br/>
1289 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1290 </td>
1291 </tr>
1292</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1293</div>
1294
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1295<!-- _______________________________________________________________________ -->
1296<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1297<div class="doc_text">
1298
1299<h5>Overview:</h5>
1300
1301<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1302corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1303In LLVM, opaque types can eventually be resolved to any type (not just a
1304structure type).</p>
1305
1306<h5>Syntax:</h5>
1307
1308<pre>
1309 opaque
1310</pre>
1311
1312<h5>Examples:</h5>
1313
1314<table class="layout">
1315 <tr class="layout">
1316 <td class="left">
1317 <tt>opaque</tt>
1318 </td>
1319 <td class="left">
1320 An opaque type.<br/>
1321 </td>
1322 </tr>
1323</table>
1324</div>
1325
1326
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1327<!-- *********************************************************************** -->
1328<div class="doc_section"> <a name="constants">Constants</a> </div>
1329<!-- *********************************************************************** -->
1330
1331<div class="doc_text">
1332
1333<p>LLVM has several different basic types of constants. This section describes
1334them all and their syntax.</p>
1335
1336</div>
1337
1338<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1339<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1340
1341<div class="doc_text">
1342
1343<dl>
1344 <dt><b>Boolean constants</b></dt>
1345
1346 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1347 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1348 </dd>
1349
1350 <dt><b>Integer constants</b></dt>
1351
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1352 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1353 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1354 integer types.
1355 </dd>
1356
1357 <dt><b>Floating point constants</b></dt>
1358
1359 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1360 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1361 notation (see below). Floating point constants must have a <a
1362 href="#t_floating">floating point</a> type. </dd>
1363
1364 <dt><b>Null pointer constants</b></dt>
1365
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1366 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1367 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1368
1369</dl>
1370
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1371<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372of floating point constants. For example, the form '<tt>double
13730x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13744.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1375(and the only time that they are generated by the disassembler) is when a
1376floating point constant must be emitted but it cannot be represented as a
1377decimal floating point number. For example, NaN's, infinities, and other
1378special values are represented in their IEEE hexadecimal format so that
1379assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1380
1381</div>
1382
1383<!-- ======================================================================= -->
1384<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1385</div>
1386
1387<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1388<p>Aggregate constants arise from aggregation of simple constants
1389and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1390
1391<dl>
1392 <dt><b>Structure constants</b></dt>
1393
1394 <dd>Structure constants are represented with notation similar to structure
1395 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1396 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
Chris Lattner3e63a9d2007-07-13 20:01:46 +0000[diff] [blame]1397 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]1398 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1399 types of elements must match those specified by the type.
1400 </dd>
1401
1402 <dt><b>Array constants</b></dt>
1403
1404 <dd>Array constants are represented with notation similar to array type
1405 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1406 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1407 constants must have <a href="#t_array">array type</a>, and the number and
1408 types of elements must match those specified by the type.
1409 </dd>
1410
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1411 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1412
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1413 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1414 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1415 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]1416 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1417 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1418 match those specified by the type.
1419 </dd>
1420
1421 <dt><b>Zero initialization</b></dt>
1422
1423 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1424 value to zero of <em>any</em> type, including scalar and aggregate types.
1425 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]1426 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427 initializers.
1428 </dd>
1429</dl>
1430
1431</div>
1432
1433<!-- ======================================================================= -->
1434<div class="doc_subsection">
1435 <a name="globalconstants">Global Variable and Function Addresses</a>
1436</div>
1437
1438<div class="doc_text">
1439
1440<p>The addresses of <a href="#globalvars">global variables</a> and <a
1441href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1442constants. These constants are explicitly referenced when the <a
1443href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1444href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1445file:</p>
1446
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1447<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1448<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1449@X = global i32 17
1450@Y = global i32 42
1451@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1452</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1453</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1454
1455</div>
1456
1457<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1458<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1459<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1460 <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]1461 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1462 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1463
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1464 <p>Undefined values indicate to the compiler that the program is well defined
1465 no matter what value is used, giving the compiler more freedom to optimize.
1466 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467</div>
1468
1469<!-- ======================================================================= -->
1470<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1471</div>
1472
1473<div class="doc_text">
1474
1475<p>Constant expressions are used to allow expressions involving other constants
1476to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1477href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1478that does not have side effects (e.g. load and call are not supported). The
1479following is the syntax for constant expressions:</p>
1480
1481<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1482 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1483 <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]1484 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1485
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1486 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1487 <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]1488 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]1489
1490 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1491 <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]1492 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]1493
1494 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1495 <dd>Truncate a floating point constant to another floating point type. The
1496 size of CST must be larger than the size of TYPE. Both types must be
1497 floating point.</dd>
1498
1499 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1500 <dd>Floating point extend a constant to another type. The size of CST must be
1501 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1502
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1503 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1504 <dd>Convert a floating point constant to the corresponding unsigned integer
1505 constant. TYPE must be an integer type. CST must be floating point. If the
1506 value won't fit in the integer type, the results are undefined.</dd>
1507
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1508 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1509 <dd>Convert a floating point constant to the corresponding signed integer
1510 constant. TYPE must be an integer type. CST must be floating point. If the
1511 value won't fit in the integer type, the results are undefined.</dd>
1512
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1513 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1514 <dd>Convert an unsigned integer constant to the corresponding floating point
1515 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1516 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1517
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1518 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1519 <dd>Convert a signed integer constant to the corresponding floating point
1520 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1521 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1522
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1523 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1524 <dd>Convert a pointer typed constant to the corresponding integer constant
1525 TYPE must be an integer type. CST must be of pointer type. The CST value is
1526 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1527
1528 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1529 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1530 pointer type. CST must be of integer type. The CST value is zero extended,
1531 truncated, or unchanged to make it fit in a pointer size. This one is
1532 <i>really</i> dangerous!</dd>
1533
1534 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1535 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1536 identical (same number of bits). The conversion is done as if the CST value
1537 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]1538 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1539 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]1540 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1541 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1542
1543 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1544
1545 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1546 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1547 instruction, the index list may have zero or more indexes, which are required
1548 to make sense for the type of "CSTPTR".</dd>
1549
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1550 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1551
1552 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1553 constants.</dd>
1554
1555 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1556 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1557
1558 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1559 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1560
1561 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1562
1563 <dd>Perform the <a href="#i_extractelement">extractelement
1564 operation</a> on constants.
1565
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1566 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1567
1568 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1569 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1570
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1571
1572 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1573
1574 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1575 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1576
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1577 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1578
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1579 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1580 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1581 binary</a> operations. The constraints on operands are the same as those for
1582 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1583 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1584</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1585</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1587<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1588<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1589<!-- *********************************************************************** -->
1590
1591<!-- ======================================================================= -->
1592<div class="doc_subsection">
1593<a name="inlineasm">Inline Assembler Expressions</a>
1594</div>
1595
1596<div class="doc_text">
1597
1598<p>
1599LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1600Module-Level Inline Assembly</a>) through the use of a special value. This
1601value represents the inline assembler as a string (containing the instructions
1602to emit), a list of operand constraints (stored as a string), and a flag that
1603indicates whether or not the inline asm expression has side effects. An example
1604inline assembler expression is:
1605</p>
1606
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1607<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1608<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1609i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1610</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1611</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1612
1613<p>
1614Inline assembler expressions may <b>only</b> be used as the callee operand of
1615a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1616</p>
1617
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1618<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1619<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1620%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]1621</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1622</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1623
1624<p>
1625Inline asms with side effects not visible in the constraint list must be marked
1626as having side effects. This is done through the use of the
1627'<tt>sideeffect</tt>' keyword, like so:
1628</p>
1629
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1630<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1631<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1632call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1633</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1634</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1635
1636<p>TODO: The format of the asm and constraints string still need to be
1637documented here. Constraints on what can be done (e.g. duplication, moving, etc
1638need to be documented).
1639</p>
1640
1641</div>
1642
1643<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1644<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1645<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1647<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1649<p>The LLVM instruction set consists of several different
1650classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1651instructions</a>, <a href="#binaryops">binary instructions</a>,
1652<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1653 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1654instructions</a>.</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_subsection"> <a name="terminators">Terminator
1660Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1662<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1663
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1664<p>As mentioned <a href="#functionstructure">previously</a>, every
1665basic block in a program ends with a "Terminator" instruction, which
1666indicates which block should be executed after the current block is
1667finished. These terminator instructions typically yield a '<tt>void</tt>'
1668value: they produce control flow, not values (the one exception being
1669the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1670<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1672instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1673the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1674 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1675 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1676
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1677</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1678
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1679<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1680<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1681Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1682<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1684<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]1685 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1686</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1688<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1689value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1690<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1691returns a value and then causes control flow, and one that just causes
1692control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1693<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1694<p>The '<tt>ret</tt>' instruction may return any '<a
1695 href="#t_firstclass">first class</a>' type. Notice that a function is
1696not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1697instruction inside of the function that returns a value that does not
1698match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<p>When the '<tt>ret</tt>' instruction is executed, control flow
1701returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1702 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1703the instruction after the call. If the caller was an "<a
1704 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1705at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706returns a value, that value shall set the call or invoke instruction's
1707return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1708<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1709<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1710 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1711</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1712</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1715<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1717<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]1718</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1719<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1720<p>The '<tt>br</tt>' instruction is used to cause control flow to
1721transfer to a different basic block in the current function. There are
1722two forms of this instruction, corresponding to a conditional branch
1723and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1726single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1727unconditional form of the '<tt>br</tt>' instruction takes a single
1728'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1730<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1731argument is evaluated. If the value is <tt>true</tt>, control flows
1732to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1733control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1735<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]1736 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]1737</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1739<div class="doc_subsubsection">
1740 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1741</div>
1742
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1744<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1745
1746<pre>
1747 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1748</pre>
1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1751
1752<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1753several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1754instruction, allowing a branch to occur to one of many possible
1755destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1756
1757
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1759
1760<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1761comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1762an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1763table is not allowed to contain duplicate constant entries.</p>
1764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1765<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1766
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1767<p>The <tt>switch</tt> instruction specifies a table of values and
1768destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1769table is searched for the given value. If the value is found, control flow is
1770transfered to the corresponding destination; otherwise, control flow is
1771transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1773<h5>Implementation:</h5>
1774
1775<p>Depending on properties of the target machine and the particular
1776<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1777ways. For example, it could be generated as a series of chained conditional
1778branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1779
1780<h5>Example:</h5>
1781
1782<pre>
1783 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1784 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1785 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1786
1787 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1788 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1789
1790 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1791 switch i32 %val, label %otherwise [ i32 0, label %onzero
1792 i32 1, label %onone
1793 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1795</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1797<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1798<div class="doc_subsubsection">
1799 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1800</div>
1801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1802<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1803
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1804<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1805
1806<pre>
1807 &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]1808 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1809</pre>
1810
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1811<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1812
1813<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1814function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1815'<tt>normal</tt>' label or the
1816'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1817"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1818"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1819href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1820continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1823
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1824<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1825
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1826<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1827 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1828 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1829 convention</a> the call should use. If none is specified, the call defaults
1830 to using C calling conventions.
1831 </li>
1832 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1833 function value being invoked. In most cases, this is a direct function
1834 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1835 an arbitrary pointer to function value.
1836 </li>
1837
1838 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1839 function to be invoked. </li>
1840
1841 <li>'<tt>function args</tt>': argument list whose types match the function
1842 signature argument types. If the function signature indicates the function
1843 accepts a variable number of arguments, the extra arguments can be
1844 specified. </li>
1845
1846 <li>'<tt>normal label</tt>': the label reached when the called function
1847 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1848
1849 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1850 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1851
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1852</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1854<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1857href="#i_call">call</a></tt>' instruction in most regards. The primary
1858difference is that it establishes an association with a label, which is used by
1859the runtime library to unwind the stack.</p>
1860
1861<p>This instruction is used in languages with destructors to ensure that proper
1862cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1863exception. Additionally, this is important for implementation of
1864'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1865
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1866<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1867<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1868 %retval = invoke i32 %Test(i32 15) to label %Continue
1869 unwind label %TestCleanup <i>; {i32}:retval set</i>
1870 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1871 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1872</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1873</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1874
1875
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1876<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1877
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1879Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1881<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1882
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1883<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1884<pre>
1885 unwind
1886</pre>
1887
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1888<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1889
1890<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1891at the first callee in the dynamic call stack which used an <a
1892href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1893primarily used to implement exception handling.</p>
1894
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1895<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1896
1897<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1898immediately halt. The dynamic call stack is then searched for the first <a
1899href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1900execution continues at the "exceptional" destination block specified by the
1901<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1902dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1903</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1904
1905<!-- _______________________________________________________________________ -->
1906
1907<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1908Instruction</a> </div>
1909
1910<div class="doc_text">
1911
1912<h5>Syntax:</h5>
1913<pre>
1914 unreachable
1915</pre>
1916
1917<h5>Overview:</h5>
1918
1919<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1920instruction is used to inform the optimizer that a particular portion of the
1921code is not reachable. This can be used to indicate that the code after a
1922no-return function cannot be reached, and other facts.</p>
1923
1924<h5>Semantics:</h5>
1925
1926<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1927</div>
1928
1929
1930
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1931<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1932<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1933<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1934<p>Binary operators are used to do most of the computation in a
1935program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1936produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1937multiple 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]1938The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1939necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<p>There are several different binary operators:</p>
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_add">'<tt>add</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; = 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]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>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1952<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1953 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1954 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]1955Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1956<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1957<p>The value produced is the integer or floating point sum of the two
1958operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1959<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1960<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]1961</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1962</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1963<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1964<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1965Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1966<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1967<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1968<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]1969</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1970<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1971<p>The '<tt>sub</tt>' instruction returns the difference of its two
1972operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1973<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1974instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1976<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1977 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1978values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1979This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1980Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1981<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1982<p>The value produced is the integer or floating point difference of
1983the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1984<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1985<pre>
1986 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1987 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1988</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1989</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1991<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1992Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1995<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]1996</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1998<p>The '<tt>mul</tt>' instruction returns the product of its two
1999operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2001<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2002 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2003values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2004This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2005Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2006<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2007<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2008two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2009<p>Because the operands are the same width, the result of an integer
2010multiplication is the same whether the operands should be deemed unsigned or
2011signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2012<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2013<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]2014</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2015</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2016<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2017<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2018</a></div>
2019<div class="doc_text">
2020<h5>Syntax:</h5>
2021<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2022</pre>
2023<h5>Overview:</h5>
2024<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2025operands.</p>
2026<h5>Arguments:</h5>
2027<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2028<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2029types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2030of the values in which case the elements must be integers.</p>
2031<h5>Semantics:</h5>
2032<p>The value produced is the unsigned integer quotient of the two operands. This
2033instruction always performs an unsigned division operation, regardless of
2034whether the arguments are unsigned or not.</p>
2035<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2036<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]2037</pre>
2038</div>
2039<!-- _______________________________________________________________________ -->
2040<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2041</a> </div>
2042<div class="doc_text">
2043<h5>Syntax:</h5>
2044<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2045</pre>
2046<h5>Overview:</h5>
2047<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2048operands.</p>
2049<h5>Arguments:</h5>
2050<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2051<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2052types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2053of the values in which case the elements must be integers.</p>
2054<h5>Semantics:</h5>
2055<p>The value produced is the signed integer quotient of the two operands. This
2056instruction always performs a signed division operation, regardless of whether
2057the arguments are signed or not.</p>
2058<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2059<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]2060</pre>
2061</div>
2062<!-- _______________________________________________________________________ -->
2063<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2064Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2065<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2066<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2067<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]2068</pre>
2069<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2070<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2071operands.</p>
2072<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2073<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2074<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2075identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2076versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2077<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2078<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2079<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2080<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]2081</pre>
2082</div>
2083<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2084<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2085</div>
2086<div class="doc_text">
2087<h5>Syntax:</h5>
2088<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2089</pre>
2090<h5>Overview:</h5>
2091<p>The '<tt>urem</tt>' instruction returns the remainder from the
2092unsigned division of its two arguments.</p>
2093<h5>Arguments:</h5>
2094<p>The two arguments to the '<tt>urem</tt>' instruction must be
2095<a href="#t_integer">integer</a> values. Both arguments must have identical
2096types.</p>
2097<h5>Semantics:</h5>
2098<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2099This instruction always performs an unsigned division to get the remainder,
2100regardless of whether the arguments are unsigned or not.</p>
2101<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2102<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]2103</pre>
2104
2105</div>
2106<!-- _______________________________________________________________________ -->
2107<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2108Instruction</a> </div>
2109<div class="doc_text">
2110<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2111<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]2112</pre>
2113<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2114<p>The '<tt>srem</tt>' instruction returns the remainder from the
2115signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2116<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2117<p>The two arguments to the '<tt>srem</tt>' instruction must be
2118<a href="#t_integer">integer</a> values. Both arguments must have identical
2119types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2120<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2121<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2122has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2123operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2124a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2125 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2126Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2127please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2128Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2129<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2130<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]2131</pre>
2132
2133</div>
2134<!-- _______________________________________________________________________ -->
2135<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2136Instruction</a> </div>
2137<div class="doc_text">
2138<h5>Syntax:</h5>
2139<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2140</pre>
2141<h5>Overview:</h5>
2142<p>The '<tt>frem</tt>' instruction returns the remainder from the
2143division of its two operands.</p>
2144<h5>Arguments:</h5>
2145<p>The two arguments to the '<tt>frem</tt>' instruction must be
2146<a href="#t_floating">floating point</a> values. Both arguments must have
2147identical types.</p>
2148<h5>Semantics:</h5>
2149<p>This instruction returns the <i>remainder</i> of a division.</p>
2150<h5>Example:</h5>
2151<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]2152</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2153</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2154
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2155<!-- ======================================================================= -->
2156<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2157Operations</a> </div>
2158<div class="doc_text">
2159<p>Bitwise binary operators are used to do various forms of
2160bit-twiddling in a program. They are generally very efficient
2161instructions and can commonly be strength reduced from other
2162instructions. They require two operands, execute an operation on them,
2163and produce a single value. The resulting value of the bitwise binary
2164operators is always the same type as its first operand.</p>
2165</div>
2166
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2167<!-- _______________________________________________________________________ -->
2168<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2169Instruction</a> </div>
2170<div class="doc_text">
2171<h5>Syntax:</h5>
2172<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2173</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2174
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2175<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2176
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2177<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2178the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2179
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2180<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2181
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2182<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2183 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2184
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2185<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2186
2187<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2188<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2189of bits in <tt>var1</tt>, the result is undefined.</p>
2190
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2191<h5>Example:</h5><pre>
2192 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2193 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2194 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2195 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2196</pre>
2197</div>
2198<!-- _______________________________________________________________________ -->
2199<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2200Instruction</a> </div>
2201<div class="doc_text">
2202<h5>Syntax:</h5>
2203<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2204</pre>
2205
2206<h5>Overview:</h5>
2207<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2208operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2209
2210<h5>Arguments:</h5>
2211<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2212<a href="#t_integer">integer</a> type.</p>
2213
2214<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2215
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2216<p>This instruction always performs a logical shift right operation. The most
2217significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2218shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2219the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2220
2221<h5>Example:</h5>
2222<pre>
2223 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2224 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2225 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2226 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2227 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2228</pre>
2229</div>
2230
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2231<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2232<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2233Instruction</a> </div>
2234<div class="doc_text">
2235
2236<h5>Syntax:</h5>
2237<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2238</pre>
2239
2240<h5>Overview:</h5>
2241<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2242operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2243
2244<h5>Arguments:</h5>
2245<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2246<a href="#t_integer">integer</a> type.</p>
2247
2248<h5>Semantics:</h5>
2249<p>This instruction always performs an arithmetic shift right operation,
2250The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2251of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2252larger than the number of bits in <tt>var1</tt>, the result is undefined.
2253</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2254
2255<h5>Example:</h5>
2256<pre>
2257 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2258 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2259 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2260 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2261 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2262</pre>
2263</div>
2264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2265<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2266<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2267Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2268<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2269<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2270<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]2271</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2272<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2273<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2274its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2275<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2276<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2277 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2278identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2279<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2280<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2281<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2282<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2283<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2284 <tbody>
2285 <tr>
2286 <td>In0</td>
2287 <td>In1</td>
2288 <td>Out</td>
2289 </tr>
2290 <tr>
2291 <td>0</td>
2292 <td>0</td>
2293 <td>0</td>
2294 </tr>
2295 <tr>
2296 <td>0</td>
2297 <td>1</td>
2298 <td>0</td>
2299 </tr>
2300 <tr>
2301 <td>1</td>
2302 <td>0</td>
2303 <td>0</td>
2304 </tr>
2305 <tr>
2306 <td>1</td>
2307 <td>1</td>
2308 <td>1</td>
2309 </tr>
2310 </tbody>
2311</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2312</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2313<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2314<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2315 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2316 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2317</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2318</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2319<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2320<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2321<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2322<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2323<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]2324</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2325<h5>Overview:</h5>
2326<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2327or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2328<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2329<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2330 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2331identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2332<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2333<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2334<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2335<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2336<table border="1" cellspacing="0" cellpadding="4">
2337 <tbody>
2338 <tr>
2339 <td>In0</td>
2340 <td>In1</td>
2341 <td>Out</td>
2342 </tr>
2343 <tr>
2344 <td>0</td>
2345 <td>0</td>
2346 <td>0</td>
2347 </tr>
2348 <tr>
2349 <td>0</td>
2350 <td>1</td>
2351 <td>1</td>
2352 </tr>
2353 <tr>
2354 <td>1</td>
2355 <td>0</td>
2356 <td>1</td>
2357 </tr>
2358 <tr>
2359 <td>1</td>
2360 <td>1</td>
2361 <td>1</td>
2362 </tr>
2363 </tbody>
2364</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2365</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2366<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2367<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2368 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2369 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2370</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2371</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2372<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2373<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2374Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2375<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2376<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2377<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]2378</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2379<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2380<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2381or of its two operands. The <tt>xor</tt> is used to implement the
2382"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2383<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2384<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2385 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2386identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2387<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2388<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2389<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2390<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2391<table border="1" cellspacing="0" cellpadding="4">
2392 <tbody>
2393 <tr>
2394 <td>In0</td>
2395 <td>In1</td>
2396 <td>Out</td>
2397 </tr>
2398 <tr>
2399 <td>0</td>
2400 <td>0</td>
2401 <td>0</td>
2402 </tr>
2403 <tr>
2404 <td>0</td>
2405 <td>1</td>
2406 <td>1</td>
2407 </tr>
2408 <tr>
2409 <td>1</td>
2410 <td>0</td>
2411 <td>1</td>
2412 </tr>
2413 <tr>
2414 <td>1</td>
2415 <td>1</td>
2416 <td>0</td>
2417 </tr>
2418 </tbody>
2419</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2420</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2421<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2423<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2424 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2425 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2426 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2427</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2428</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2429
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2430<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2431<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2432 <a name="vectorops">Vector Operations</a>
2433</div>
2434
2435<div class="doc_text">
2436
2437<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2438target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2439vector-specific operations needed to process vectors effectively. While LLVM
2440does directly support these vector operations, many sophisticated algorithms
2441will want to use target-specific intrinsics to take full advantage of a specific
2442target.</p>
2443
2444</div>
2445
2446<!-- _______________________________________________________________________ -->
2447<div class="doc_subsubsection">
2448 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2449</div>
2450
2451<div class="doc_text">
2452
2453<h5>Syntax:</h5>
2454
2455<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2456 &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]2457</pre>
2458
2459<h5>Overview:</h5>
2460
2461<p>
2462The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2463element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2464</p>
2465
2466
2467<h5>Arguments:</h5>
2468
2469<p>
2470The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2471value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2472an index indicating the position from which to extract the element.
2473The index may be a variable.</p>
2474
2475<h5>Semantics:</h5>
2476
2477<p>
2478The result is a scalar of the same type as the element type of
2479<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2480<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2481results are undefined.
2482</p>
2483
2484<h5>Example:</h5>
2485
2486<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2487 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2488</pre>
2489</div>
2490
2491
2492<!-- _______________________________________________________________________ -->
2493<div class="doc_subsubsection">
2494 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2495</div>
2496
2497<div class="doc_text">
2498
2499<h5>Syntax:</h5>
2500
2501<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2502 &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]2503</pre>
2504
2505<h5>Overview:</h5>
2506
2507<p>
2508The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2509element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2510</p>
2511
2512
2513<h5>Arguments:</h5>
2514
2515<p>
2516The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2517value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2518scalar value whose type must equal the element type of the first
2519operand. The third operand is an index indicating the position at
2520which to insert the value. The index may be a variable.</p>
2521
2522<h5>Semantics:</h5>
2523
2524<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2525The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2526element values are those of <tt>val</tt> except at position
2527<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2528exceeds the length of <tt>val</tt>, the results are undefined.
2529</p>
2530
2531<h5>Example:</h5>
2532
2533<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2534 %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]2535</pre>
2536</div>
2537
2538<!-- _______________________________________________________________________ -->
2539<div class="doc_subsubsection">
2540 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2541</div>
2542
2543<div class="doc_text">
2544
2545<h5>Syntax:</h5>
2546
2547<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2548 &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]2549</pre>
2550
2551<h5>Overview:</h5>
2552
2553<p>
2554The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2555from two input vectors, returning a vector of the same type.
2556</p>
2557
2558<h5>Arguments:</h5>
2559
2560<p>
2561The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2562with types that match each other and types that match the result of the
2563instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2564of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2565</p>
2566
2567<p>
2568The shuffle mask operand is required to be a constant vector with either
2569constant integer or undef values.
2570</p>
2571
2572<h5>Semantics:</h5>
2573
2574<p>
2575The elements of the two input vectors are numbered from left to right across
2576both of the vectors. The shuffle mask operand specifies, for each element of
2577the result vector, which element of the two input registers the result element
2578gets. The element selector may be undef (meaning "don't care") and the second
2579operand may be undef if performing a shuffle from only one vector.
2580</p>
2581
2582<h5>Example:</h5>
2583
2584<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2585 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2586 &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]2587 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2588 &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]2589</pre>
2590</div>
2591
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2592
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2593<!-- ======================================================================= -->
2594<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2595 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2596</div>
2597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2598<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2599
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2600<p>A key design point of an SSA-based representation is how it
2601represents memory. In LLVM, no memory locations are in SSA form, which
2602makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2603allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2605</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2606
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2607<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2608<div class="doc_subsubsection">
2609 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2610</div>
2611
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2612<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2614<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2615
2616<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2617 &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]2618</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2619
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2620<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2621
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2622<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2623heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2625<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2626
2627<p>The '<tt>malloc</tt>' instruction allocates
2628<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2629bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2630appropriate type to the program. If "NumElements" is specified, it is the
2631number of elements allocated. If an alignment is specified, the value result
2632of the allocation is guaranteed to be aligned to at least that boundary. If
2633not specified, or if zero, the target can choose to align the allocation on any
2634convenient boundary.</p>
2635
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2636<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2638<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2639
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2640<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2641a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2642
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2643<h5>Example:</h5>
2644
2645<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2646 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2647
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2648 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2649 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2650 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2651 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2652 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2653</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2654</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2656<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2657<div class="doc_subsubsection">
2658 <a name="i_free">'<tt>free</tt>' Instruction</a>
2659</div>
2660
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2661<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2662
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2663<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2664
2665<pre>
2666 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2667</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2669<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2670
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2671<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2672memory heap to be reallocated in the future.</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
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2676<p>'<tt>value</tt>' shall be a pointer value that points to a value
2677that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2678instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2679
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2680<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2681
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2682<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2683after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2685<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2686
2687<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2688 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2689 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2690</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2691</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2692
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2693<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2694<div class="doc_subsubsection">
2695 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2696</div>
2697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2698<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2700<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2701
2702<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2703 &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]2704</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2706<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2707
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2708<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2709currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2710returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2711
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2712<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2713
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2714<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2715bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2716appropriate type to the program. If "NumElements" is specified, it is the
2717number of elements allocated. If an alignment is specified, the value result
2718of the allocation is guaranteed to be aligned to at least that boundary. If
2719not specified, or if zero, the target can choose to align the allocation on any
2720convenient boundary.</p>
2721
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2722<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2723
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2724<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2725
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2726<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2727memory is automatically released when the function returns. The '<tt>alloca</tt>'
2728instruction is commonly used to represent automatic variables that must
2729have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2730 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]2731instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2733<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2734
2735<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2736 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2737 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2738 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2739 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2740</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2741</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2742
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2743<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2744<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2745Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2746<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2747<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2748<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]2749<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2750<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2751<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2752<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2753address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2754 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2755marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2756the number or order of execution of this <tt>load</tt> with other
2757volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2758instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2759<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2760<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2761<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2762<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2763 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2764 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2765 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2766</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2767</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2768<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2769<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2770Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2771<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2772<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2773<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2774 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]2775</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2776<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2777<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2778<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2779<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2780to 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]2781operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2782operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2783optimizer is not allowed to modify the number or order of execution of
2784this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2785 href="#i_store">store</a></tt> instructions.</p>
2786<h5>Semantics:</h5>
2787<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2788at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2789<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2790<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame^]2791 store i32 3, i32* %ptr <i>; yields {void}</i>
2792 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2793</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2794</div>
2795
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2796<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2797<div class="doc_subsubsection">
2798 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2799</div>
2800
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2801<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2802<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2803<pre>
2804 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2805</pre>
2806
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2807<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2808
2809<p>
2810The '<tt>getelementptr</tt>' instruction is used to get the address of a
2811subelement of an aggregate data structure.</p>
2812
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2813<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2814
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2815<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2816elements of the aggregate object to index to. The actual types of the arguments
2817provided depend on the type of the first pointer argument. The
2818'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2819levels 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]2820structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2821into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2822be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2823
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2824<p>For example, let's consider a C code fragment and how it gets
2825compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2826
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2827<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2828<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2829struct RT {
2830 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2831 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2832 char C;
2833};
2834struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2835 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2836 double Y;
2837 struct RT Z;
2838};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2839
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2840int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2841 return &amp;s[1].Z.B[5][13];
2842}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2843</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2844</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2846<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2847
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2848<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2849<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2850%RT = type { i8 , [10 x [20 x i32]], i8 }
2851%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2852
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2853define i32* %foo(%ST* %s) {
2854entry:
2855 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2856 ret i32* %reg
2857}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2858</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2859</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2860
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2861<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2862
2863<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2864on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2865and <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]2866<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]2867to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2868<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2869
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2870<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]2871type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2872}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2873the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2874i8 }</tt>' type, another structure. The third index indexes into the second
2875element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2876array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2877'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2878to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2879
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2880<p>Note that it is perfectly legal to index partially through a
2881structure, returning a pointer to an inner element. Because of this,
2882the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2883
2884<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2885 define i32* %foo(%ST* %s) {
2886 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2887 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2888 %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]2889 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2890 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2891 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2892 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2893</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2894
2895<p>Note that it is undefined to access an array out of bounds: array and
2896pointer indexes must always be within the defined bounds of the array type.
2897The one exception for this rules is zero length arrays. These arrays are
2898defined to be accessible as variable length arrays, which requires access
2899beyond the zero'th element.</p>
2900
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2901<p>The getelementptr instruction is often confusing. For some more insight
2902into how it works, see <a href="GetElementPtr.html">the getelementptr
2903FAQ</a>.</p>
2904
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2905<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2906
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2907<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2908 <i>; yields [12 x i8]*:aptr</i>
2909 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2910</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2911</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2913<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2914<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2915</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2916<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2917<p>The instructions in this category are the conversion instructions (casting)
2918which all take a single operand and a type. They perform various bit conversions
2919on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2920</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2921
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2922<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2923<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2924 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2925</div>
2926<div class="doc_text">
2927
2928<h5>Syntax:</h5>
2929<pre>
2930 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2931</pre>
2932
2933<h5>Overview:</h5>
2934<p>
2935The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2936</p>
2937
2938<h5>Arguments:</h5>
2939<p>
2940The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2941be 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]2942and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2943type. The bit size of <tt>value</tt> must be larger than the bit size of
2944<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2945
2946<h5>Semantics:</h5>
2947<p>
2948The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2949and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2950larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2951It will always truncate bits.</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 = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2956 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2957 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2958</pre>
2959</div>
2960
2961<!-- _______________________________________________________________________ -->
2962<div class="doc_subsubsection">
2963 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2964</div>
2965<div class="doc_text">
2966
2967<h5>Syntax:</h5>
2968<pre>
2969 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2970</pre>
2971
2972<h5>Overview:</h5>
2973<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2974<tt>ty2</tt>.</p>
2975
2976
2977<h5>Arguments:</h5>
2978<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]2979<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2980also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2981<tt>value</tt> must be smaller than the bit size of the destination type,
2982<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2983
2984<h5>Semantics:</h5>
2985<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]2986bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2987
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2988<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]2989
2990<h5>Example:</h5>
2991<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2992 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2993 %Y = zext 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">
2999 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3000</div>
3001<div class="doc_text">
3002
3003<h5>Syntax:</h5>
3004<pre>
3005 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3006</pre>
3007
3008<h5>Overview:</h5>
3009<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3010
3011<h5>Arguments:</h5>
3012<p>
3013The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3014<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3015also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3016<tt>value</tt> must be smaller than the bit size of the destination type,
3017<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3018
3019<h5>Semantics:</h5>
3020<p>
3021The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3022bit (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]3023the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3024
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3025<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]3026
3027<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3028<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3029 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3030 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3031</pre>
3032</div>
3033
3034<!-- _______________________________________________________________________ -->
3035<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3036 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3037</div>
3038
3039<div class="doc_text">
3040
3041<h5>Syntax:</h5>
3042
3043<pre>
3044 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3045</pre>
3046
3047<h5>Overview:</h5>
3048<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3049<tt>ty2</tt>.</p>
3050
3051
3052<h5>Arguments:</h5>
3053<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3054 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3055cast it to. The size of <tt>value</tt> must be larger than the size of
3056<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3057<i>no-op cast</i>.</p>
3058
3059<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3060<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3061<a href="#t_floating">floating point</a> type to a smaller
3062<a href="#t_floating">floating point</a> type. If the value cannot fit within
3063the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3064
3065<h5>Example:</h5>
3066<pre>
3067 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3068 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3069</pre>
3070</div>
3071
3072<!-- _______________________________________________________________________ -->
3073<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3074 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3075</div>
3076<div class="doc_text">
3077
3078<h5>Syntax:</h5>
3079<pre>
3080 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3081</pre>
3082
3083<h5>Overview:</h5>
3084<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3085floating point value.</p>
3086
3087<h5>Arguments:</h5>
3088<p>The '<tt>fpext</tt>' instruction takes a
3089<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3090and a <a href="#t_floating">floating point</a> type to cast it to. The source
3091type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3092
3093<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3094<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3095<a href="#t_floating">floating point</a> type to a larger
3096<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3097used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3098<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]3099
3100<h5>Example:</h5>
3101<pre>
3102 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3103 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3104</pre>
3105</div>
3106
3107<!-- _______________________________________________________________________ -->
3108<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3109 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3110</div>
3111<div class="doc_text">
3112
3113<h5>Syntax:</h5>
3114<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3115 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3116</pre>
3117
3118<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3119<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3120unsigned integer equivalent of type <tt>ty2</tt>.
3121</p>
3122
3123<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3124<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3125<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]3126must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3127
3128<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3129<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3130<a href="#t_floating">floating point</a> operand into the nearest (rounding
3131towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3132the results are undefined.</p>
3133
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3134<h5>Example:</h5>
3135<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3136 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3137 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3138 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3139</pre>
3140</div>
3141
3142<!-- _______________________________________________________________________ -->
3143<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3144 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3145</div>
3146<div class="doc_text">
3147
3148<h5>Syntax:</h5>
3149<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3150 &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]3151</pre>
3152
3153<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3154<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3155<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]3156</p>
3157
3158
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3159<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3160<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]3161<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]3162must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3163
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3164<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3165<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3166<a href="#t_floating">floating point</a> operand into the nearest (rounding
3167towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3168the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3169
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3170<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3171<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3172 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3173 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3174 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3175</pre>
3176</div>
3177
3178<!-- _______________________________________________________________________ -->
3179<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3180 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3181</div>
3182<div class="doc_text">
3183
3184<h5>Syntax:</h5>
3185<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3186 &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]3187</pre>
3188
3189<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3190<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3191integer and converts that value to the <tt>ty2</tt> type.</p>
3192
3193
3194<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3195<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]3196<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]3197be a <a href="#t_floating">floating point</a> type.</p>
3198
3199<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3200<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3201integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3202the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3203
3204
3205<h5>Example:</h5>
3206<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3207 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3208 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3209</pre>
3210</div>
3211
3212<!-- _______________________________________________________________________ -->
3213<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3214 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3215</div>
3216<div class="doc_text">
3217
3218<h5>Syntax:</h5>
3219<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3220 &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]3221</pre>
3222
3223<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3224<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3225integer and converts that value to the <tt>ty2</tt> type.</p>
3226
3227<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3228<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]3229<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]3230a <a href="#t_floating">floating point</a> type.</p>
3231
3232<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3233<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3234integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3235the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3236
3237<h5>Example:</h5>
3238<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3239 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3240 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3241</pre>
3242</div>
3243
3244<!-- _______________________________________________________________________ -->
3245<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3246 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3247</div>
3248<div class="doc_text">
3249
3250<h5>Syntax:</h5>
3251<pre>
3252 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3253</pre>
3254
3255<h5>Overview:</h5>
3256<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3257the integer type <tt>ty2</tt>.</p>
3258
3259<h5>Arguments:</h5>
3260<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3261must 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]3262<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3263
3264<h5>Semantics:</h5>
3265<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3266<tt>ty2</tt> by interpreting the pointer value as an integer and either
3267truncating or zero extending that value to the size of the integer type. If
3268<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3269<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]3270are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3271change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3272
3273<h5>Example:</h5>
3274<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3275 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3276 %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]3277</pre>
3278</div>
3279
3280<!-- _______________________________________________________________________ -->
3281<div class="doc_subsubsection">
3282 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3283</div>
3284<div class="doc_text">
3285
3286<h5>Syntax:</h5>
3287<pre>
3288 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3289</pre>
3290
3291<h5>Overview:</h5>
3292<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3293a pointer type, <tt>ty2</tt>.</p>
3294
3295<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3296<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3297value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3298<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3299
3300<h5>Semantics:</h5>
3301<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3302<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3303the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3304size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3305the size of a pointer then a zero extension is done. If they are the same size,
3306nothing is done (<i>no-op cast</i>).</p>
3307
3308<h5>Example:</h5>
3309<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3310 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3311 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3312 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3313</pre>
3314</div>
3315
3316<!-- _______________________________________________________________________ -->
3317<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3318 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3319</div>
3320<div class="doc_text">
3321
3322<h5>Syntax:</h5>
3323<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3324 &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]3325</pre>
3326
3327<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3328<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3329<tt>ty2</tt> without changing any bits.</p>
3330
3331<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3332<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3333a first class value, and a type to cast it to, which must also be a <a
3334 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3335and the destination type, <tt>ty2</tt>, must be identical. If the source
3336type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3337
3338<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3339<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3340<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3341this conversion. The conversion is done as if the <tt>value</tt> had been
3342stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3343converted to other pointer types with this instruction. To convert pointers to
3344other types, use the <a href="#i_inttoptr">inttoptr</a> or
3345<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3346
3347<h5>Example:</h5>
3348<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3349 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3350 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3351 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3352</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3353</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3354
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3355<!-- ======================================================================= -->
3356<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3357<div class="doc_text">
3358<p>The instructions in this category are the "miscellaneous"
3359instructions, which defy better classification.</p>
3360</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3361
3362<!-- _______________________________________________________________________ -->
3363<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3364</div>
3365<div class="doc_text">
3366<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3367<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]3368</pre>
3369<h5>Overview:</h5>
3370<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3371of its two integer operands.</p>
3372<h5>Arguments:</h5>
3373<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3374the condition code indicating the kind of comparison to perform. It is not
3375a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3376<ol>
3377 <li><tt>eq</tt>: equal</li>
3378 <li><tt>ne</tt>: not equal </li>
3379 <li><tt>ugt</tt>: unsigned greater than</li>
3380 <li><tt>uge</tt>: unsigned greater or equal</li>
3381 <li><tt>ult</tt>: unsigned less than</li>
3382 <li><tt>ule</tt>: unsigned less or equal</li>
3383 <li><tt>sgt</tt>: signed greater than</li>
3384 <li><tt>sge</tt>: signed greater or equal</li>
3385 <li><tt>slt</tt>: signed less than</li>
3386 <li><tt>sle</tt>: signed less or equal</li>
3387</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3388<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3389<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3390<h5>Semantics:</h5>
3391<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3392the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3393yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3394<ol>
3395 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3396 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3397 </li>
3398 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3399 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3400 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3401 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3402 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3403 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3404 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3405 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3406 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3407 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3408 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3409 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3410 <li><tt>sge</tt>: interprets the operands as signed values and yields
3411 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3412 <li><tt>slt</tt>: interprets the operands as signed values and yields
3413 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3414 <li><tt>sle</tt>: interprets the operands as signed values and yields
3415 <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]3416</ol>
3417<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3418values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3419
3420<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3421<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3422 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3423 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3424 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3425 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3426 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3427</pre>
3428</div>
3429
3430<!-- _______________________________________________________________________ -->
3431<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3432</div>
3433<div class="doc_text">
3434<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3435<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]3436</pre>
3437<h5>Overview:</h5>
3438<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3439of its floating point operands.</p>
3440<h5>Arguments:</h5>
3441<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3442the condition code indicating the kind of comparison to perform. It is not
3443a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3444<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3445 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3446 <li><tt>oeq</tt>: ordered and equal</li>
3447 <li><tt>ogt</tt>: ordered and greater than </li>
3448 <li><tt>oge</tt>: ordered and greater than or equal</li>
3449 <li><tt>olt</tt>: ordered and less than </li>
3450 <li><tt>ole</tt>: ordered and less than or equal</li>
3451 <li><tt>one</tt>: ordered and not equal</li>
3452 <li><tt>ord</tt>: ordered (no nans)</li>
3453 <li><tt>ueq</tt>: unordered or equal</li>
3454 <li><tt>ugt</tt>: unordered or greater than </li>
3455 <li><tt>uge</tt>: unordered or greater than or equal</li>
3456 <li><tt>ult</tt>: unordered or less than </li>
3457 <li><tt>ule</tt>: unordered or less than or equal</li>
3458 <li><tt>une</tt>: unordered or not equal</li>
3459 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3460 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3461</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3462<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3463<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3464<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3465<a href="#t_floating">floating point</a> typed. They must have identical
3466types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3467<h5>Semantics:</h5>
3468<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3469the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3470yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3471<ol>
3472 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3473 <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]3474 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3475 <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]3476 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3477 <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]3478 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3479 <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]3480 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3481 <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]3482 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3483 <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]3484 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3485 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3486 <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]3487 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3488 <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]3489 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3490 <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]3491 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3492 <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]3493 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3494 <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]3495 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3496 <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]3497 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3498 <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]3499 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3500</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3501
3502<h5>Example:</h5>
3503<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3504 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3505 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3506 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3507</pre>
3508</div>
3509
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3510<!-- _______________________________________________________________________ -->
3511<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3512Instruction</a> </div>
3513<div class="doc_text">
3514<h5>Syntax:</h5>
3515<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3516<h5>Overview:</h5>
3517<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3518the SSA graph representing the function.</p>
3519<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3520<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3521field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3522as arguments, with one pair for each predecessor basic block of the
3523current block. Only values of <a href="#t_firstclass">first class</a>
3524type may be used as the value arguments to the PHI node. Only labels
3525may be used as the label arguments.</p>
3526<p>There must be no non-phi instructions between the start of a basic
3527block and the PHI instructions: i.e. PHI instructions must be first in
3528a basic block.</p>
3529<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3530<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3531specified by the pair corresponding to the predecessor basic block that executed
3532just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3533<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3534<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]3535</div>
3536
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3537<!-- _______________________________________________________________________ -->
3538<div class="doc_subsubsection">
3539 <a name="i_select">'<tt>select</tt>' Instruction</a>
3540</div>
3541
3542<div class="doc_text">
3543
3544<h5>Syntax:</h5>
3545
3546<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3547 &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]3548</pre>
3549
3550<h5>Overview:</h5>
3551
3552<p>
3553The '<tt>select</tt>' instruction is used to choose one value based on a
3554condition, without branching.
3555</p>
3556
3557
3558<h5>Arguments:</h5>
3559
3560<p>
3561The '<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.
3562</p>
3563
3564<h5>Semantics:</h5>
3565
3566<p>
3567If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3568value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3569</p>
3570
3571<h5>Example:</h5>
3572
3573<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3574 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3575</pre>
3576</div>
3577
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3578
3579<!-- _______________________________________________________________________ -->
3580<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3581 <a name="i_call">'<tt>call</tt>' Instruction</a>
3582</div>
3583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3584<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3586<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3587<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3588 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3589</pre>
3590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3591<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3593<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3595<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3596
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3597<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3598
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3599<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3600 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3601 <p>The optional "tail" marker indicates whether the callee function accesses
3602 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3603 function call is eligible for tail call optimization. Note that calls may
3604 be marked "tail" even if they do not occur before a <a
3605 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3606 </li>
3607 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3608 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3609 convention</a> the call should use. If none is specified, the call defaults
3610 to using C calling conventions.
3611 </li>
3612 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3613 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3614 the type of the return value. Functions that return no value are marked
3615 <tt><a href="#t_void">void</a></tt>.</p>
3616 </li>
3617 <li>
3618 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3619 value being invoked. The argument types must match the types implied by
3620 this signature. This type can be omitted if the function is not varargs
3621 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3622 </li>
3623 <li>
3624 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3625 be invoked. In most cases, this is a direct function invocation, but
3626 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3627 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3628 </li>
3629 <li>
3630 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3631 function signature argument types. All arguments must be of
3632 <a href="#t_firstclass">first class</a> type. If the function signature
3633 indicates the function accepts a variable number of arguments, the extra
3634 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3635 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3636</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3638<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3639
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3640<p>The '<tt>call</tt>' instruction is used to cause control flow to
3641transfer to a specified function, with its incoming arguments bound to
3642the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3643instruction in the called function, control flow continues with the
3644instruction after the function call, and the return value of the
3645function is bound to the result argument. This is a simpler case of
3646the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3647
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3648<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3649
3650<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3651 %retval = call i32 @test(i32 %argc)
3652 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3653 %X = tail call i32 @foo()
3654 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3655 %Z = call void %foo(i8 97 signext)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3656</pre>
3657
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3658</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3659
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3660<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3661<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3662 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3663</div>
3664
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3665<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3666
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3667<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3668
3669<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3670 &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]3671</pre>
3672
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3673<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3674
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3675<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3676the "variable argument" area of a function call. It is used to implement the
3677<tt>va_arg</tt> macro in C.</p>
3678
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3679<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3680
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3681<p>This instruction takes a <tt>va_list*</tt> value and the type of
3682the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3683increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3684actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3685
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3686<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3687
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3688<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3689type from the specified <tt>va_list</tt> and causes the
3690<tt>va_list</tt> to point to the next argument. For more information,
3691see the variable argument handling <a href="#int_varargs">Intrinsic
3692Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3693
3694<p>It is legal for this instruction to be called in a function which does not
3695take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3696function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3697
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3698<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3699href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3700argument.</p>
3701
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3702<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3703
3704<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3705
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3706</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3707
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3708<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3709<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3710<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3712<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3713
3714<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3715well known names and semantics and are required to follow certain restrictions.
3716Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3717language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3718adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3719
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3720<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3721prefix is reserved in LLVM for intrinsic names; thus, function names may not
3722begin with this prefix. Intrinsic functions must always be external functions:
3723you cannot define the body of intrinsic functions. Intrinsic functions may
3724only be used in call or invoke instructions: it is illegal to take the address
3725of an intrinsic function. Additionally, because intrinsic functions are part
3726of the LLVM language, it is required if any are added that they be documented
3727here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3728
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3729<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3730a family of functions that perform the same operation but on different data
3731types. Because LLVM can represent over 8 million different integer types,
3732overloading is used commonly to allow an intrinsic function to operate on any
3733integer type. One or more of the argument types or the result type can be
3734overloaded to accept any integer type. Argument types may also be defined as
3735exactly matching a previous argument's type or the result type. This allows an
3736intrinsic function which accepts multiple arguments, but needs all of them to
3737be of the same type, to only be overloaded with respect to a single argument or
3738the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3739
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3740<p>Overloaded intrinsics will have the names of its overloaded argument types
3741encoded into its function name, each preceded by a period. Only those types
3742which are overloaded result in a name suffix. Arguments whose type is matched
3743against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3744take an integer of any width and returns an integer of exactly the same integer
3745width. This leads to a family of functions such as
3746<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3747Only one type, the return type, is overloaded, and only one type suffix is
3748required. Because the argument's type is matched against the return type, it
3749does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3750
3751<p>To learn how to add an intrinsic function, please see the
3752<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3753</p>
3754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3755</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3756
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3757<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3758<div class="doc_subsection">
3759 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3760</div>
3761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3762<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3763
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3764<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3765 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3766intrinsic functions. These functions are related to the similarly
3767named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3768
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3769<p>All of these functions operate on arguments that use a
3770target-specific value type "<tt>va_list</tt>". The LLVM assembly
3771language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3772transformations should be prepared to handle these functions regardless of
3773the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3774
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3775<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]3776instruction and the variable argument handling intrinsic functions are
3777used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3778
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3779<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3780<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3781define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3782 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3783 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3784 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3785 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3786
3787 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3788 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3789
3790 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3791 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3792 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3793 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3794 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3795
3796 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3797 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3798 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3799}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3800
3801declare void @llvm.va_start(i8*)
3802declare void @llvm.va_copy(i8*, i8*)
3803declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3804</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3805</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3806
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3807</div>
3808
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3809<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3810<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3811 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3812</div>
3813
3814
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3815<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3816<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3817<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3818<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3819<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3820<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3821href="#i_va_arg">va_arg</a></tt>.</p>
3822
3823<h5>Arguments:</h5>
3824
3825<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3826
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3827<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3828
3829<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3830macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3831<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]3832<tt>va_arg</tt> will produce the first variable argument passed to the function.
3833Unlike 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]3834last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3835
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3836</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3837
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3838<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3839<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3840 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3841</div>
3842
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3843<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3844<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3845<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3846<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3847
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3848<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3849which 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]3850or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3851
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3852<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3853
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3854<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]3855
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3856<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3857
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3858<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]3859macro available in C. In a target-dependent way, it destroys the
3860<tt>va_list</tt> element to which the argument points. Calls to <a
3861href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3862<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3863<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3864
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3865</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3866
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3867<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3868<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3869 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3870</div>
3871
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3872<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3873
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3874<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3875
3876<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3877 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3878</pre>
3879
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3880<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3881
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3882<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3883from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3884
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3885<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3886
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3887<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]3888The 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]3889
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3890
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3891<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3892
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3893<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3894macro available in C. In a target-dependent way, it copies the source
3895<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3896intrinsic is necessary because the <tt><a href="#int_va_start">
3897llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3898example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3899
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3900</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3901
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3902<!-- ======================================================================= -->
3903<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3904 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3905</div>
3906
3907<div class="doc_text">
3908
3909<p>
3910LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3911Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3912These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3913stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3914href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3915Front-ends for type-safe garbage collected languages should generate these
3916intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3917href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3918</p>
3919</div>
3920
3921<!-- _______________________________________________________________________ -->
3922<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3923 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3924</div>
3925
3926<div class="doc_text">
3927
3928<h5>Syntax:</h5>
3929
3930<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3931 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3932</pre>
3933
3934<h5>Overview:</h5>
3935
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3936<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]3937the code generator, and allows some metadata to be associated with it.</p>
3938
3939<h5>Arguments:</h5>
3940
3941<p>The first argument specifies the address of a stack object that contains the
3942root pointer. The second pointer (which must be either a constant or a global
3943value address) contains the meta-data to be associated with the root.</p>
3944
3945<h5>Semantics:</h5>
3946
3947<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3948location. At compile-time, the code generator generates information to allow
3949the runtime to find the pointer at GC safe points.
3950</p>
3951
3952</div>
3953
3954
3955<!-- _______________________________________________________________________ -->
3956<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3957 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3958</div>
3959
3960<div class="doc_text">
3961
3962<h5>Syntax:</h5>
3963
3964<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]3965 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3966</pre>
3967
3968<h5>Overview:</h5>
3969
3970<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3971locations, allowing garbage collector implementations that require read
3972barriers.</p>
3973
3974<h5>Arguments:</h5>
3975
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3976<p>The second argument is the address to read from, which should be an address
3977allocated from the garbage collector. The first object is a pointer to the
3978start of the referenced object, if needed by the language runtime (otherwise
3979null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3980
3981<h5>Semantics:</h5>
3982
3983<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3984instruction, but may be replaced with substantially more complex code by the
3985garbage collector runtime, as needed.</p>
3986
3987</div>
3988
3989
3990<!-- _______________________________________________________________________ -->
3991<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3992 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3993</div>
3994
3995<div class="doc_text">
3996
3997<h5>Syntax:</h5>
3998
3999<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4000 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4001</pre>
4002
4003<h5>Overview:</h5>
4004
4005<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4006locations, allowing garbage collector implementations that require write
4007barriers (such as generational or reference counting collectors).</p>
4008
4009<h5>Arguments:</h5>
4010
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4011<p>The first argument is the reference to store, the second is the start of the
4012object to store it to, and the third is the address of the field of Obj to
4013store to. If the runtime does not require a pointer to the object, Obj may be
4014null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4015
4016<h5>Semantics:</h5>
4017
4018<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4019instruction, but may be replaced with substantially more complex code by the
4020garbage collector runtime, as needed.</p>
4021
4022</div>
4023
4024
4025
4026<!-- ======================================================================= -->
4027<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4028 <a name="int_codegen">Code Generator Intrinsics</a>
4029</div>
4030
4031<div class="doc_text">
4032<p>
4033These intrinsics are provided by LLVM to expose special features that may only
4034be implemented with code generator support.
4035</p>
4036
4037</div>
4038
4039<!-- _______________________________________________________________________ -->
4040<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4041 <a name="int_returnaddress">'<tt>llvm.returnaddress</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.returnaddress(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.returnaddress</tt>' intrinsic attempts to compute a
4055target-specific value indicating the return address of the current function
4056or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4057</p>
4058
4059<h5>Arguments:</h5>
4060
4061<p>
4062The argument to this intrinsic indicates which function to return the address
4063for. Zero indicates the calling function, one indicates its caller, etc. The
4064argument is <b>required</b> to be a constant integer value.
4065</p>
4066
4067<h5>Semantics:</h5>
4068
4069<p>
4070The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4071the return address of the specified call frame, or zero if it cannot be
4072identified. The value returned by this intrinsic is likely to be incorrect or 0
4073for arguments other than zero, so it should only be used for debugging purposes.
4074</p>
4075
4076<p>
4077Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4078aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4079source-language caller.
4080</p>
4081</div>
4082
4083
4084<!-- _______________________________________________________________________ -->
4085<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4086 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4087</div>
4088
4089<div class="doc_text">
4090
4091<h5>Syntax:</h5>
4092<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4093 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4094</pre>
4095
4096<h5>Overview:</h5>
4097
4098<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4099The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4100target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4101</p>
4102
4103<h5>Arguments:</h5>
4104
4105<p>
4106The argument to this intrinsic indicates which function to return the frame
4107pointer for. Zero indicates the calling function, one indicates its caller,
4108etc. The argument is <b>required</b> to be a constant integer value.
4109</p>
4110
4111<h5>Semantics:</h5>
4112
4113<p>
4114The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4115the frame address of the specified call frame, or zero if it cannot be
4116identified. The value returned by this intrinsic is likely to be incorrect or 0
4117for arguments other than zero, so it should only be used for debugging purposes.
4118</p>
4119
4120<p>
4121Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4122aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4123source-language caller.
4124</p>
4125</div>
4126
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4127<!-- _______________________________________________________________________ -->
4128<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4129 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4130</div>
4131
4132<div class="doc_text">
4133
4134<h5>Syntax:</h5>
4135<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4136 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4137</pre>
4138
4139<h5>Overview:</h5>
4140
4141<p>
4142The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4143the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4144<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4145features like scoped automatic variable sized arrays in C99.
4146</p>
4147
4148<h5>Semantics:</h5>
4149
4150<p>
4151This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4152href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4153<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4154<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4155state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4156practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4157that were allocated after the <tt>llvm.stacksave</tt> was executed.
4158</p>
4159
4160</div>
4161
4162<!-- _______________________________________________________________________ -->
4163<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4164 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4165</div>
4166
4167<div class="doc_text">
4168
4169<h5>Syntax:</h5>
4170<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4171 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4172</pre>
4173
4174<h5>Overview:</h5>
4175
4176<p>
4177The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4178the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4179href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4180useful for implementing language features like scoped automatic variable sized
4181arrays in C99.
4182</p>
4183
4184<h5>Semantics:</h5>
4185
4186<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4187See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4188</p>
4189
4190</div>
4191
4192
4193<!-- _______________________________________________________________________ -->
4194<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4195 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4196</div>
4197
4198<div class="doc_text">
4199
4200<h5>Syntax:</h5>
4201<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4202 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4203</pre>
4204
4205<h5>Overview:</h5>
4206
4207
4208<p>
4209The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4210a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4211no
4212effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4213characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4214</p>
4215
4216<h5>Arguments:</h5>
4217
4218<p>
4219<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4220determining if the fetch should be for a read (0) or write (1), and
4221<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4222locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4223<tt>locality</tt> arguments must be constant integers.
4224</p>
4225
4226<h5>Semantics:</h5>
4227
4228<p>
4229This intrinsic does not modify the behavior of the program. In particular,
4230prefetches cannot trap and do not produce a value. On targets that support this
4231intrinsic, the prefetch can provide hints to the processor cache for better
4232performance.
4233</p>
4234
4235</div>
4236
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4237<!-- _______________________________________________________________________ -->
4238<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4239 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4240</div>
4241
4242<div class="doc_text">
4243
4244<h5>Syntax:</h5>
4245<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4246 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4247</pre>
4248
4249<h5>Overview:</h5>
4250
4251
4252<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4253The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4254(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4255code to simulators and other tools. The method is target specific, but it is
4256expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4257The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4258after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4259optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4260correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4261</p>
4262
4263<h5>Arguments:</h5>
4264
4265<p>
4266<tt>id</tt> is a numerical id identifying the marker.
4267</p>
4268
4269<h5>Semantics:</h5>
4270
4271<p>
4272This intrinsic does not modify the behavior of the program. Backends that do not
4273support this intrinisic may ignore it.
4274</p>
4275
4276</div>
4277
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4278<!-- _______________________________________________________________________ -->
4279<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4280 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4281</div>
4282
4283<div class="doc_text">
4284
4285<h5>Syntax:</h5>
4286<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4287 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4288</pre>
4289
4290<h5>Overview:</h5>
4291
4292
4293<p>
4294The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4295counter register (or similar low latency, high accuracy clocks) on those targets
4296that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4297As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4298should only be used for small timings.
4299</p>
4300
4301<h5>Semantics:</h5>
4302
4303<p>
4304When directly supported, reading the cycle counter should not modify any memory.
4305Implementations are allowed to either return a application specific value or a
4306system wide value. On backends without support, this is lowered to a constant 0.
4307</p>
4308
4309</div>
4310
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4311<!-- ======================================================================= -->
4312<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4313 <a name="int_libc">Standard C Library Intrinsics</a>
4314</div>
4315
4316<div class="doc_text">
4317<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4318LLVM provides intrinsics for a few important standard C library functions.
4319These intrinsics allow source-language front-ends to pass information about the
4320alignment of the pointer arguments to the code generator, providing opportunity
4321for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4322</p>
4323
4324</div>
4325
4326<!-- _______________________________________________________________________ -->
4327<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4328 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4329</div>
4330
4331<div class="doc_text">
4332
4333<h5>Syntax:</h5>
4334<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4335 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4336 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4337 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4338 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4339</pre>
4340
4341<h5>Overview:</h5>
4342
4343<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4344The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4345location to the destination location.
4346</p>
4347
4348<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4349Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4350intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4351</p>
4352
4353<h5>Arguments:</h5>
4354
4355<p>
4356The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4357the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4358specifying the number of bytes to copy, and the fourth argument is the alignment
4359of the source and destination locations.
4360</p>
4361
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4362<p>
4363If 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]4364the caller guarantees that both the source and destination pointers are aligned
4365to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4366</p>
4367
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4368<h5>Semantics:</h5>
4369
4370<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4371The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4372location to the destination location, which are not allowed to overlap. It
4373copies "len" bytes of memory over. If the argument is known to be aligned to
4374some boundary, this can be specified as the fourth argument, otherwise it should
4375be set to 0 or 1.
4376</p>
4377</div>
4378
4379
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4380<!-- _______________________________________________________________________ -->
4381<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4382 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4383</div>
4384
4385<div class="doc_text">
4386
4387<h5>Syntax:</h5>
4388<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4389 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4390 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4391 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4392 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4393</pre>
4394
4395<h5>Overview:</h5>
4396
4397<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4398The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4399location to the destination location. It is similar to the
4400'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4401</p>
4402
4403<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4404Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4405intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4406</p>
4407
4408<h5>Arguments:</h5>
4409
4410<p>
4411The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4412the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4413specifying the number of bytes to copy, and the fourth argument is the alignment
4414of the source and destination locations.
4415</p>
4416
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4417<p>
4418If 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]4419the caller guarantees that the source and destination pointers are aligned to
4420that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4421</p>
4422
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4423<h5>Semantics:</h5>
4424
4425<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4426The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4427location to the destination location, which may overlap. It
4428copies "len" bytes of memory over. If the argument is known to be aligned to
4429some boundary, this can be specified as the fourth argument, otherwise it should
4430be set to 0 or 1.
4431</p>
4432</div>
4433
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4434
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4435<!-- _______________________________________________________________________ -->
4436<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4437 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4438</div>
4439
4440<div class="doc_text">
4441
4442<h5>Syntax:</h5>
4443<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4444 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4445 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4446 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4447 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4448</pre>
4449
4450<h5>Overview:</h5>
4451
4452<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4453The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4454byte value.
4455</p>
4456
4457<p>
4458Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4459does not return a value, and takes an extra alignment argument.
4460</p>
4461
4462<h5>Arguments:</h5>
4463
4464<p>
4465The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4466byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4467argument specifying the number of bytes to fill, and the fourth argument is the
4468known alignment of destination location.
4469</p>
4470
4471<p>
4472If 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]4473the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4474</p>
4475
4476<h5>Semantics:</h5>
4477
4478<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4479The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4480the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4481destination location. If the argument is known to be aligned to some boundary,
4482this can be specified as the fourth argument, otherwise it should be set to 0 or
44831.
4484</p>
4485</div>
4486
4487
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4488<!-- _______________________________________________________________________ -->
4489<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4490 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4491</div>
4492
4493<div class="doc_text">
4494
4495<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4496<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4497floating point or vector of floating point type. Not all targets support all
4498types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4499<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4500 declare float @llvm.sqrt.f32(float %Val)
4501 declare double @llvm.sqrt.f64(double %Val)
4502 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4503 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4504 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4505</pre>
4506
4507<h5>Overview:</h5>
4508
4509<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4510The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4511returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4512<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4513negative numbers (which allows for better optimization).
4514</p>
4515
4516<h5>Arguments:</h5>
4517
4518<p>
4519The argument and return value are floating point numbers of the same type.
4520</p>
4521
4522<h5>Semantics:</h5>
4523
4524<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4525This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4526floating point number.
4527</p>
4528</div>
4529
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4530<!-- _______________________________________________________________________ -->
4531<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4532 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4533</div>
4534
4535<div class="doc_text">
4536
4537<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4538<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4539floating point or vector of floating point type. Not all targets support all
4540types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4541<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4542 declare float @llvm.powi.f32(float %Val, i32 %power)
4543 declare double @llvm.powi.f64(double %Val, i32 %power)
4544 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4545 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4546 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4547</pre>
4548
4549<h5>Overview:</h5>
4550
4551<p>
4552The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4553specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4554multiplications is not defined. When a vector of floating point type is
4555used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4556</p>
4557
4558<h5>Arguments:</h5>
4559
4560<p>
4561The second argument is an integer power, and the first is a value to raise to
4562that power.
4563</p>
4564
4565<h5>Semantics:</h5>
4566
4567<p>
4568This function returns the first value raised to the second power with an
4569unspecified sequence of rounding operations.</p>
4570</div>
4571
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4572<!-- _______________________________________________________________________ -->
4573<div class="doc_subsubsection">
4574 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4575</div>
4576
4577<div class="doc_text">
4578
4579<h5>Syntax:</h5>
4580<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4581floating point or vector of floating point type. Not all targets support all
4582types however.
4583<pre>
4584 declare float @llvm.sin.f32(float %Val)
4585 declare double @llvm.sin.f64(double %Val)
4586 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4587 declare fp128 @llvm.sin.f128(fp128 %Val)
4588 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4589</pre>
4590
4591<h5>Overview:</h5>
4592
4593<p>
4594The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4595</p>
4596
4597<h5>Arguments:</h5>
4598
4599<p>
4600The argument and return value are floating point numbers of the same type.
4601</p>
4602
4603<h5>Semantics:</h5>
4604
4605<p>
4606This function returns the sine of the specified operand, returning the
4607same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4608conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4609</div>
4610
4611<!-- _______________________________________________________________________ -->
4612<div class="doc_subsubsection">
4613 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4614</div>
4615
4616<div class="doc_text">
4617
4618<h5>Syntax:</h5>
4619<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4620floating point or vector of floating point type. Not all targets support all
4621types however.
4622<pre>
4623 declare float @llvm.cos.f32(float %Val)
4624 declare double @llvm.cos.f64(double %Val)
4625 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4626 declare fp128 @llvm.cos.f128(fp128 %Val)
4627 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4628</pre>
4629
4630<h5>Overview:</h5>
4631
4632<p>
4633The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4634</p>
4635
4636<h5>Arguments:</h5>
4637
4638<p>
4639The argument and return value are floating point numbers of the same type.
4640</p>
4641
4642<h5>Semantics:</h5>
4643
4644<p>
4645This function returns the cosine of the specified operand, returning the
4646same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4647conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4648</div>
4649
4650<!-- _______________________________________________________________________ -->
4651<div class="doc_subsubsection">
4652 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4653</div>
4654
4655<div class="doc_text">
4656
4657<h5>Syntax:</h5>
4658<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4659floating point or vector of floating point type. Not all targets support all
4660types however.
4661<pre>
4662 declare float @llvm.pow.f32(float %Val, float %Power)
4663 declare double @llvm.pow.f64(double %Val, double %Power)
4664 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4665 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4666 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4667</pre>
4668
4669<h5>Overview:</h5>
4670
4671<p>
4672The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4673specified (positive or negative) power.
4674</p>
4675
4676<h5>Arguments:</h5>
4677
4678<p>
4679The second argument is a floating point power, and the first is a value to
4680raise to that power.
4681</p>
4682
4683<h5>Semantics:</h5>
4684
4685<p>
4686This function returns the first value raised to the second power,
4687returning the
4688same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4689conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4690</div>
4691
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4692
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4693<!-- ======================================================================= -->
4694<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4695 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4696</div>
4697
4698<div class="doc_text">
4699<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4700LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4701These allow efficient code generation for some algorithms.
4702</p>
4703
4704</div>
4705
4706<!-- _______________________________________________________________________ -->
4707<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4708 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4709</div>
4710
4711<div class="doc_text">
4712
4713<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4714<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4715type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4716<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4717 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4718 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4719 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4720</pre>
4721
4722<h5>Overview:</h5>
4723
4724<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4725The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4726values with an even number of bytes (positive multiple of 16 bits). These are
4727useful for performing operations on data that is not in the target's native
4728byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4729</p>
4730
4731<h5>Semantics:</h5>
4732
4733<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4734The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4735and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4736intrinsic returns an i32 value that has the four bytes of the input i32
4737swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4738i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4739<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4740additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4741</p>
4742
4743</div>
4744
4745<!-- _______________________________________________________________________ -->
4746<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4747 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4748</div>
4749
4750<div class="doc_text">
4751
4752<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4753<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4754width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4755<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4756 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4757 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4758 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4759 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4760 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4761</pre>
4762
4763<h5>Overview:</h5>
4764
4765<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4766The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4767value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4768</p>
4769
4770<h5>Arguments:</h5>
4771
4772<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4773The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4774integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4775</p>
4776
4777<h5>Semantics:</h5>
4778
4779<p>
4780The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4781</p>
4782</div>
4783
4784<!-- _______________________________________________________________________ -->
4785<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4786 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4787</div>
4788
4789<div class="doc_text">
4790
4791<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4792<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4793integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4794<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4795 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4796 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4797 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4798 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4799 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4800</pre>
4801
4802<h5>Overview:</h5>
4803
4804<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4805The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4806leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4807</p>
4808
4809<h5>Arguments:</h5>
4810
4811<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4812The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4813integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4814</p>
4815
4816<h5>Semantics:</h5>
4817
4818<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4819The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4820in 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]4821of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4822</p>
4823</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4824
4825
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4826
4827<!-- _______________________________________________________________________ -->
4828<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4829 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4830</div>
4831
4832<div class="doc_text">
4833
4834<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4835<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4836integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4837<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4838 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4839 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4840 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4841 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4842 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4843</pre>
4844
4845<h5>Overview:</h5>
4846
4847<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4848The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4849trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4850</p>
4851
4852<h5>Arguments:</h5>
4853
4854<p>
4855The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4856integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4857</p>
4858
4859<h5>Semantics:</h5>
4860
4861<p>
4862The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4863in a variable. If the src == 0 then the result is the size in bits of the type
4864of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4865</p>
4866</div>
4867
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4868<!-- _______________________________________________________________________ -->
4869<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4870 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4871</div>
4872
4873<div class="doc_text">
4874
4875<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4876<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4877on any integer bit width.
4878<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4879 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4880 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4881</pre>
4882
4883<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4884<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4885range of bits from an integer value and returns them in the same bit width as
4886the original value.</p>
4887
4888<h5>Arguments:</h5>
4889<p>The first argument, <tt>%val</tt> and the result may be integer types of
4890any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4891arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4892
4893<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4894<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4895of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4896<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4897operates in forward mode.</p>
4898<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4899right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4900only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4901<ol>
4902 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4903 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4904 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4905 to determine the number of bits to retain.</li>
4906 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4907 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4908</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]4909<p>In reverse mode, a similar computation is made except that the bits are
4910returned in the reverse order. So, for example, if <tt>X</tt> has the value
4911<tt>i16 0x0ACF (101011001111)</tt> and we apply
4912<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4913<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4914</div>
4915
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4916<div class="doc_subsubsection">
4917 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4918</div>
4919
4920<div class="doc_text">
4921
4922<h5>Syntax:</h5>
4923<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4924on any integer bit width.
4925<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4926 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4927 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4928</pre>
4929
4930<h5>Overview:</h5>
4931<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4932of bits in an integer value with another integer value. It returns the integer
4933with the replaced bits.</p>
4934
4935<h5>Arguments:</h5>
4936<p>The first argument, <tt>%val</tt> and the result may be integer types of
4937any bit width but they must have the same bit width. <tt>%val</tt> is the value
4938whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4939integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4940type since they specify only a bit index.</p>
4941
4942<h5>Semantics:</h5>
4943<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4944of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4945<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4946operates in forward mode.</p>
4947<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4948truncating it down to the size of the replacement area or zero extending it
4949up to that size.</p>
4950<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4951are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4952in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4953to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4954<p>In reverse mode, a similar computation is made except that the bits are
4955reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4956<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]4957<h5>Examples:</h5>
4958<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4959 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4960 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4961 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4962 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4963 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4964</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4965</div>
4966
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4967<!-- ======================================================================= -->
4968<div class="doc_subsection">
4969 <a name="int_debugger">Debugger Intrinsics</a>
4970</div>
4971
4972<div class="doc_text">
4973<p>
4974The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4975are described in the <a
4976href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4977Debugging</a> document.
4978</p>
4979</div>
4980
4981
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4982<!-- ======================================================================= -->
4983<div class="doc_subsection">
4984 <a name="int_eh">Exception Handling Intrinsics</a>
4985</div>
4986
4987<div class="doc_text">
4988<p> The LLVM exception handling intrinsics (which all start with
4989<tt>llvm.eh.</tt> prefix), are described in the <a
4990href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4991Handling</a> document. </p>
4992</div>
4993
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]4994<!-- ======================================================================= -->
4995<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]4996 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]4997</div>
4998
4999<div class="doc_text">
5000<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5001 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5002 the <tt>nest</tt> attribute, from a function. The result is a callable
5003 function pointer lacking the nest parameter - the caller does not need
5004 to provide a value for it. Instead, the value to use is stored in
5005 advance in a "trampoline", a block of memory usually allocated
5006 on the stack, which also contains code to splice the nest value into the
5007 argument list. This is used to implement the GCC nested function address
5008 extension.
5009</p>
5010<p>
5011 For example, if the function is
5012 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5013 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5014<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5015 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5016 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5017 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5018 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5019</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5020 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5021 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5022</div>
5023
5024<!-- _______________________________________________________________________ -->
5025<div class="doc_subsubsection">
5026 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5027</div>
5028<div class="doc_text">
5029<h5>Syntax:</h5>
5030<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5031declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5032</pre>
5033<h5>Overview:</h5>
5034<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5035 This fills the memory pointed to by <tt>tramp</tt> with code
5036 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5037</p>
5038<h5>Arguments:</h5>
5039<p>
5040 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5041 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5042 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5043 intrinsic. Note that the size and the alignment are target-specific - LLVM
5044 currently provides no portable way of determining them, so a front-end that
5045 generates this intrinsic needs to have some target-specific knowledge.
5046 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5047</p>
5048<h5>Semantics:</h5>
5049<p>
5050 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5051 dependent code, turning it into a function. A pointer to this function is
5052 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5053 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5054 before being called. The new function's signature is the same as that of
5055 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5056 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5057 of pointer type. Calling the new function is equivalent to calling
5058 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5059 missing <tt>nest</tt> argument. If, after calling
5060 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5061 modified, then the effect of any later call to the returned function pointer is
5062 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5063</p>
5064</div>
5065
5066<!-- ======================================================================= -->
5067<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5068 <a name="int_general">General Intrinsics</a>
5069</div>
5070
5071<div class="doc_text">
5072<p> This class of intrinsics is designed to be generic and has
5073no specific purpose. </p>
5074</div>
5075
5076<!-- _______________________________________________________________________ -->
5077<div class="doc_subsubsection">
5078 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5079</div>
5080
5081<div class="doc_text">
5082
5083<h5>Syntax:</h5>
5084<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5085 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5086</pre>
5087
5088<h5>Overview:</h5>
5089
5090<p>
5091The '<tt>llvm.var.annotation</tt>' intrinsic
5092</p>
5093
5094<h5>Arguments:</h5>
5095
5096<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5097The first argument is a pointer to a value, the second is a pointer to a
5098global string, the third is a pointer to a global string which is the source
5099file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5100</p>
5101
5102<h5>Semantics:</h5>
5103
5104<p>
5105This intrinsic allows annotation of local variables with arbitrary strings.
5106This can be useful for special purpose optimizations that want to look for these
5107 annotations. These have no other defined use, they are ignored by code
5108 generation and optimization.
5109</div>
5110
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5111<!-- _______________________________________________________________________ -->
5112<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5113 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5114</div>
5115
5116<div class="doc_text">
5117
5118<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5119<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5120any integer bit width.
5121</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5122<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5123 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5124 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5125 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5126 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5127 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5128</pre>
5129
5130<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5131
5132<p>
5133The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5134</p>
5135
5136<h5>Arguments:</h5>
5137
5138<p>
5139The first argument is an integer value (result of some expression),
5140the second is a pointer to a global string, the third is a pointer to a global
5141string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5142It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5143</p>
5144
5145<h5>Semantics:</h5>
5146
5147<p>
5148This intrinsic allows annotations to be put on arbitrary expressions
5149with arbitrary strings. This can be useful for special purpose optimizations
5150that want to look for these annotations. These have no other defined use, they
5151are ignored by code generation and optimization.
5152</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5153
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5154<!-- *********************************************************************** -->
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5156<address>
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5161
5162 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5163 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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