Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 47507ded8c324a4426f5a872be807f068184f4c8 / . / docs / LangRef.html
blob: fa5019370a4680f322c9e754e18f7e304cc2dd61 [file] [log] [blame]
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
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>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]31 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]32 </ol>
33 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]50 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]52 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]53 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]54 </ol>
55 </li>
56 </ol>
57 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]112 </ol>
113 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]114 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
117 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
118 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]119 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
120 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
121 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 </ol>
123 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]124 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]125 <ol>
126 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
127 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
129 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
130 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]131 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
132 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
133 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]135 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
136 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]137 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]138 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#otherops">Other Operations</a>
140 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]141 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
142 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]144 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]146 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]147 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]149 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]151 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]152 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
154 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]155 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
156 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
157 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 </ol>
159 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
161 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]162 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
163 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
164 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]167 <li><a href="#int_codegen">Code Generator Intrinsics</a>
168 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]169 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
170 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
171 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
172 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
173 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
174 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
175 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]176 </ol>
177 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]178 <li><a href="#int_libc">Standard C Library Intrinsics</a>
179 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]180 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
181 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
183 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
184 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]185 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
186 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
187 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]188 </ol>
189 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]190 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]191 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]192 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]193 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
194 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
195 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]196 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
197 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]198 </ol>
199 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]200 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]201 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]202 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]203 <ol>
204 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]205 </ol>
206 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]207 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]208 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]209 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]210 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]211 </ol>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]212 <ol>
213 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]214 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]215 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]216 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]219</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]220
221<div class="doc_author">
222 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
223 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]224</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]226<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227<div class="doc_section"> <a name="abstract">Abstract </a></div>
228<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]230<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]231<p>This document is a reference manual for the LLVM assembly language.
232LLVM is an SSA based representation that provides type safety,
233low-level operations, flexibility, and the capability of representing
234'all' high-level languages cleanly. It is the common code
235representation used throughout all phases of the LLVM compilation
236strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]237</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]238
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]239<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<div class="doc_section"> <a name="introduction">Introduction</a> </div>
241<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]245<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]246different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]247representation (suitable for fast loading by a Just-In-Time compiler),
248and as a human readable assembly language representation. This allows
249LLVM to provide a powerful intermediate representation for efficient
250compiler transformations and analysis, while providing a natural means
251to debug and visualize the transformations. The three different forms
252of LLVM are all equivalent. This document describes the human readable
253representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]255<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256while being expressive, typed, and extensible at the same time. It
257aims to be a "universal IR" of sorts, by being at a low enough level
258that high-level ideas may be cleanly mapped to it (similar to how
259microprocessors are "universal IR's", allowing many source languages to
260be mapped to them). By providing type information, LLVM can be used as
261the target of optimizations: for example, through pointer analysis, it
262can be proven that a C automatic variable is never accessed outside of
263the current function... allowing it to be promoted to a simple SSA
264value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]266</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]268<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]269<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]271<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]273<p>It is important to note that this document describes 'well formed'
274LLVM assembly language. There is a difference between what the parser
275accepts and what is considered 'well formed'. For example, the
276following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]277
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]278<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]279<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]280%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]282</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]283
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]284<p>...because the definition of <tt>%x</tt> does not dominate all of
285its uses. The LLVM infrastructure provides a verification pass that may
286be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]287automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]288the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]289by the verifier pass indicate bugs in transformation passes or input to
290the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]291</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]293<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]295<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]297<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]298
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]299<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]300
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]301 <p>LLVM identifiers come in two basic types: global and local. Global
302 identifiers (functions, global variables) begin with the @ character. Local
303 identifiers (register names, types) begin with the % character. Additionally,
304 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]305
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]306<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]307 <li>Named values are represented as a string of characters with their prefix.
308 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
309 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]310 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]311 with quotes. In this way, anything except a <tt>&quot;</tt> character can
312 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]313
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]314 <li>Unnamed values are represented as an unsigned numeric value with their
315 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]316
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]317 <li>Constants, which are described in a <a href="#constants">section about
318 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]320
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]321<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]322don't need to worry about name clashes with reserved words, and the set of
323reserved words may be expanded in the future without penalty. Additionally,
324unnamed identifiers allow a compiler to quickly come up with a temporary
325variable without having to avoid symbol table conflicts.</p>
326
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]327<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]328languages. There are keywords for different opcodes
329('<tt><a href="#i_add">add</a></tt>',
330 '<tt><a href="#i_bitcast">bitcast</a></tt>',
331 '<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]332href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]333and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]334none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
336<p>Here is an example of LLVM code to multiply the integer variable
337'<tt>%X</tt>' by 8:</p>
338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]340
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]341<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]343%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]345</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]347<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]348
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]349<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]350<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]351%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]352</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]353</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]354
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]355<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]356
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]357<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]358<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]359<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
360<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
361%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]362</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]363</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]364
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
366important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]368<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]369
370 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
371 line.</li>
372
373 <li>Unnamed temporaries are created when the result of a computation is not
374 assigned to a named value.</li>
375
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]376 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]377
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]378</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]379
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]380<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]381demonstrating instructions, we will follow an instruction with a comment that
382defines the type and name of value produced. Comments are shown in italic
383text.</p>
384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]385</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386
387<!-- *********************************************************************** -->
388<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
389<!-- *********************************************************************** -->
390
391<!-- ======================================================================= -->
392<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
393</div>
394
395<div class="doc_text">
396
397<p>LLVM programs are composed of "Module"s, each of which is a
398translation unit of the input programs. Each module consists of
399functions, global variables, and symbol table entries. Modules may be
400combined together with the LLVM linker, which merges function (and
401global variable) definitions, resolves forward declarations, and merges
402symbol table entries. Here is an example of the "hello world" module:</p>
403
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]404<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]405<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]406<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
407 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]408
409<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]410<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]411
412<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]413define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]414 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]415 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]416 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]417
418 <i>; Call puts function to write out the string to stdout...</i>
419 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]420 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]421 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]422 href="#i_ret">ret</a> i32 0<br>}<br>
423</pre>
424</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]425
426<p>This example is made up of a <a href="#globalvars">global variable</a>
427named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
428function, and a <a href="#functionstructure">function definition</a>
429for "<tt>main</tt>".</p>
430
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431<p>In general, a module is made up of a list of global values,
432where both functions and global variables are global values. Global values are
433represented by a pointer to a memory location (in this case, a pointer to an
434array of char, and a pointer to a function), and have one of the following <a
435href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]436
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437</div>
438
439<!-- ======================================================================= -->
440<div class="doc_subsection">
441 <a name="linkage">Linkage Types</a>
442</div>
443
444<div class="doc_text">
445
446<p>
447All Global Variables and Functions have one of the following types of linkage:
448</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]449
450<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]452 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
454 <dd>Global values with internal linkage are only directly accessible by
455 objects in the current module. In particular, linking code into a module with
456 an internal global value may cause the internal to be renamed as necessary to
457 avoid collisions. Because the symbol is internal to the module, all
458 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]459 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]460 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]462 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]464 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
465 the same name when linkage occurs. This is typically used to implement
466 inline functions, templates, or other code which must be generated in each
467 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
468 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
473 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
474 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]475 used for globals that may be emitted in multiple translation units, but that
476 are not guaranteed to be emitted into every translation unit that uses them.
477 One example of this are common globals in C, such as "<tt>int X;</tt>" at
478 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]479 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]481 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]482
483 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
484 pointer to array type. When two global variables with appending linkage are
485 linked together, the two global arrays are appended together. This is the
486 LLVM, typesafe, equivalent of having the system linker append together
487 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]489
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]490 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
491 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
492 until linked, if not linked, the symbol becomes null instead of being an
493 undefined reference.
494 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]495
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]497
498 <dd>If none of the above identifiers are used, the global is externally
499 visible, meaning that it participates in linkage and can be used to resolve
500 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]502</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]503
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]504 <p>
505 The next two types of linkage are targeted for Microsoft Windows platform
506 only. They are designed to support importing (exporting) symbols from (to)
507 DLLs.
508 </p>
509
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]510 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]511 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
512
513 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
514 or variable via a global pointer to a pointer that is set up by the DLL
515 exporting the symbol. On Microsoft Windows targets, the pointer name is
516 formed by combining <code>_imp__</code> and the function or variable name.
517 </dd>
518
519 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
520
521 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
522 pointer to a pointer in a DLL, so that it can be referenced with the
523 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
524 name is formed by combining <code>_imp__</code> and the function or variable
525 name.
526 </dd>
527
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528</dl>
529
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]530<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]531variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
532variable and was linked with this one, one of the two would be renamed,
533preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
534external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]535outside of the current module.</p>
536<p>It is illegal for a function <i>declaration</i>
537to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]538or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]539<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
540linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]541</div>
542
543<!-- ======================================================================= -->
544<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]545 <a name="callingconv">Calling Conventions</a>
546</div>
547
548<div class="doc_text">
549
550<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
551and <a href="#i_invoke">invokes</a> can all have an optional calling convention
552specified for the call. The calling convention of any pair of dynamic
553caller/callee must match, or the behavior of the program is undefined. The
554following calling conventions are supported by LLVM, and more may be added in
555the future:</p>
556
557<dl>
558 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
559
560 <dd>This calling convention (the default if no other calling convention is
561 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]562 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]563 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]564 </dd>
565
566 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
567
568 <dd>This calling convention attempts to make calls as fast as possible
569 (e.g. by passing things in registers). This calling convention allows the
570 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]571 without having to conform to an externally specified ABI. Implementations of
572 this convention should allow arbitrary tail call optimization to be supported.
573 This calling convention does not support varargs and requires the prototype of
574 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]575 </dd>
576
577 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
578
579 <dd>This calling convention attempts to make code in the caller as efficient
580 as possible under the assumption that the call is not commonly executed. As
581 such, these calls often preserve all registers so that the call does not break
582 any live ranges in the caller side. This calling convention does not support
583 varargs and requires the prototype of all callees to exactly match the
584 prototype of the function definition.
585 </dd>
586
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]587 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]588
589 <dd>Any calling convention may be specified by number, allowing
590 target-specific calling conventions to be used. Target specific calling
591 conventions start at 64.
592 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]593</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]594
595<p>More calling conventions can be added/defined on an as-needed basis, to
596support pascal conventions or any other well-known target-independent
597convention.</p>
598
599</div>
600
601<!-- ======================================================================= -->
602<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]603 <a name="visibility">Visibility Styles</a>
604</div>
605
606<div class="doc_text">
607
608<p>
609All Global Variables and Functions have one of the following visibility styles:
610</p>
611
612<dl>
613 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
614
615 <dd>On ELF, default visibility means that the declaration is visible to other
616 modules and, in shared libraries, means that the declared entity may be
617 overridden. On Darwin, default visibility means that the declaration is
618 visible to other modules. Default visibility corresponds to "external
619 linkage" in the language.
620 </dd>
621
622 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
623
624 <dd>Two declarations of an object with hidden visibility refer to the same
625 object if they are in the same shared object. Usually, hidden visibility
626 indicates that the symbol will not be placed into the dynamic symbol table,
627 so no other module (executable or shared library) can reference it
628 directly.
629 </dd>
630
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]631 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
632
633 <dd>On ELF, protected visibility indicates that the symbol will be placed in
634 the dynamic symbol table, but that references within the defining module will
635 bind to the local symbol. That is, the symbol cannot be overridden by another
636 module.
637 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]638</dl>
639
640</div>
641
642<!-- ======================================================================= -->
643<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]644 <a name="globalvars">Global Variables</a>
645</div>
646
647<div class="doc_text">
648
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]649<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]650instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]651an explicit section to be placed in, and may have an optional explicit alignment
652specified. A variable may be defined as "thread_local", which means that it
653will not be shared by threads (each thread will have a separated copy of the
654variable). A variable may be defined as a global "constant," which indicates
655that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]656optimization, allowing the global data to be placed in the read-only section of
657an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]658cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]659
660<p>
661LLVM explicitly allows <em>declarations</em> of global variables to be marked
662constant, even if the final definition of the global is not. This capability
663can be used to enable slightly better optimization of the program, but requires
664the language definition to guarantee that optimizations based on the
665'constantness' are valid for the translation units that do not include the
666definition.
667</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]668
669<p>As SSA values, global variables define pointer values that are in
670scope (i.e. they dominate) all basic blocks in the program. Global
671variables always define a pointer to their "content" type because they
672describe a region of memory, and all memory objects in LLVM are
673accessed through pointers.</p>
674
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]675<p>A global variable may be declared to reside in a target-specifc numbered
676address space. For targets that support them, address spaces may affect how
677optimizations are performed and/or what target instructions are used to access
Christopher Lambd49e18d2007-12-12 08:44:39 +0000[diff] [blame]678the variable. The default address space is zero. The address space qualifier
679must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]680
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]681<p>LLVM allows an explicit section to be specified for globals. If the target
682supports it, it will emit globals to the section specified.</p>
683
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]684<p>An explicit alignment may be specified for a global. If not present, or if
685the alignment is set to zero, the alignment of the global is set by the target
686to whatever it feels convenient. If an explicit alignment is specified, the
687global is forced to have at least that much alignment. All alignments must be
688a power of 2.</p>
689
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]690<p>For example, the following defines a global in a numbered address space with
691an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]692
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]693<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]694<pre>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]695@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]696</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]697</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]698
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]699</div>
700
701
702<!-- ======================================================================= -->
703<div class="doc_subsection">
704 <a name="functionstructure">Functions</a>
705</div>
706
707<div class="doc_text">
708
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]709<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
710an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]711<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]712<a href="#callingconv">calling convention</a>, a return type, an optional
713<a href="#paramattrs">parameter attribute</a> for the return type, a function
714name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]715<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]716optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]717opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]718
719LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
720optional <a href="#linkage">linkage type</a>, an optional
721<a href="#visibility">visibility style</a>, an optional
722<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]723<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]724name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]725<a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]726
727<p>A function definition contains a list of basic blocks, forming the CFG for
728the function. Each basic block may optionally start with a label (giving the
729basic block a symbol table entry), contains a list of instructions, and ends
730with a <a href="#terminators">terminator</a> instruction (such as a branch or
731function return).</p>
732
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]733<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]734executed on entrance to the function, and it is not allowed to have predecessor
735basic blocks (i.e. there can not be any branches to the entry block of a
736function). Because the block can have no predecessors, it also cannot have any
737<a href="#i_phi">PHI nodes</a>.</p>
738
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]739<p>LLVM allows an explicit section to be specified for functions. If the target
740supports it, it will emit functions to the section specified.</p>
741
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]742<p>An explicit alignment may be specified for a function. If not present, or if
743the alignment is set to zero, the alignment of the function is set by the target
744to whatever it feels convenient. If an explicit alignment is specified, the
745function is forced to have at least that much alignment. All alignments must be
746a power of 2.</p>
747
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]748</div>
749
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
753 <a name="aliasstructure">Aliases</a>
754</div>
755<div class="doc_text">
756 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]757 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]758 optional <a href="#linkage">linkage type</a>, and an
759 optional <a href="#visibility">visibility style</a>.</p>
760
761 <h5>Syntax:</h5>
762
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]763<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]764<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]765@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]766</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]767</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]768
769</div>
770
771
772
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]773<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]774<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
775<div class="doc_text">
776 <p>The return type and each parameter of a function type may have a set of
777 <i>parameter attributes</i> associated with them. Parameter attributes are
778 used to communicate additional information about the result or parameters of
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]779 a function. Parameter attributes are considered to be part of the function,
780 not of the function type, so functions with different parameter attributes
781 can have the same function type.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]782
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]783 <p>Parameter attributes are simple keywords that follow the type specified. If
784 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]785 example:</p>
786
787<div class="doc_code">
788<pre>
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]789declare i32 @printf(i8* noalias , ...) nounwind
790declare i32 @atoi(i8*) nounwind readonly
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]791</pre>
792</div>
793
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]794 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
795 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]796
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]797 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]798 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]799 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]800 <dd>This indicates that the parameter should be zero extended just before
801 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]802
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]803 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]804 <dd>This indicates that the parameter should be sign extended just before
805 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]806
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]807 <dt><tt>inreg</tt></dt>
808 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]809 possible) during assembling function call. Support for this attribute is
810 target-specific</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]811
812 <dt><tt>byval</tt></dt>
813 <dd>This indicates that the pointer parameter is really an aggregate that
814 was passed by value to the function. The attribute implies that a hidden
815 copy of the struct is made between the caller and the callee, so the
816 callee is unable to modify the struct in the callee. This attribute is only
817 valid on llvm pointer arguments.</dd>
818
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]819 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]820 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]821 that is the return value of the function in the source program.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]822
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]823 <dt><tt>noalias</tt></dt>
824 <dd>This indicates that the parameter not alias any other object or any
825 other "noalias" objects during the function call.
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]826
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]827 <dt><tt>noreturn</tt></dt>
828 <dd>This function attribute indicates that the function never returns. This
829 indicates to LLVM that every call to this function should be treated as if
830 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]831
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]832 <dt><tt>nounwind</tt></dt>
833 <dd>This function attribute indicates that the function type does not use
834 the unwind instruction and does not allow stack unwinding to propagate
835 through it.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame^]836
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]837 <dt><tt>nest</tt></dt>
838 <dd>This indicates that the parameter can be excised using the
839 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]840 <dt><tt>readonly</tt></dt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]841 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]842 except for producing a return value or throwing an exception. The value
843 returned must only depend on the function arguments and/or global variables.
844 It may use values obtained by dereferencing pointers.</dd>
845 <dt><tt>readnone</tt></dt>
846 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]847 function, but in addition it is not allowed to dereference any pointer arguments
848 or global variables.
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]849 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]850
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]851</div>
852
853<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]854<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]855 <a name="gc">Garbage Collector Names</a>
856</div>
857
858<div class="doc_text">
859<p>Each function may specify a garbage collector name, which is simply a
860string.</p>
861
862<div class="doc_code"><pre
863>define void @f() gc "name" { ...</pre></div>
864
865<p>The compiler declares the supported values of <i>name</i>. Specifying a
866collector which will cause the compiler to alter its output in order to support
867the named garbage collection algorithm.</p>
868</div>
869
870<!-- ======================================================================= -->
871<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]872 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]873</div>
874
875<div class="doc_text">
876<p>
877Modules may contain "module-level inline asm" blocks, which corresponds to the
878GCC "file scope inline asm" blocks. These blocks are internally concatenated by
879LLVM and treated as a single unit, but may be separated in the .ll file if
880desired. The syntax is very simple:
881</p>
882
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]883<div class="doc_code">
884<pre>
885module asm "inline asm code goes here"
886module asm "more can go here"
887</pre>
888</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]889
890<p>The strings can contain any character by escaping non-printable characters.
891 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
892 for the number.
893</p>
894
895<p>
896 The inline asm code is simply printed to the machine code .s file when
897 assembly code is generated.
898</p>
899</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]900
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]901<!-- ======================================================================= -->
902<div class="doc_subsection">
903 <a name="datalayout">Data Layout</a>
904</div>
905
906<div class="doc_text">
907<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]908data is to be laid out in memory. The syntax for the data layout is simply:</p>
909<pre> target datalayout = "<i>layout specification</i>"</pre>
910<p>The <i>layout specification</i> consists of a list of specifications
911separated by the minus sign character ('-'). Each specification starts with a
912letter and may include other information after the letter to define some
913aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]914<dl>
915 <dt><tt>E</tt></dt>
916 <dd>Specifies that the target lays out data in big-endian form. That is, the
917 bits with the most significance have the lowest address location.</dd>
918 <dt><tt>e</tt></dt>
919 <dd>Specifies that hte target lays out data in little-endian form. That is,
920 the bits with the least significance have the lowest address location.</dd>
921 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
922 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
923 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
924 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
925 too.</dd>
926 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
927 <dd>This specifies the alignment for an integer type of a given bit
928 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
929 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
930 <dd>This specifies the alignment for a vector type of a given bit
931 <i>size</i>.</dd>
932 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
933 <dd>This specifies the alignment for a floating point type of a given bit
934 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
935 (double).</dd>
936 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
937 <dd>This specifies the alignment for an aggregate type of a given bit
938 <i>size</i>.</dd>
939</dl>
940<p>When constructing the data layout for a given target, LLVM starts with a
941default set of specifications which are then (possibly) overriden by the
942specifications in the <tt>datalayout</tt> keyword. The default specifications
943are given in this list:</p>
944<ul>
945 <li><tt>E</tt> - big endian</li>
946 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
947 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
948 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
949 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
950 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
951 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
952 alignment of 64-bits</li>
953 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
954 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
955 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
956 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
957 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
958</ul>
959<p>When llvm is determining the alignment for a given type, it uses the
960following rules:
961<ol>
962 <li>If the type sought is an exact match for one of the specifications, that
963 specification is used.</li>
964 <li>If no match is found, and the type sought is an integer type, then the
965 smallest integer type that is larger than the bitwidth of the sought type is
966 used. If none of the specifications are larger than the bitwidth then the the
967 largest integer type is used. For example, given the default specifications
968 above, the i7 type will use the alignment of i8 (next largest) while both
969 i65 and i256 will use the alignment of i64 (largest specified).</li>
970 <li>If no match is found, and the type sought is a vector type, then the
971 largest vector type that is smaller than the sought vector type will be used
972 as a fall back. This happens because <128 x double> can be implemented in
973 terms of 64 <2 x double>, for example.</li>
974</ol>
975</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]977<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]978<div class="doc_section"> <a name="typesystem">Type System</a> </div>
979<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]980
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]981<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]982
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]983<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]984intermediate representation. Being typed enables a number of
985optimizations to be performed on the IR directly, without having to do
986extra analyses on the side before the transformation. A strong type
987system makes it easier to read the generated code and enables novel
988analyses and transformations that are not feasible to perform on normal
989three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]990
991</div>
992
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]993<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]994<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]995Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]996<div class="doc_text">
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]997<p>The types fall into a few useful
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]998classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]999
1000<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1001 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1002 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1003 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1004 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1005 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1006 </tr>
1007 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1008 <td><a href="#t_floating">floating point</a></td>
1009 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1010 </tr>
1011 <tr>
1012 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1013 <td><a href="#t_integer">integer</a>,
1014 <a href="#t_floating">floating point</a>,
1015 <a href="#t_pointer">pointer</a>,
1016 <a href="#t_vector">vector</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1017 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1018 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1019 <tr>
1020 <td><a href="#t_primitive">primitive</a></td>
1021 <td><a href="#t_label">label</a>,
1022 <a href="#t_void">void</a>,
1023 <a href="#t_integer">integer</a>,
1024 <a href="#t_floating">floating point</a>.</td>
1025 </tr>
1026 <tr>
1027 <td><a href="#t_derived">derived</a></td>
1028 <td><a href="#t_integer">integer</a>,
1029 <a href="#t_array">array</a>,
1030 <a href="#t_function">function</a>,
1031 <a href="#t_pointer">pointer</a>,
1032 <a href="#t_struct">structure</a>,
1033 <a href="#t_pstruct">packed structure</a>,
1034 <a href="#t_vector">vector</a>,
1035 <a href="#t_opaque">opaque</a>.
1036 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1037 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1038</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1039
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1040<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1041most important. Values of these types are the only ones which can be
1042produced by instructions, passed as arguments, or used as operands to
1043instructions. This means that all structures and arrays must be
1044manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1045</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1046
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1047<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1048<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1049
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1050<div class="doc_text">
1051<p>The primitive types are the fundamental building blocks of the LLVM
1052system.</p>
1053
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1054</div>
1055
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1056<!-- _______________________________________________________________________ -->
1057<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1058
1059<div class="doc_text">
1060 <table>
1061 <tbody>
1062 <tr><th>Type</th><th>Description</th></tr>
1063 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1064 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1065 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1066 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1067 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1068 </tbody>
1069 </table>
1070</div>
1071
1072<!-- _______________________________________________________________________ -->
1073<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1074
1075<div class="doc_text">
1076<h5>Overview:</h5>
1077<p>The void type does not represent any value and has no size.</p>
1078
1079<h5>Syntax:</h5>
1080
1081<pre>
1082 void
1083</pre>
1084</div>
1085
1086<!-- _______________________________________________________________________ -->
1087<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1088
1089<div class="doc_text">
1090<h5>Overview:</h5>
1091<p>The label type represents code labels.</p>
1092
1093<h5>Syntax:</h5>
1094
1095<pre>
1096 label
1097</pre>
1098</div>
1099
1100
1101<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1102<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1103
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1104<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1105
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1106<p>The real power in LLVM comes from the derived types in the system.
1107This is what allows a programmer to represent arrays, functions,
1108pointers, and other useful types. Note that these derived types may be
1109recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1110
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1111</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1112
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1113<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1114<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1115
1116<div class="doc_text">
1117
1118<h5>Overview:</h5>
1119<p>The integer type is a very simple derived type that simply specifies an
1120arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11212^23-1 (about 8 million) can be specified.</p>
1122
1123<h5>Syntax:</h5>
1124
1125<pre>
1126 iN
1127</pre>
1128
1129<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1130value.</p>
1131
1132<h5>Examples:</h5>
1133<table class="layout">
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1134 <tbody>
1135 <tr>
1136 <td><tt>i1</tt></td>
1137 <td>a single-bit integer.</td>
1138 </tr><tr>
1139 <td><tt>i32</tt></td>
1140 <td>a 32-bit integer.</td>
1141 </tr><tr>
1142 <td><tt>i1942652</tt></td>
1143 <td>a really big integer of over 1 million bits.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1144 </tr>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1145 </tbody>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1146</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1147</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1148
1149<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1150<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1151
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1152<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1153
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1154<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1155
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1156<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1157sequentially in memory. The array type requires a size (number of
1158elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1159
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1160<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1161
1162<pre>
1163 [&lt;# elements&gt; x &lt;elementtype&gt;]
1164</pre>
1165
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1166<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1167be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1168
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1169<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1170<table class="layout">
1171 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1172 <td class="left"><tt>[40 x i32]</tt></td>
1173 <td class="left">Array of 40 32-bit integer values.</td>
1174 </tr>
1175 <tr class="layout">
1176 <td class="left"><tt>[41 x i32]</tt></td>
1177 <td class="left">Array of 41 32-bit integer values.</td>
1178 </tr>
1179 <tr class="layout">
1180 <td class="left"><tt>[4 x i8]</tt></td>
1181 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1182 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1183</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1184<p>Here are some examples of multidimensional arrays:</p>
1185<table class="layout">
1186 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1187 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1188 <td class="left">3x4 array of 32-bit integer values.</td>
1189 </tr>
1190 <tr class="layout">
1191 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1192 <td class="left">12x10 array of single precision floating point values.</td>
1193 </tr>
1194 <tr class="layout">
1195 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1196 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1197 </tr>
1198</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1199
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1200<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1201length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1202LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1203As a special case, however, zero length arrays are recognized to be variable
1204length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1205type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1207</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1208
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1209<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1210<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1211<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1212<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1213<p>The function type can be thought of as a function signature. It
1214consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1215Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1216(which are structures of pointers to functions), for indirect function
1217calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1218<p>
1219The return type of a function type cannot be an aggregate type.
1220</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1221<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1222<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1223<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]1224specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1225which indicates that the function takes a variable number of arguments.
1226Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1227 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1228<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1229<table class="layout">
1230 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1231 <td class="left"><tt>i32 (i32)</tt></td>
1232 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1233 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1234 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1235 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1236 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1237 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1238 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1239 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1240 <tt>float</tt>.
1241 </td>
1242 </tr><tr class="layout">
1243 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1244 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1245 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1246 which returns an integer. This is the signature for <tt>printf</tt> in
1247 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1248 </td>
1249 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1250</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1252</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1253<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1254<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1255<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1256<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1257<p>The structure type is used to represent a collection of data members
1258together in memory. The packing of the field types is defined to match
1259the ABI of the underlying processor. The elements of a structure may
1260be any type that has a size.</p>
1261<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1262and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1263field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1264instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1266<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1267<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1268<table class="layout">
1269 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1270 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1271 <td class="left">A triple of three <tt>i32</tt> values</td>
1272 </tr><tr class="layout">
1273 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1274 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1275 second element is a <a href="#t_pointer">pointer</a> to a
1276 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1277 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1278 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1279</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1280</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1281
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1282<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1283<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1284</div>
1285<div class="doc_text">
1286<h5>Overview:</h5>
1287<p>The packed structure type is used to represent a collection of data members
1288together in memory. There is no padding between fields. Further, the alignment
1289of a packed structure is 1 byte. The elements of a packed structure may
1290be any type that has a size.</p>
1291<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1292and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1293field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1294instruction.</p>
1295<h5>Syntax:</h5>
1296<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1297<h5>Examples:</h5>
1298<table class="layout">
1299 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1300 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1301 <td class="left">A triple of three <tt>i32</tt> values</td>
1302 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1303 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1304 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1305 second element is a <a href="#t_pointer">pointer</a> to a
1306 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1307 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1308 </tr>
1309</table>
1310</div>
1311
1312<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1313<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1314<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1315<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1316<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1317reference to another object, which must live in memory. Pointer types may have
1318an optional address space attribute defining the target-specific numbered
1319address space where the pointed-to object resides. The default address space is
1320zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1321<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1322<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1323<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1324<table class="layout">
1325 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1326 <td class="left"><tt>[4x i32]*</tt></td>
1327 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1328 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1329 </tr>
1330 <tr class="layout">
1331 <td class="left"><tt>i32 (i32 *) *</tt></td>
1332 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1333 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1334 <tt>i32</tt>.</td>
1335 </tr>
1336 <tr class="layout">
1337 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1338 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1339 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1340 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1341</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1342</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1343
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1344<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1345<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1346<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1347
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1348<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1349
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1350<p>A vector type is a simple derived type that represents a vector
1351of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1352are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1353A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1354elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1355of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1356considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1357
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1358<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1359
1360<pre>
1361 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1362</pre>
1363
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1364<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1365be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1366
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1367<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1368
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1369<table class="layout">
1370 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1371 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1372 <td class="left">Vector of 4 32-bit integer values.</td>
1373 </tr>
1374 <tr class="layout">
1375 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1376 <td class="left">Vector of 8 32-bit floating-point values.</td>
1377 </tr>
1378 <tr class="layout">
1379 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1380 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1381 </tr>
1382</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1383</div>
1384
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1385<!-- _______________________________________________________________________ -->
1386<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1387<div class="doc_text">
1388
1389<h5>Overview:</h5>
1390
1391<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1392corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1393In LLVM, opaque types can eventually be resolved to any type (not just a
1394structure type).</p>
1395
1396<h5>Syntax:</h5>
1397
1398<pre>
1399 opaque
1400</pre>
1401
1402<h5>Examples:</h5>
1403
1404<table class="layout">
1405 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1406 <td class="left"><tt>opaque</tt></td>
1407 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1408 </tr>
1409</table>
1410</div>
1411
1412
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1413<!-- *********************************************************************** -->
1414<div class="doc_section"> <a name="constants">Constants</a> </div>
1415<!-- *********************************************************************** -->
1416
1417<div class="doc_text">
1418
1419<p>LLVM has several different basic types of constants. This section describes
1420them all and their syntax.</p>
1421
1422</div>
1423
1424<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1425<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1426
1427<div class="doc_text">
1428
1429<dl>
1430 <dt><b>Boolean constants</b></dt>
1431
1432 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1433 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1434 </dd>
1435
1436 <dt><b>Integer constants</b></dt>
1437
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1438 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1439 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1440 integer types.
1441 </dd>
1442
1443 <dt><b>Floating point constants</b></dt>
1444
1445 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1446 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1447 notation (see below). Floating point constants must have a <a
1448 href="#t_floating">floating point</a> type. </dd>
1449
1450 <dt><b>Null pointer constants</b></dt>
1451
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1452 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1453 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1454
1455</dl>
1456
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1457<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1458of floating point constants. For example, the form '<tt>double
14590x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14604.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1461(and the only time that they are generated by the disassembler) is when a
1462floating point constant must be emitted but it cannot be represented as a
1463decimal floating point number. For example, NaN's, infinities, and other
1464special values are represented in their IEEE hexadecimal format so that
1465assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1466
1467</div>
1468
1469<!-- ======================================================================= -->
1470<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1471</div>
1472
1473<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1474<p>Aggregate constants arise from aggregation of simple constants
1475and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1476
1477<dl>
1478 <dt><b>Structure constants</b></dt>
1479
1480 <dd>Structure constants are represented with notation similar to structure
1481 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1482 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1483 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]1484 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1485 types of elements must match those specified by the type.
1486 </dd>
1487
1488 <dt><b>Array constants</b></dt>
1489
1490 <dd>Array constants are represented with notation similar to array type
1491 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1492 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1493 constants must have <a href="#t_array">array type</a>, and the number and
1494 types of elements must match those specified by the type.
1495 </dd>
1496
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1497 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1498
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1499 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1500 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1501 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]1502 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1503 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1504 match those specified by the type.
1505 </dd>
1506
1507 <dt><b>Zero initialization</b></dt>
1508
1509 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1510 value to zero of <em>any</em> type, including scalar and aggregate types.
1511 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]1512 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1513 initializers.
1514 </dd>
1515</dl>
1516
1517</div>
1518
1519<!-- ======================================================================= -->
1520<div class="doc_subsection">
1521 <a name="globalconstants">Global Variable and Function Addresses</a>
1522</div>
1523
1524<div class="doc_text">
1525
1526<p>The addresses of <a href="#globalvars">global variables</a> and <a
1527href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1528constants. These constants are explicitly referenced when the <a
1529href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1530href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1531file:</p>
1532
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1533<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1534<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1535@X = global i32 17
1536@Y = global i32 42
1537@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1538</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1539</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1540
1541</div>
1542
1543<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1544<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1545<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1546 <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]1547 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1548 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1549
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1550 <p>Undefined values indicate to the compiler that the program is well defined
1551 no matter what value is used, giving the compiler more freedom to optimize.
1552 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1553</div>
1554
1555<!-- ======================================================================= -->
1556<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1557</div>
1558
1559<div class="doc_text">
1560
1561<p>Constant expressions are used to allow expressions involving other constants
1562to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1563href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1564that does not have side effects (e.g. load and call are not supported). The
1565following is the syntax for constant expressions:</p>
1566
1567<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1568 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1569 <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]1570 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1571
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1572 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1573 <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]1574 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]1575
1576 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1577 <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]1578 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]1579
1580 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1581 <dd>Truncate a floating point constant to another floating point type. The
1582 size of CST must be larger than the size of TYPE. Both types must be
1583 floating point.</dd>
1584
1585 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1586 <dd>Floating point extend a constant to another type. The size of CST must be
1587 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1588
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1589 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1590 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1591 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1592 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1593 of the same number of elements. If the value won't fit in the integer type,
1594 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1595
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1596 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1597 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1598 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1599 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1600 of the same number of elements. If the value won't fit in the integer type,
1601 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1602
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1603 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1604 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1605 constant. TYPE must be a scalar or vector floating point type. CST must be of
1606 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1607 of the same number of elements. If the value won't fit in the floating point
1608 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1609
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1610 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1611 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1612 constant. TYPE must be a scalar or vector floating point type. CST must be of
1613 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1614 of the same number of elements. If the value won't fit in the floating point
1615 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1616
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1617 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1618 <dd>Convert a pointer typed constant to the corresponding integer constant
1619 TYPE must be an integer type. CST must be of pointer type. The CST value is
1620 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1621
1622 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1623 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1624 pointer type. CST must be of integer type. The CST value is zero extended,
1625 truncated, or unchanged to make it fit in a pointer size. This one is
1626 <i>really</i> dangerous!</dd>
1627
1628 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1629 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1630 identical (same number of bits). The conversion is done as if the CST value
1631 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]1632 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1633 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]1634 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1635 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1636
1637 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1638
1639 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1640 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1641 instruction, the index list may have zero or more indexes, which are required
1642 to make sense for the type of "CSTPTR".</dd>
1643
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1644 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1645
1646 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1647 constants.</dd>
1648
1649 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1650 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1651
1652 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1653 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1654
1655 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1656
1657 <dd>Perform the <a href="#i_extractelement">extractelement
1658 operation</a> on constants.
1659
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1660 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1661
1662 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1663 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1664
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1665
1666 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1667
1668 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1669 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1670
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1671 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1672
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1673 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1674 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1675 binary</a> operations. The constraints on operands are the same as those for
1676 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1677 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1678</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1679</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1680
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1681<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1682<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1683<!-- *********************************************************************** -->
1684
1685<!-- ======================================================================= -->
1686<div class="doc_subsection">
1687<a name="inlineasm">Inline Assembler Expressions</a>
1688</div>
1689
1690<div class="doc_text">
1691
1692<p>
1693LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1694Module-Level Inline Assembly</a>) through the use of a special value. This
1695value represents the inline assembler as a string (containing the instructions
1696to emit), a list of operand constraints (stored as a string), and a flag that
1697indicates whether or not the inline asm expression has side effects. An example
1698inline assembler expression is:
1699</p>
1700
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1701<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1702<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1703i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1704</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1705</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1706
1707<p>
1708Inline assembler expressions may <b>only</b> be used as the callee operand of
1709a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1710</p>
1711
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1712<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1713<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1714%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]1715</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1716</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1717
1718<p>
1719Inline asms with side effects not visible in the constraint list must be marked
1720as having side effects. This is done through the use of the
1721'<tt>sideeffect</tt>' keyword, like so:
1722</p>
1723
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1724<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1725<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1726call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1727</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1728</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1729
1730<p>TODO: The format of the asm and constraints string still need to be
1731documented here. Constraints on what can be done (e.g. duplication, moving, etc
1732need to be documented).
1733</p>
1734
1735</div>
1736
1737<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1738<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1739<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1740
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1741<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1742
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743<p>The LLVM instruction set consists of several different
1744classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1745instructions</a>, <a href="#binaryops">binary instructions</a>,
1746<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1747 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1748instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1749
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1751
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1753<div class="doc_subsection"> <a name="terminators">Terminator
1754Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1755
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1756<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1757
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758<p>As mentioned <a href="#functionstructure">previously</a>, every
1759basic block in a program ends with a "Terminator" instruction, which
1760indicates which block should be executed after the current block is
1761finished. These terminator instructions typically yield a '<tt>void</tt>'
1762value: they produce control flow, not values (the one exception being
1763the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1764<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1765 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1766instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1767the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1768 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1769 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1770
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1771</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1774<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1775Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1776<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1777<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1778<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]1779 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1782<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1783value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1784<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1785returns a value and then causes control flow, and one that just causes
1786control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1787<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1788<p>The '<tt>ret</tt>' instruction may return any '<a
1789 href="#t_firstclass">first class</a>' type. Notice that a function is
1790not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1791instruction inside of the function that returns a value that does not
1792match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1793<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1794<p>When the '<tt>ret</tt>' instruction is executed, control flow
1795returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1796 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1797the instruction after the call. If the caller was an "<a
1798 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1799at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1800returns a value, that value shall set the call or invoke instruction's
1801return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1802<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1803<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1804 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1806</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1807<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1808<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1809<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1810<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1811<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]1812</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1813<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1814<p>The '<tt>br</tt>' instruction is used to cause control flow to
1815transfer to a different basic block in the current function. There are
1816two forms of this instruction, corresponding to a conditional branch
1817and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1819<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1820single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1821unconditional form of the '<tt>br</tt>' instruction takes a single
1822'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1823<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1824<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1825argument is evaluated. If the value is <tt>true</tt>, control flows
1826to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1827control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1829<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]1830 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]1831</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1833<div class="doc_subsubsection">
1834 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1835</div>
1836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1837<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1838<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1839
1840<pre>
1841 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1842</pre>
1843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1844<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1845
1846<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1847several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1848instruction, allowing a branch to occur to one of many possible
1849destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1850
1851
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1852<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1853
1854<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1855comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1856an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1857table is not allowed to contain duplicate constant entries.</p>
1858
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1859<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1860
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<p>The <tt>switch</tt> instruction specifies a table of values and
1862destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1863table is searched for the given value. If the value is found, control flow is
1864transfered to the corresponding destination; otherwise, control flow is
1865transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1866
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1867<h5>Implementation:</h5>
1868
1869<p>Depending on properties of the target machine and the particular
1870<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1871ways. For example, it could be generated as a series of chained conditional
1872branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1873
1874<h5>Example:</h5>
1875
1876<pre>
1877 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1878 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1879 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1880
1881 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1882 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1883
1884 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1885 switch i32 %val, label %otherwise [ i32 0, label %onzero
1886 i32 1, label %onone
1887 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1888</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1889</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1890
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1891<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1892<div class="doc_subsubsection">
1893 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1894</div>
1895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1896<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1898<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1899
1900<pre>
1901 &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]1902 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1903</pre>
1904
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1905<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1906
1907<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1908function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1909'<tt>normal</tt>' label or the
1910'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1911"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1912"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1913href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1914continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1917
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1918<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1919
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1920<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1921 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1922 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1923 convention</a> the call should use. If none is specified, the call defaults
1924 to using C calling conventions.
1925 </li>
1926 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1927 function value being invoked. In most cases, this is a direct function
1928 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1929 an arbitrary pointer to function value.
1930 </li>
1931
1932 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1933 function to be invoked. </li>
1934
1935 <li>'<tt>function args</tt>': argument list whose types match the function
1936 signature argument types. If the function signature indicates the function
1937 accepts a variable number of arguments, the extra arguments can be
1938 specified. </li>
1939
1940 <li>'<tt>normal label</tt>': the label reached when the called function
1941 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1942
1943 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1944 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1946</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1947
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1948<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1950<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1951href="#i_call">call</a></tt>' instruction in most regards. The primary
1952difference is that it establishes an association with a label, which is used by
1953the runtime library to unwind the stack.</p>
1954
1955<p>This instruction is used in languages with destructors to ensure that proper
1956cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1957exception. Additionally, this is important for implementation of
1958'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1960<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1961<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1962 %retval = invoke i32 %Test(i32 15) to label %Continue
1963 unwind label %TestCleanup <i>; {i32}:retval set</i>
1964 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1965 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1966</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1967</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1968
1969
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1970<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1971
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1972<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1973Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1974
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1975<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1976
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1977<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1978<pre>
1979 unwind
1980</pre>
1981
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1982<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1983
1984<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1985at the first callee in the dynamic call stack which used an <a
1986href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1987primarily used to implement exception handling.</p>
1988
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1989<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1990
1991<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1992immediately halt. The dynamic call stack is then searched for the first <a
1993href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1994execution continues at the "exceptional" destination block specified by the
1995<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1996dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1997</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1998
1999<!-- _______________________________________________________________________ -->
2000
2001<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2002Instruction</a> </div>
2003
2004<div class="doc_text">
2005
2006<h5>Syntax:</h5>
2007<pre>
2008 unreachable
2009</pre>
2010
2011<h5>Overview:</h5>
2012
2013<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2014instruction is used to inform the optimizer that a particular portion of the
2015code is not reachable. This can be used to indicate that the code after a
2016no-return function cannot be reached, and other facts.</p>
2017
2018<h5>Semantics:</h5>
2019
2020<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2021</div>
2022
2023
2024
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2025<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2026<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2027<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2028<p>Binary operators are used to do most of the computation in a
2029program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2030produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2031multiple 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]2032The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2033necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2034<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2035</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2036<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2037<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2038Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2039<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2041<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]2042</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2044<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2045<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2046<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2047 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2048 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]2049Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2050<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2051<p>The value produced is the integer or floating point sum of the two
2052operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2053<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2054<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]2055</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2056</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2057<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2058<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2059Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2060<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2061<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2062<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]2063</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2064<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2065<p>The '<tt>sub</tt>' instruction returns the difference of its two
2066operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2067<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2068instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2070<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2071 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2072values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2073This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2074Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2076<p>The value produced is the integer or floating point difference of
2077the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2078<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2079<pre>
2080 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2081 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2082</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2083</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2084<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2085<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2086Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2087<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2088<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2089<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]2090</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2091<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2092<p>The '<tt>mul</tt>' instruction returns the product of its two
2093operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2095<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2096 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2097values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2098This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2099Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2100<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2101<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2102two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2103<p>Because the operands are the same width, the result of an integer
2104multiplication is the same whether the operands should be deemed unsigned or
2105signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2106<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2107<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]2108</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2109</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2110<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2111<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2112</a></div>
2113<div class="doc_text">
2114<h5>Syntax:</h5>
2115<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2116</pre>
2117<h5>Overview:</h5>
2118<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2119operands.</p>
2120<h5>Arguments:</h5>
2121<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2122<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2123types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2124of the values in which case the elements must be integers.</p>
2125<h5>Semantics:</h5>
2126<p>The value produced is the unsigned integer quotient of the two operands. This
2127instruction always performs an unsigned division operation, regardless of
2128whether the arguments are unsigned or not.</p>
2129<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2130<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]2131</pre>
2132</div>
2133<!-- _______________________________________________________________________ -->
2134<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2135</a> </div>
2136<div class="doc_text">
2137<h5>Syntax:</h5>
2138<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2139</pre>
2140<h5>Overview:</h5>
2141<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2142operands.</p>
2143<h5>Arguments:</h5>
2144<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2145<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2146types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2147of the values in which case the elements must be integers.</p>
2148<h5>Semantics:</h5>
2149<p>The value produced is the signed integer quotient of the two operands. This
2150instruction always performs a signed division operation, regardless of whether
2151the arguments are signed or not.</p>
2152<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2153<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]2154</pre>
2155</div>
2156<!-- _______________________________________________________________________ -->
2157<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2158Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2159<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2160<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2161<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]2162</pre>
2163<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2164<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2165operands.</p>
2166<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2167<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2168<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2169identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2170versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2171<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2172<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2173<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2174<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]2175</pre>
2176</div>
2177<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2178<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2179</div>
2180<div class="doc_text">
2181<h5>Syntax:</h5>
2182<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2183</pre>
2184<h5>Overview:</h5>
2185<p>The '<tt>urem</tt>' instruction returns the remainder from the
2186unsigned division of its two arguments.</p>
2187<h5>Arguments:</h5>
2188<p>The two arguments to the '<tt>urem</tt>' instruction must be
2189<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2190types. This instruction can also take <a href="#t_vector">vector</a> versions
2191of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2192<h5>Semantics:</h5>
2193<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2194This instruction always performs an unsigned division to get the remainder,
2195regardless of whether the arguments are unsigned or not.</p>
2196<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2197<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]2198</pre>
2199
2200</div>
2201<!-- _______________________________________________________________________ -->
2202<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2203Instruction</a> </div>
2204<div class="doc_text">
2205<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2206<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]2207</pre>
2208<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2209<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2210signed division of its two operands. This instruction can also take
2211<a href="#t_vector">vector</a> versions of the values in which case
2212the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2213
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2214<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2215<p>The two arguments to the '<tt>srem</tt>' instruction must be
2216<a href="#t_integer">integer</a> values. Both arguments must have identical
2217types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2218<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2219<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2220has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2221operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2222a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2223 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2224Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2225please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2226Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2227<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2228<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]2229</pre>
2230
2231</div>
2232<!-- _______________________________________________________________________ -->
2233<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2234Instruction</a> </div>
2235<div class="doc_text">
2236<h5>Syntax:</h5>
2237<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2238</pre>
2239<h5>Overview:</h5>
2240<p>The '<tt>frem</tt>' instruction returns the remainder from the
2241division of its two operands.</p>
2242<h5>Arguments:</h5>
2243<p>The two arguments to the '<tt>frem</tt>' instruction must be
2244<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2245identical types. This instruction can also take <a href="#t_vector">vector</a>
2246versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2247<h5>Semantics:</h5>
2248<p>This instruction returns the <i>remainder</i> of a division.</p>
2249<h5>Example:</h5>
2250<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]2251</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2252</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2253
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2254<!-- ======================================================================= -->
2255<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2256Operations</a> </div>
2257<div class="doc_text">
2258<p>Bitwise binary operators are used to do various forms of
2259bit-twiddling in a program. They are generally very efficient
2260instructions and can commonly be strength reduced from other
2261instructions. They require two operands, execute an operation on them,
2262and produce a single value. The resulting value of the bitwise binary
2263operators is always the same type as its first operand.</p>
2264</div>
2265
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2266<!-- _______________________________________________________________________ -->
2267<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2268Instruction</a> </div>
2269<div class="doc_text">
2270<h5>Syntax:</h5>
2271<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2272</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2273
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2274<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2275
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2276<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2277the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2278
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2279<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2280
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2281<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2282 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2283
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2284<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2285
2286<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2287<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2288of bits in <tt>var1</tt>, the result is undefined.</p>
2289
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2290<h5>Example:</h5><pre>
2291 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2292 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2293 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2294 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2295</pre>
2296</div>
2297<!-- _______________________________________________________________________ -->
2298<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2299Instruction</a> </div>
2300<div class="doc_text">
2301<h5>Syntax:</h5>
2302<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2303</pre>
2304
2305<h5>Overview:</h5>
2306<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2307operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2308
2309<h5>Arguments:</h5>
2310<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2311<a href="#t_integer">integer</a> type.</p>
2312
2313<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2314
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2315<p>This instruction always performs a logical shift right operation. The most
2316significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2317shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2318the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2319
2320<h5>Example:</h5>
2321<pre>
2322 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2323 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2324 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2325 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2326 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2327</pre>
2328</div>
2329
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2330<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2331<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2332Instruction</a> </div>
2333<div class="doc_text">
2334
2335<h5>Syntax:</h5>
2336<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2337</pre>
2338
2339<h5>Overview:</h5>
2340<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2341operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2342
2343<h5>Arguments:</h5>
2344<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2345<a href="#t_integer">integer</a> type.</p>
2346
2347<h5>Semantics:</h5>
2348<p>This instruction always performs an arithmetic shift right operation,
2349The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2350of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2351larger than the number of bits in <tt>var1</tt>, the result is undefined.
2352</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2353
2354<h5>Example:</h5>
2355<pre>
2356 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2357 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2358 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2359 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2360 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2361</pre>
2362</div>
2363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2365<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2366Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2367<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2368<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2369<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]2370</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2371<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2372<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2373its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2374<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2375<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2376 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2377identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2378<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2379<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2380<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2381<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2382<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2383 <tbody>
2384 <tr>
2385 <td>In0</td>
2386 <td>In1</td>
2387 <td>Out</td>
2388 </tr>
2389 <tr>
2390 <td>0</td>
2391 <td>0</td>
2392 <td>0</td>
2393 </tr>
2394 <tr>
2395 <td>0</td>
2396 <td>1</td>
2397 <td>0</td>
2398 </tr>
2399 <tr>
2400 <td>1</td>
2401 <td>0</td>
2402 <td>0</td>
2403 </tr>
2404 <tr>
2405 <td>1</td>
2406 <td>1</td>
2407 <td>1</td>
2408 </tr>
2409 </tbody>
2410</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2411</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2412<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2413<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2414 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2415 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2416</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2417</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2418<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2419<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2420<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2421<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2422<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]2423</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2424<h5>Overview:</h5>
2425<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2426or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2427<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2428<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2429 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2430identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2431<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2432<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2433<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2434<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2435<table border="1" cellspacing="0" cellpadding="4">
2436 <tbody>
2437 <tr>
2438 <td>In0</td>
2439 <td>In1</td>
2440 <td>Out</td>
2441 </tr>
2442 <tr>
2443 <td>0</td>
2444 <td>0</td>
2445 <td>0</td>
2446 </tr>
2447 <tr>
2448 <td>0</td>
2449 <td>1</td>
2450 <td>1</td>
2451 </tr>
2452 <tr>
2453 <td>1</td>
2454 <td>0</td>
2455 <td>1</td>
2456 </tr>
2457 <tr>
2458 <td>1</td>
2459 <td>1</td>
2460 <td>1</td>
2461 </tr>
2462 </tbody>
2463</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2464</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2465<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2466<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2467 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2468 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2469</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2470</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2471<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2472<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2473Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2474<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2475<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2476<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]2477</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2478<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2479<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2480or of its two operands. The <tt>xor</tt> is used to implement the
2481"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2482<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2483<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2484 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2485identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2486<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2487<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2488<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2489<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2490<table border="1" cellspacing="0" cellpadding="4">
2491 <tbody>
2492 <tr>
2493 <td>In0</td>
2494 <td>In1</td>
2495 <td>Out</td>
2496 </tr>
2497 <tr>
2498 <td>0</td>
2499 <td>0</td>
2500 <td>0</td>
2501 </tr>
2502 <tr>
2503 <td>0</td>
2504 <td>1</td>
2505 <td>1</td>
2506 </tr>
2507 <tr>
2508 <td>1</td>
2509 <td>0</td>
2510 <td>1</td>
2511 </tr>
2512 <tr>
2513 <td>1</td>
2514 <td>1</td>
2515 <td>0</td>
2516 </tr>
2517 </tbody>
2518</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2519</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2520<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2521<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2522<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2523 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2524 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2525 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2526</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2527</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2529<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2530<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2531 <a name="vectorops">Vector Operations</a>
2532</div>
2533
2534<div class="doc_text">
2535
2536<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2537target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2538vector-specific operations needed to process vectors effectively. While LLVM
2539does directly support these vector operations, many sophisticated algorithms
2540will want to use target-specific intrinsics to take full advantage of a specific
2541target.</p>
2542
2543</div>
2544
2545<!-- _______________________________________________________________________ -->
2546<div class="doc_subsubsection">
2547 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2548</div>
2549
2550<div class="doc_text">
2551
2552<h5>Syntax:</h5>
2553
2554<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2555 &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]2556</pre>
2557
2558<h5>Overview:</h5>
2559
2560<p>
2561The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2562element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2563</p>
2564
2565
2566<h5>Arguments:</h5>
2567
2568<p>
2569The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2570value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2571an index indicating the position from which to extract the element.
2572The index may be a variable.</p>
2573
2574<h5>Semantics:</h5>
2575
2576<p>
2577The result is a scalar of the same type as the element type of
2578<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2579<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2580results are undefined.
2581</p>
2582
2583<h5>Example:</h5>
2584
2585<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2586 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2587</pre>
2588</div>
2589
2590
2591<!-- _______________________________________________________________________ -->
2592<div class="doc_subsubsection">
2593 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2594</div>
2595
2596<div class="doc_text">
2597
2598<h5>Syntax:</h5>
2599
2600<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2601 &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]2602</pre>
2603
2604<h5>Overview:</h5>
2605
2606<p>
2607The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2608element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2609</p>
2610
2611
2612<h5>Arguments:</h5>
2613
2614<p>
2615The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2616value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2617scalar value whose type must equal the element type of the first
2618operand. The third operand is an index indicating the position at
2619which to insert the value. The index may be a variable.</p>
2620
2621<h5>Semantics:</h5>
2622
2623<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2624The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2625element values are those of <tt>val</tt> except at position
2626<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2627exceeds the length of <tt>val</tt>, the results are undefined.
2628</p>
2629
2630<h5>Example:</h5>
2631
2632<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2633 %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]2634</pre>
2635</div>
2636
2637<!-- _______________________________________________________________________ -->
2638<div class="doc_subsubsection">
2639 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2640</div>
2641
2642<div class="doc_text">
2643
2644<h5>Syntax:</h5>
2645
2646<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2647 &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]2648</pre>
2649
2650<h5>Overview:</h5>
2651
2652<p>
2653The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2654from two input vectors, returning a vector of the same type.
2655</p>
2656
2657<h5>Arguments:</h5>
2658
2659<p>
2660The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2661with types that match each other and types that match the result of the
2662instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2663of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2664</p>
2665
2666<p>
2667The shuffle mask operand is required to be a constant vector with either
2668constant integer or undef values.
2669</p>
2670
2671<h5>Semantics:</h5>
2672
2673<p>
2674The elements of the two input vectors are numbered from left to right across
2675both of the vectors. The shuffle mask operand specifies, for each element of
2676the result vector, which element of the two input registers the result element
2677gets. The element selector may be undef (meaning "don't care") and the second
2678operand may be undef if performing a shuffle from only one vector.
2679</p>
2680
2681<h5>Example:</h5>
2682
2683<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2684 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2685 &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]2686 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2687 &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]2688</pre>
2689</div>
2690
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2691
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2692<!-- ======================================================================= -->
2693<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2694 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2695</div>
2696
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2697<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2698
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2699<p>A key design point of an SSA-based representation is how it
2700represents memory. In LLVM, no memory locations are in SSA form, which
2701makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2702allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2703
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2704</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2706<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2707<div class="doc_subsubsection">
2708 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2709</div>
2710
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2711<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2712
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2713<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2714
2715<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2716 &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]2717</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2718
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2719<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2720
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2721<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2722heap and returns a pointer to it. The object is always allocated in the generic
2723address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2725<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2726
2727<p>The '<tt>malloc</tt>' instruction allocates
2728<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2729bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2730appropriate type to the program. If "NumElements" is specified, it is the
2731number of elements allocated. If an alignment is specified, the value result
2732of the allocation is guaranteed to be aligned to at least that boundary. If
2733not specified, or if zero, the target can choose to align the allocation on any
2734convenient boundary.</p>
2735
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2736<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2738<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2739
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2740<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2741a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2742
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2743<h5>Example:</h5>
2744
2745<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2746 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2747
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2748 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2749 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2750 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2751 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2752 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2753</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2754</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2755
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2756<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2757<div class="doc_subsubsection">
2758 <a name="i_free">'<tt>free</tt>' Instruction</a>
2759</div>
2760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2761<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2762
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2763<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2764
2765<pre>
2766 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2767</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2768
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2769<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2770
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2771<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2772memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2774<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2775
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2776<p>'<tt>value</tt>' shall be a pointer value that points to a value
2777that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2778instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2780<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2781
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2782<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2783after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2784
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2785<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2786
2787<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2788 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2789 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2790</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2791</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2793<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2794<div class="doc_subsubsection">
2795 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2796</div>
2797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2798<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2799
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2800<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2801
2802<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2803 &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]2804</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2806<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2807
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2808<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2809currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2810returns to its caller. The object is always allocated in the generic address
2811space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2813<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2814
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2815<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2816bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2817appropriate type to the program. If "NumElements" is specified, it is the
2818number of elements allocated. If an alignment is specified, the value result
2819of the allocation is guaranteed to be aligned to at least that boundary. If
2820not specified, or if zero, the target can choose to align the allocation on any
2821convenient boundary.</p>
2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2826
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2827<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2828memory is automatically released when the function returns. The '<tt>alloca</tt>'
2829instruction is commonly used to represent automatic variables that must
2830have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2831 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]2832instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2835
2836<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2837 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2838 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2839 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2840 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2841</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2842</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2845<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2846Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2847<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2848<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2849<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]2850<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2851<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2852<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2853<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2854address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2855 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2856marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2857the number or order of execution of this <tt>load</tt> with other
2858volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2859instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2860<p>
2861The optional "align" argument specifies the alignment of the operation
2862(that is, the alignment of the memory address). A value of 0 or an
2863omitted "align" argument means that the operation has the preferential
2864alignment for the target. It is the responsibility of the code emitter
2865to ensure that the alignment information is correct. Overestimating
2866the alignment results in an undefined behavior. Underestimating the
2867alignment may produce less efficient code. An alignment of 1 is always
2868safe.
2869</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2870<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2871<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2872<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2873<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2874 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2875 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2876 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2877</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2878</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2879<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2880<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2881Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2882<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2883<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2884<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2885 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]2886</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2887<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2888<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2889<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2890<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2891to 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]2892operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2893operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2894optimizer is not allowed to modify the number or order of execution of
2895this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2896 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2897<p>
2898The optional "align" argument specifies the alignment of the operation
2899(that is, the alignment of the memory address). A value of 0 or an
2900omitted "align" argument means that the operation has the preferential
2901alignment for the target. It is the responsibility of the code emitter
2902to ensure that the alignment information is correct. Overestimating
2903the alignment results in an undefined behavior. Underestimating the
2904alignment may produce less efficient code. An alignment of 1 is always
2905safe.
2906</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2907<h5>Semantics:</h5>
2908<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2909at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2910<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2911<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2912 store i32 3, i32* %ptr <i>; yields {void}</i>
2913 %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]2914</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2915</div>
2916
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2917<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2918<div class="doc_subsubsection">
2919 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2920</div>
2921
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2922<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2923<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2924<pre>
2925 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2926</pre>
2927
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2928<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2929
2930<p>
2931The '<tt>getelementptr</tt>' instruction is used to get the address of a
2932subelement of an aggregate data structure.</p>
2933
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2934<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2935
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2936<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2937elements of the aggregate object to index to. The actual types of the arguments
2938provided depend on the type of the first pointer argument. The
2939'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2940levels 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]2941structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2942into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2943be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2944
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2945<p>For example, let's consider a C code fragment and how it gets
2946compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2947
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2948<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2949<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2950struct RT {
2951 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2952 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2953 char C;
2954};
2955struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2956 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2957 double Y;
2958 struct RT Z;
2959};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2960
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2961int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2962 return &amp;s[1].Z.B[5][13];
2963}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2964</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2965</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2966
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2967<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2968
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2969<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2970<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2971%RT = type { i8 , [10 x [20 x i32]], i8 }
2972%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2973
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2974define i32* %foo(%ST* %s) {
2975entry:
2976 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2977 ret i32* %reg
2978}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2979</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2980</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2981
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2982<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2983
2984<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2985on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2986and <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]2987<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]2988to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2989<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2990
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2991<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]2992type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2993}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2994the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2995i8 }</tt>' type, another structure. The third index indexes into the second
2996element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2997array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2998'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2999to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3000
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3001<p>Note that it is perfectly legal to index partially through a
3002structure, returning a pointer to an inner element. Because of this,
3003the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3004
3005<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3006 define i32* %foo(%ST* %s) {
3007 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3008 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3009 %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]3010 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3011 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3012 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3013 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3014</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3015
3016<p>Note that it is undefined to access an array out of bounds: array and
3017pointer indexes must always be within the defined bounds of the array type.
3018The one exception for this rules is zero length arrays. These arrays are
3019defined to be accessible as variable length arrays, which requires access
3020beyond the zero'th element.</p>
3021
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3022<p>The getelementptr instruction is often confusing. For some more insight
3023into how it works, see <a href="GetElementPtr.html">the getelementptr
3024FAQ</a>.</p>
3025
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3026<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3027
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3028<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3029 <i>; yields [12 x i8]*:aptr</i>
3030 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3031</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3032</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3033
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3034<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3035<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3036</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3037<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3038<p>The instructions in this category are the conversion instructions (casting)
3039which all take a single operand and a type. They perform various bit conversions
3040on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3041</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3042
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3043<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3044<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3045 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3046</div>
3047<div class="doc_text">
3048
3049<h5>Syntax:</h5>
3050<pre>
3051 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3052</pre>
3053
3054<h5>Overview:</h5>
3055<p>
3056The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3057</p>
3058
3059<h5>Arguments:</h5>
3060<p>
3061The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3062be 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]3063and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3064type. The bit size of <tt>value</tt> must be larger than the bit size of
3065<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3066
3067<h5>Semantics:</h5>
3068<p>
3069The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3070and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3071larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3072It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3073
3074<h5>Example:</h5>
3075<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3076 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3077 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3078 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3079</pre>
3080</div>
3081
3082<!-- _______________________________________________________________________ -->
3083<div class="doc_subsubsection">
3084 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3085</div>
3086<div class="doc_text">
3087
3088<h5>Syntax:</h5>
3089<pre>
3090 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3091</pre>
3092
3093<h5>Overview:</h5>
3094<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3095<tt>ty2</tt>.</p>
3096
3097
3098<h5>Arguments:</h5>
3099<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]3100<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3101also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3102<tt>value</tt> must be smaller than the bit size of the destination type,
3103<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3104
3105<h5>Semantics:</h5>
3106<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]3107bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3108
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3109<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]3110
3111<h5>Example:</h5>
3112<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3113 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3114 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3115</pre>
3116</div>
3117
3118<!-- _______________________________________________________________________ -->
3119<div class="doc_subsubsection">
3120 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3121</div>
3122<div class="doc_text">
3123
3124<h5>Syntax:</h5>
3125<pre>
3126 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3127</pre>
3128
3129<h5>Overview:</h5>
3130<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3131
3132<h5>Arguments:</h5>
3133<p>
3134The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3135<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3136also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3137<tt>value</tt> must be smaller than the bit size of the destination type,
3138<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3139
3140<h5>Semantics:</h5>
3141<p>
3142The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3143bit (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]3144the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3145
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3146<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]3147
3148<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3149<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3150 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3151 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3152</pre>
3153</div>
3154
3155<!-- _______________________________________________________________________ -->
3156<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3157 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3158</div>
3159
3160<div class="doc_text">
3161
3162<h5>Syntax:</h5>
3163
3164<pre>
3165 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3166</pre>
3167
3168<h5>Overview:</h5>
3169<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3170<tt>ty2</tt>.</p>
3171
3172
3173<h5>Arguments:</h5>
3174<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3175 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3176cast it to. The size of <tt>value</tt> must be larger than the size of
3177<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3178<i>no-op cast</i>.</p>
3179
3180<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3181<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3182<a href="#t_floating">floating point</a> type to a smaller
3183<a href="#t_floating">floating point</a> type. If the value cannot fit within
3184the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3185
3186<h5>Example:</h5>
3187<pre>
3188 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3189 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3190</pre>
3191</div>
3192
3193<!-- _______________________________________________________________________ -->
3194<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3195 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3196</div>
3197<div class="doc_text">
3198
3199<h5>Syntax:</h5>
3200<pre>
3201 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3202</pre>
3203
3204<h5>Overview:</h5>
3205<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3206floating point value.</p>
3207
3208<h5>Arguments:</h5>
3209<p>The '<tt>fpext</tt>' instruction takes a
3210<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3211and a <a href="#t_floating">floating point</a> type to cast it to. The source
3212type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3213
3214<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3215<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3216<a href="#t_floating">floating point</a> type to a larger
3217<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3218used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3219<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]3220
3221<h5>Example:</h5>
3222<pre>
3223 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3224 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3225</pre>
3226</div>
3227
3228<!-- _______________________________________________________________________ -->
3229<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3230 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3231</div>
3232<div class="doc_text">
3233
3234<h5>Syntax:</h5>
3235<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3236 &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]3237</pre>
3238
3239<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3240<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3241unsigned integer equivalent of type <tt>ty2</tt>.
3242</p>
3243
3244<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3245<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3246scalar or vector <a href="#t_floating">floating point</a> value, and a type
3247to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3248type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3249vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3250
3251<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3252<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3253<a href="#t_floating">floating point</a> operand into the nearest (rounding
3254towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3255the results are undefined.</p>
3256
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3257<h5>Example:</h5>
3258<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3259 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3260 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3261 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3262</pre>
3263</div>
3264
3265<!-- _______________________________________________________________________ -->
3266<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3267 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3268</div>
3269<div class="doc_text">
3270
3271<h5>Syntax:</h5>
3272<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3273 &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]3274</pre>
3275
3276<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3277<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3278<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]3279</p>
3280
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3281<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3282<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3283scalar or vector <a href="#t_floating">floating point</a> value, and a type
3284to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3285type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3286vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3287
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3288<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3289<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3290<a href="#t_floating">floating point</a> operand into the nearest (rounding
3291towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3292the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3293
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3294<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3295<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3296 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3297 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3298 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3299</pre>
3300</div>
3301
3302<!-- _______________________________________________________________________ -->
3303<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3304 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3305</div>
3306<div class="doc_text">
3307
3308<h5>Syntax:</h5>
3309<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3310 &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]3311</pre>
3312
3313<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3314<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3315integer and converts that value to the <tt>ty2</tt> type.</p>
3316
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3317<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3318<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3319scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3320to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3321type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3322floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3323
3324<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3325<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3326integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3327the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3328
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3329<h5>Example:</h5>
3330<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3331 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3332 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3333</pre>
3334</div>
3335
3336<!-- _______________________________________________________________________ -->
3337<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3338 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3339</div>
3340<div class="doc_text">
3341
3342<h5>Syntax:</h5>
3343<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3344 &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]3345</pre>
3346
3347<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3348<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3349integer and converts that value to the <tt>ty2</tt> type.</p>
3350
3351<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3352<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3353scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3354to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3355type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3356floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3357
3358<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3359<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3360integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3361the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3362
3363<h5>Example:</h5>
3364<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3365 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3366 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3367</pre>
3368</div>
3369
3370<!-- _______________________________________________________________________ -->
3371<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3372 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3373</div>
3374<div class="doc_text">
3375
3376<h5>Syntax:</h5>
3377<pre>
3378 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3379</pre>
3380
3381<h5>Overview:</h5>
3382<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3383the integer type <tt>ty2</tt>.</p>
3384
3385<h5>Arguments:</h5>
3386<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3387must 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]3388<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3389
3390<h5>Semantics:</h5>
3391<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3392<tt>ty2</tt> by interpreting the pointer value as an integer and either
3393truncating or zero extending that value to the size of the integer type. If
3394<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3395<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]3396are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3397change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3398
3399<h5>Example:</h5>
3400<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3401 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3402 %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]3403</pre>
3404</div>
3405
3406<!-- _______________________________________________________________________ -->
3407<div class="doc_subsubsection">
3408 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3409</div>
3410<div class="doc_text">
3411
3412<h5>Syntax:</h5>
3413<pre>
3414 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3415</pre>
3416
3417<h5>Overview:</h5>
3418<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3419a pointer type, <tt>ty2</tt>.</p>
3420
3421<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3422<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3423value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3424<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3425
3426<h5>Semantics:</h5>
3427<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3428<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3429the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3430size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3431the size of a pointer then a zero extension is done. If they are the same size,
3432nothing is done (<i>no-op cast</i>).</p>
3433
3434<h5>Example:</h5>
3435<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3436 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3437 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3438 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3439</pre>
3440</div>
3441
3442<!-- _______________________________________________________________________ -->
3443<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3444 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3445</div>
3446<div class="doc_text">
3447
3448<h5>Syntax:</h5>
3449<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3450 &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]3451</pre>
3452
3453<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3454<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3455<tt>ty2</tt> without changing any bits.</p>
3456
3457<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3458<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3459a first class value, and a type to cast it to, which must also be a <a
3460 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3461and the destination type, <tt>ty2</tt>, must be identical. If the source
3462type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3463
3464<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3465<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3466<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3467this conversion. The conversion is done as if the <tt>value</tt> had been
3468stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3469converted to other pointer types with this instruction. To convert pointers to
3470other types, use the <a href="#i_inttoptr">inttoptr</a> or
3471<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3472
3473<h5>Example:</h5>
3474<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3475 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3476 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3477 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3478</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3479</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3480
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3481<!-- ======================================================================= -->
3482<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3483<div class="doc_text">
3484<p>The instructions in this category are the "miscellaneous"
3485instructions, which defy better classification.</p>
3486</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3487
3488<!-- _______________________________________________________________________ -->
3489<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3490</div>
3491<div class="doc_text">
3492<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3493<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]3494</pre>
3495<h5>Overview:</h5>
3496<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3497of its two integer operands.</p>
3498<h5>Arguments:</h5>
3499<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3500the condition code indicating the kind of comparison to perform. It is not
3501a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3502<ol>
3503 <li><tt>eq</tt>: equal</li>
3504 <li><tt>ne</tt>: not equal </li>
3505 <li><tt>ugt</tt>: unsigned greater than</li>
3506 <li><tt>uge</tt>: unsigned greater or equal</li>
3507 <li><tt>ult</tt>: unsigned less than</li>
3508 <li><tt>ule</tt>: unsigned less or equal</li>
3509 <li><tt>sgt</tt>: signed greater than</li>
3510 <li><tt>sge</tt>: signed greater or equal</li>
3511 <li><tt>slt</tt>: signed less than</li>
3512 <li><tt>sle</tt>: signed less or equal</li>
3513</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3514<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3515<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3516<h5>Semantics:</h5>
3517<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3518the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3519yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3520<ol>
3521 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3522 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3523 </li>
3524 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3525 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3526 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3527 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3528 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3529 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3530 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3531 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3532 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3533 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3534 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3535 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3536 <li><tt>sge</tt>: interprets the operands as signed values and yields
3537 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3538 <li><tt>slt</tt>: interprets the operands as signed values and yields
3539 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3540 <li><tt>sle</tt>: interprets the operands as signed values and yields
3541 <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]3542</ol>
3543<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3544values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3545
3546<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3547<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3548 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3549 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3550 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3551 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3552 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3553</pre>
3554</div>
3555
3556<!-- _______________________________________________________________________ -->
3557<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3558</div>
3559<div class="doc_text">
3560<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3561<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]3562</pre>
3563<h5>Overview:</h5>
3564<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3565of its floating point operands.</p>
3566<h5>Arguments:</h5>
3567<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3568the condition code indicating the kind of comparison to perform. It is not
3569a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3570<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3571 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3572 <li><tt>oeq</tt>: ordered and equal</li>
3573 <li><tt>ogt</tt>: ordered and greater than </li>
3574 <li><tt>oge</tt>: ordered and greater than or equal</li>
3575 <li><tt>olt</tt>: ordered and less than </li>
3576 <li><tt>ole</tt>: ordered and less than or equal</li>
3577 <li><tt>one</tt>: ordered and not equal</li>
3578 <li><tt>ord</tt>: ordered (no nans)</li>
3579 <li><tt>ueq</tt>: unordered or equal</li>
3580 <li><tt>ugt</tt>: unordered or greater than </li>
3581 <li><tt>uge</tt>: unordered or greater than or equal</li>
3582 <li><tt>ult</tt>: unordered or less than </li>
3583 <li><tt>ule</tt>: unordered or less than or equal</li>
3584 <li><tt>une</tt>: unordered or not equal</li>
3585 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3586 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3587</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3588<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3589<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3590<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3591<a href="#t_floating">floating point</a> typed. They must have identical
3592types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3593<h5>Semantics:</h5>
3594<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3595the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3596yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3597<ol>
3598 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3599 <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]3600 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3601 <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]3602 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3603 <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]3604 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3605 <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]3606 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3607 <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]3608 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3609 <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]3610 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3611 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3612 <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]3613 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3614 <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]3615 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3616 <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]3617 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3618 <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]3619 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3620 <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]3621 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3622 <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]3623 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3624 <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]3625 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3626</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3627
3628<h5>Example:</h5>
3629<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3630 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3631 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3632 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3633</pre>
3634</div>
3635
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3636<!-- _______________________________________________________________________ -->
3637<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3638Instruction</a> </div>
3639<div class="doc_text">
3640<h5>Syntax:</h5>
3641<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3642<h5>Overview:</h5>
3643<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3644the SSA graph representing the function.</p>
3645<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3646<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3647field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3648as arguments, with one pair for each predecessor basic block of the
3649current block. Only values of <a href="#t_firstclass">first class</a>
3650type may be used as the value arguments to the PHI node. Only labels
3651may be used as the label arguments.</p>
3652<p>There must be no non-phi instructions between the start of a basic
3653block and the PHI instructions: i.e. PHI instructions must be first in
3654a basic block.</p>
3655<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3656<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3657specified by the pair corresponding to the predecessor basic block that executed
3658just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3659<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3660<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]3661</div>
3662
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3663<!-- _______________________________________________________________________ -->
3664<div class="doc_subsubsection">
3665 <a name="i_select">'<tt>select</tt>' Instruction</a>
3666</div>
3667
3668<div class="doc_text">
3669
3670<h5>Syntax:</h5>
3671
3672<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3673 &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]3674</pre>
3675
3676<h5>Overview:</h5>
3677
3678<p>
3679The '<tt>select</tt>' instruction is used to choose one value based on a
3680condition, without branching.
3681</p>
3682
3683
3684<h5>Arguments:</h5>
3685
3686<p>
3687The '<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.
3688</p>
3689
3690<h5>Semantics:</h5>
3691
3692<p>
3693If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3694value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3695</p>
3696
3697<h5>Example:</h5>
3698
3699<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3700 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3701</pre>
3702</div>
3703
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3704
3705<!-- _______________________________________________________________________ -->
3706<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3707 <a name="i_call">'<tt>call</tt>' Instruction</a>
3708</div>
3709
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3710<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3711
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3712<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3713<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3714 &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]3715</pre>
3716
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3717<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3718
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3719<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3721<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3722
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3723<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3724
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3725<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3726 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3727 <p>The optional "tail" marker indicates whether the callee function accesses
3728 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3729 function call is eligible for tail call optimization. Note that calls may
3730 be marked "tail" even if they do not occur before a <a
3731 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3732 </li>
3733 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3734 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3735 convention</a> the call should use. If none is specified, the call defaults
3736 to using C calling conventions.
3737 </li>
3738 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3739 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3740 the type of the return value. Functions that return no value are marked
3741 <tt><a href="#t_void">void</a></tt>.</p>
3742 </li>
3743 <li>
3744 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3745 value being invoked. The argument types must match the types implied by
3746 this signature. This type can be omitted if the function is not varargs
3747 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3748 </li>
3749 <li>
3750 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3751 be invoked. In most cases, this is a direct function invocation, but
3752 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3753 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3754 </li>
3755 <li>
3756 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3757 function signature argument types. All arguments must be of
3758 <a href="#t_firstclass">first class</a> type. If the function signature
3759 indicates the function accepts a variable number of arguments, the extra
3760 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3761 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3762</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3764<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3765
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3766<p>The '<tt>call</tt>' instruction is used to cause control flow to
3767transfer to a specified function, with its incoming arguments bound to
3768the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3769instruction in the called function, control flow continues with the
3770instruction after the function call, and the return value of the
3771function is bound to the result argument. This is a simpler case of
3772the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3774<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3775
3776<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3777 %retval = call i32 @test(i32 %argc)
3778 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3779 %X = tail call i32 @foo()
3780 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3781 %Z = call void %foo(i8 97 signext)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3782</pre>
3783
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3784</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3785
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3786<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3787<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3788 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3789</div>
3790
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3791<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3792
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3793<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3794
3795<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3796 &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]3797</pre>
3798
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3799<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3800
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3801<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3802the "variable argument" area of a function call. It is used to implement the
3803<tt>va_arg</tt> macro in C.</p>
3804
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3805<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3806
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3807<p>This instruction takes a <tt>va_list*</tt> value and the type of
3808the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3809increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3810actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3811
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3812<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3813
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3814<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3815type from the specified <tt>va_list</tt> and causes the
3816<tt>va_list</tt> to point to the next argument. For more information,
3817see the variable argument handling <a href="#int_varargs">Intrinsic
3818Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3819
3820<p>It is legal for this instruction to be called in a function which does not
3821take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3822function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3823
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3824<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3825href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3826argument.</p>
3827
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3828<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3829
3830<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3831
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3832</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3833
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3834<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3835<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3836<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3838<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3839
3840<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3841well known names and semantics and are required to follow certain restrictions.
3842Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3843language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3844adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3845
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3846<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3847prefix is reserved in LLVM for intrinsic names; thus, function names may not
3848begin with this prefix. Intrinsic functions must always be external functions:
3849you cannot define the body of intrinsic functions. Intrinsic functions may
3850only be used in call or invoke instructions: it is illegal to take the address
3851of an intrinsic function. Additionally, because intrinsic functions are part
3852of the LLVM language, it is required if any are added that they be documented
3853here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3854
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3855<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3856a family of functions that perform the same operation but on different data
3857types. Because LLVM can represent over 8 million different integer types,
3858overloading is used commonly to allow an intrinsic function to operate on any
3859integer type. One or more of the argument types or the result type can be
3860overloaded to accept any integer type. Argument types may also be defined as
3861exactly matching a previous argument's type or the result type. This allows an
3862intrinsic function which accepts multiple arguments, but needs all of them to
3863be of the same type, to only be overloaded with respect to a single argument or
3864the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3865
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3866<p>Overloaded intrinsics will have the names of its overloaded argument types
3867encoded into its function name, each preceded by a period. Only those types
3868which are overloaded result in a name suffix. Arguments whose type is matched
3869against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3870take an integer of any width and returns an integer of exactly the same integer
3871width. This leads to a family of functions such as
3872<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3873Only one type, the return type, is overloaded, and only one type suffix is
3874required. Because the argument's type is matched against the return type, it
3875does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3876
3877<p>To learn how to add an intrinsic function, please see the
3878<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3879</p>
3880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3881</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3882
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3883<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3884<div class="doc_subsection">
3885 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3886</div>
3887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3888<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3889
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3890<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3891 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3892intrinsic functions. These functions are related to the similarly
3893named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3894
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3895<p>All of these functions operate on arguments that use a
3896target-specific value type "<tt>va_list</tt>". The LLVM assembly
3897language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3898transformations should be prepared to handle these functions regardless of
3899the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3900
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3901<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]3902instruction and the variable argument handling intrinsic functions are
3903used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3904
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3905<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3906<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3907define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3908 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3909 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3910 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3911 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3912
3913 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3914 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3915
3916 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3917 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3918 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3919 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3920 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3921
3922 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3923 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3924 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3925}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3926
3927declare void @llvm.va_start(i8*)
3928declare void @llvm.va_copy(i8*, i8*)
3929declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3930</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3931</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3932
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3933</div>
3934
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3935<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3936<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3937 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3938</div>
3939
3940
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3941<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3942<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3943<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3944<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3945<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3946<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3947href="#i_va_arg">va_arg</a></tt>.</p>
3948
3949<h5>Arguments:</h5>
3950
3951<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3952
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3953<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3954
3955<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3956macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3957<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]3958<tt>va_arg</tt> will produce the first variable argument passed to the function.
3959Unlike 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]3960last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3961
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3962</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3963
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3964<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3965<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3966 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3967</div>
3968
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3969<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3970<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3971<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3972<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3973
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3974<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3975which 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]3976or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3977
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3978<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3979
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3980<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]3981
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3982<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3983
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3984<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]3985macro available in C. In a target-dependent way, it destroys the
3986<tt>va_list</tt> element to which the argument points. Calls to <a
3987href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3988<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3989<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3990
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3991</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3992
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3993<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3994<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3995 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3996</div>
3997
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3998<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3999
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4000<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4001
4002<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4003 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4004</pre>
4005
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4006<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4007
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4008<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4009from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4010
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4011<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4012
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4013<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]4014The 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]4015
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4016
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4017<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4018
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4019<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4020macro available in C. In a target-dependent way, it copies the source
4021<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4022intrinsic is necessary because the <tt><a href="#int_va_start">
4023llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4024example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4025
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4026</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4027
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4028<!-- ======================================================================= -->
4029<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4030 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4031</div>
4032
4033<div class="doc_text">
4034
4035<p>
4036LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4037Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4038These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4039stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4040href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4041Front-ends for type-safe garbage collected languages should generate these
4042intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4043href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4044</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4045
4046<p>The garbage collection intrinsics only operate on objects in the generic
4047 address space (address space zero).</p>
4048
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4049</div>
4050
4051<!-- _______________________________________________________________________ -->
4052<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4053 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4054</div>
4055
4056<div class="doc_text">
4057
4058<h5>Syntax:</h5>
4059
4060<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4061 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4062</pre>
4063
4064<h5>Overview:</h5>
4065
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4066<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]4067the code generator, and allows some metadata to be associated with it.</p>
4068
4069<h5>Arguments:</h5>
4070
4071<p>The first argument specifies the address of a stack object that contains the
4072root pointer. The second pointer (which must be either a constant or a global
4073value address) contains the meta-data to be associated with the root.</p>
4074
4075<h5>Semantics:</h5>
4076
4077<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4078location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4079the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4080intrinsic may only be used in a function which <a href="#gc">specifies a GC
4081algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4082
4083</div>
4084
4085
4086<!-- _______________________________________________________________________ -->
4087<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4088 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4089</div>
4090
4091<div class="doc_text">
4092
4093<h5>Syntax:</h5>
4094
4095<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4096 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4097</pre>
4098
4099<h5>Overview:</h5>
4100
4101<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4102locations, allowing garbage collector implementations that require read
4103barriers.</p>
4104
4105<h5>Arguments:</h5>
4106
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4107<p>The second argument is the address to read from, which should be an address
4108allocated from the garbage collector. The first object is a pointer to the
4109start of the referenced object, if needed by the language runtime (otherwise
4110null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4111
4112<h5>Semantics:</h5>
4113
4114<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4115instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4116garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4117may only be used in a function which <a href="#gc">specifies a GC
4118algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4119
4120</div>
4121
4122
4123<!-- _______________________________________________________________________ -->
4124<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4125 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4126</div>
4127
4128<div class="doc_text">
4129
4130<h5>Syntax:</h5>
4131
4132<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4133 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4134</pre>
4135
4136<h5>Overview:</h5>
4137
4138<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4139locations, allowing garbage collector implementations that require write
4140barriers (such as generational or reference counting collectors).</p>
4141
4142<h5>Arguments:</h5>
4143
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4144<p>The first argument is the reference to store, the second is the start of the
4145object to store it to, and the third is the address of the field of Obj to
4146store to. If the runtime does not require a pointer to the object, Obj may be
4147null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4148
4149<h5>Semantics:</h5>
4150
4151<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4152instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4153garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4154may only be used in a function which <a href="#gc">specifies a GC
4155algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4156
4157</div>
4158
4159
4160
4161<!-- ======================================================================= -->
4162<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4163 <a name="int_codegen">Code Generator Intrinsics</a>
4164</div>
4165
4166<div class="doc_text">
4167<p>
4168These intrinsics are provided by LLVM to expose special features that may only
4169be implemented with code generator support.
4170</p>
4171
4172</div>
4173
4174<!-- _______________________________________________________________________ -->
4175<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4176 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4177</div>
4178
4179<div class="doc_text">
4180
4181<h5>Syntax:</h5>
4182<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4183 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4184</pre>
4185
4186<h5>Overview:</h5>
4187
4188<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4189The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4190target-specific value indicating the return address of the current function
4191or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4192</p>
4193
4194<h5>Arguments:</h5>
4195
4196<p>
4197The argument to this intrinsic indicates which function to return the address
4198for. Zero indicates the calling function, one indicates its caller, etc. The
4199argument is <b>required</b> to be a constant integer value.
4200</p>
4201
4202<h5>Semantics:</h5>
4203
4204<p>
4205The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4206the return address of the specified call frame, or zero if it cannot be
4207identified. The value returned by this intrinsic is likely to be incorrect or 0
4208for arguments other than zero, so it should only be used for debugging purposes.
4209</p>
4210
4211<p>
4212Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4213aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4214source-language caller.
4215</p>
4216</div>
4217
4218
4219<!-- _______________________________________________________________________ -->
4220<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4221 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4222</div>
4223
4224<div class="doc_text">
4225
4226<h5>Syntax:</h5>
4227<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4228 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4229</pre>
4230
4231<h5>Overview:</h5>
4232
4233<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4234The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4235target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4236</p>
4237
4238<h5>Arguments:</h5>
4239
4240<p>
4241The argument to this intrinsic indicates which function to return the frame
4242pointer for. Zero indicates the calling function, one indicates its caller,
4243etc. The argument is <b>required</b> to be a constant integer value.
4244</p>
4245
4246<h5>Semantics:</h5>
4247
4248<p>
4249The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4250the frame address of the specified call frame, or zero if it cannot be
4251identified. The value returned by this intrinsic is likely to be incorrect or 0
4252for arguments other than zero, so it should only be used for debugging purposes.
4253</p>
4254
4255<p>
4256Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4257aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4258source-language caller.
4259</p>
4260</div>
4261
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4262<!-- _______________________________________________________________________ -->
4263<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4264 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4265</div>
4266
4267<div class="doc_text">
4268
4269<h5>Syntax:</h5>
4270<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4271 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4272</pre>
4273
4274<h5>Overview:</h5>
4275
4276<p>
4277The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4278the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4279<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4280features like scoped automatic variable sized arrays in C99.
4281</p>
4282
4283<h5>Semantics:</h5>
4284
4285<p>
4286This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4287href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4288<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4289<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4290state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4291practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4292that were allocated after the <tt>llvm.stacksave</tt> was executed.
4293</p>
4294
4295</div>
4296
4297<!-- _______________________________________________________________________ -->
4298<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4299 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4300</div>
4301
4302<div class="doc_text">
4303
4304<h5>Syntax:</h5>
4305<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4306 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4307</pre>
4308
4309<h5>Overview:</h5>
4310
4311<p>
4312The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4313the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4314href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4315useful for implementing language features like scoped automatic variable sized
4316arrays in C99.
4317</p>
4318
4319<h5>Semantics:</h5>
4320
4321<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4322See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4323</p>
4324
4325</div>
4326
4327
4328<!-- _______________________________________________________________________ -->
4329<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4330 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4331</div>
4332
4333<div class="doc_text">
4334
4335<h5>Syntax:</h5>
4336<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4337 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]4338</pre>
4339
4340<h5>Overview:</h5>
4341
4342
4343<p>
4344The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4345a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4346no
4347effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4348characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4349</p>
4350
4351<h5>Arguments:</h5>
4352
4353<p>
4354<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4355determining if the fetch should be for a read (0) or write (1), and
4356<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4357locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4358<tt>locality</tt> arguments must be constant integers.
4359</p>
4360
4361<h5>Semantics:</h5>
4362
4363<p>
4364This intrinsic does not modify the behavior of the program. In particular,
4365prefetches cannot trap and do not produce a value. On targets that support this
4366intrinsic, the prefetch can provide hints to the processor cache for better
4367performance.
4368</p>
4369
4370</div>
4371
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4372<!-- _______________________________________________________________________ -->
4373<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4374 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4375</div>
4376
4377<div class="doc_text">
4378
4379<h5>Syntax:</h5>
4380<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4381 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4382</pre>
4383
4384<h5>Overview:</h5>
4385
4386
4387<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4388The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4389(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4390code to simulators and other tools. The method is target specific, but it is
4391expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4392The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4393after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4394optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4395correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4396</p>
4397
4398<h5>Arguments:</h5>
4399
4400<p>
4401<tt>id</tt> is a numerical id identifying the marker.
4402</p>
4403
4404<h5>Semantics:</h5>
4405
4406<p>
4407This intrinsic does not modify the behavior of the program. Backends that do not
4408support this intrinisic may ignore it.
4409</p>
4410
4411</div>
4412
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4413<!-- _______________________________________________________________________ -->
4414<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4415 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4416</div>
4417
4418<div class="doc_text">
4419
4420<h5>Syntax:</h5>
4421<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4422 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4423</pre>
4424
4425<h5>Overview:</h5>
4426
4427
4428<p>
4429The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4430counter register (or similar low latency, high accuracy clocks) on those targets
4431that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4432As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4433should only be used for small timings.
4434</p>
4435
4436<h5>Semantics:</h5>
4437
4438<p>
4439When directly supported, reading the cycle counter should not modify any memory.
4440Implementations are allowed to either return a application specific value or a
4441system wide value. On backends without support, this is lowered to a constant 0.
4442</p>
4443
4444</div>
4445
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4446<!-- ======================================================================= -->
4447<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4448 <a name="int_libc">Standard C Library Intrinsics</a>
4449</div>
4450
4451<div class="doc_text">
4452<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4453LLVM provides intrinsics for a few important standard C library functions.
4454These intrinsics allow source-language front-ends to pass information about the
4455alignment of the pointer arguments to the code generator, providing opportunity
4456for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4457</p>
4458
4459</div>
4460
4461<!-- _______________________________________________________________________ -->
4462<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4463 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4464</div>
4465
4466<div class="doc_text">
4467
4468<h5>Syntax:</h5>
4469<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4470 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4471 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4472 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4473 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4474</pre>
4475
4476<h5>Overview:</h5>
4477
4478<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4479The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4480location to the destination location.
4481</p>
4482
4483<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4484Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4485intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4486</p>
4487
4488<h5>Arguments:</h5>
4489
4490<p>
4491The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4492the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4493specifying the number of bytes to copy, and the fourth argument is the alignment
4494of the source and destination locations.
4495</p>
4496
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4497<p>
4498If 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]4499the caller guarantees that both the source and destination pointers are aligned
4500to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4501</p>
4502
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4503<h5>Semantics:</h5>
4504
4505<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4506The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4507location to the destination location, which are not allowed to overlap. It
4508copies "len" bytes of memory over. If the argument is known to be aligned to
4509some boundary, this can be specified as the fourth argument, otherwise it should
4510be set to 0 or 1.
4511</p>
4512</div>
4513
4514
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4517 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4518</div>
4519
4520<div class="doc_text">
4521
4522<h5>Syntax:</h5>
4523<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4524 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4525 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4526 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4527 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4528</pre>
4529
4530<h5>Overview:</h5>
4531
4532<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4533The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4534location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4535'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4536</p>
4537
4538<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4539Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4540intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4541</p>
4542
4543<h5>Arguments:</h5>
4544
4545<p>
4546The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4547the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4548specifying the number of bytes to copy, and the fourth argument is the alignment
4549of the source and destination locations.
4550</p>
4551
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4552<p>
4553If 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]4554the caller guarantees that the source and destination pointers are aligned to
4555that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4556</p>
4557
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4558<h5>Semantics:</h5>
4559
4560<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4561The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4562location to the destination location, which may overlap. It
4563copies "len" bytes of memory over. If the argument is known to be aligned to
4564some boundary, this can be specified as the fourth argument, otherwise it should
4565be set to 0 or 1.
4566</p>
4567</div>
4568
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4569
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4570<!-- _______________________________________________________________________ -->
4571<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4572 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4573</div>
4574
4575<div class="doc_text">
4576
4577<h5>Syntax:</h5>
4578<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4579 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4580 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4581 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4582 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4583</pre>
4584
4585<h5>Overview:</h5>
4586
4587<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4588The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4589byte value.
4590</p>
4591
4592<p>
4593Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4594does not return a value, and takes an extra alignment argument.
4595</p>
4596
4597<h5>Arguments:</h5>
4598
4599<p>
4600The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4601byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4602argument specifying the number of bytes to fill, and the fourth argument is the
4603known alignment of destination location.
4604</p>
4605
4606<p>
4607If 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]4608the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4609</p>
4610
4611<h5>Semantics:</h5>
4612
4613<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4614The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4615the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4616destination location. If the argument is known to be aligned to some boundary,
4617this can be specified as the fourth argument, otherwise it should be set to 0 or
46181.
4619</p>
4620</div>
4621
4622
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4623<!-- _______________________________________________________________________ -->
4624<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4625 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4626</div>
4627
4628<div class="doc_text">
4629
4630<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4631<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]4632floating point or vector of floating point type. Not all targets support all
4633types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4634<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4635 declare float @llvm.sqrt.f32(float %Val)
4636 declare double @llvm.sqrt.f64(double %Val)
4637 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4638 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4639 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4640</pre>
4641
4642<h5>Overview:</h5>
4643
4644<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4645The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4646returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4647<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4648negative numbers (which allows for better optimization).
4649</p>
4650
4651<h5>Arguments:</h5>
4652
4653<p>
4654The argument and return value are floating point numbers of the same type.
4655</p>
4656
4657<h5>Semantics:</h5>
4658
4659<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4660This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4661floating point number.
4662</p>
4663</div>
4664
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4665<!-- _______________________________________________________________________ -->
4666<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4667 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4668</div>
4669
4670<div class="doc_text">
4671
4672<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4673<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]4674floating point or vector of floating point type. Not all targets support all
4675types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4676<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4677 declare float @llvm.powi.f32(float %Val, i32 %power)
4678 declare double @llvm.powi.f64(double %Val, i32 %power)
4679 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4680 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4681 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4682</pre>
4683
4684<h5>Overview:</h5>
4685
4686<p>
4687The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4688specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4689multiplications is not defined. When a vector of floating point type is
4690used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4691</p>
4692
4693<h5>Arguments:</h5>
4694
4695<p>
4696The second argument is an integer power, and the first is a value to raise to
4697that power.
4698</p>
4699
4700<h5>Semantics:</h5>
4701
4702<p>
4703This function returns the first value raised to the second power with an
4704unspecified sequence of rounding operations.</p>
4705</div>
4706
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4707<!-- _______________________________________________________________________ -->
4708<div class="doc_subsubsection">
4709 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4710</div>
4711
4712<div class="doc_text">
4713
4714<h5>Syntax:</h5>
4715<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4716floating point or vector of floating point type. Not all targets support all
4717types however.
4718<pre>
4719 declare float @llvm.sin.f32(float %Val)
4720 declare double @llvm.sin.f64(double %Val)
4721 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4722 declare fp128 @llvm.sin.f128(fp128 %Val)
4723 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4724</pre>
4725
4726<h5>Overview:</h5>
4727
4728<p>
4729The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4730</p>
4731
4732<h5>Arguments:</h5>
4733
4734<p>
4735The argument and return value are floating point numbers of the same type.
4736</p>
4737
4738<h5>Semantics:</h5>
4739
4740<p>
4741This function returns the sine of the specified operand, returning the
4742same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4743conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4744</div>
4745
4746<!-- _______________________________________________________________________ -->
4747<div class="doc_subsubsection">
4748 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4749</div>
4750
4751<div class="doc_text">
4752
4753<h5>Syntax:</h5>
4754<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4755floating point or vector of floating point type. Not all targets support all
4756types however.
4757<pre>
4758 declare float @llvm.cos.f32(float %Val)
4759 declare double @llvm.cos.f64(double %Val)
4760 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4761 declare fp128 @llvm.cos.f128(fp128 %Val)
4762 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4763</pre>
4764
4765<h5>Overview:</h5>
4766
4767<p>
4768The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4769</p>
4770
4771<h5>Arguments:</h5>
4772
4773<p>
4774The argument and return value are floating point numbers of the same type.
4775</p>
4776
4777<h5>Semantics:</h5>
4778
4779<p>
4780This function returns the cosine of the specified operand, returning the
4781same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4782conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4783</div>
4784
4785<!-- _______________________________________________________________________ -->
4786<div class="doc_subsubsection">
4787 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4788</div>
4789
4790<div class="doc_text">
4791
4792<h5>Syntax:</h5>
4793<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4794floating point or vector of floating point type. Not all targets support all
4795types however.
4796<pre>
4797 declare float @llvm.pow.f32(float %Val, float %Power)
4798 declare double @llvm.pow.f64(double %Val, double %Power)
4799 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4800 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4801 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4802</pre>
4803
4804<h5>Overview:</h5>
4805
4806<p>
4807The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4808specified (positive or negative) power.
4809</p>
4810
4811<h5>Arguments:</h5>
4812
4813<p>
4814The second argument is a floating point power, and the first is a value to
4815raise to that power.
4816</p>
4817
4818<h5>Semantics:</h5>
4819
4820<p>
4821This function returns the first value raised to the second power,
4822returning the
4823same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4824conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4825</div>
4826
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4827
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4828<!-- ======================================================================= -->
4829<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4830 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4831</div>
4832
4833<div class="doc_text">
4834<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4835LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4836These allow efficient code generation for some algorithms.
4837</p>
4838
4839</div>
4840
4841<!-- _______________________________________________________________________ -->
4842<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4843 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4844</div>
4845
4846<div class="doc_text">
4847
4848<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4849<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4850type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4851<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4852 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4853 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4854 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4855</pre>
4856
4857<h5>Overview:</h5>
4858
4859<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4860The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4861values with an even number of bytes (positive multiple of 16 bits). These are
4862useful for performing operations on data that is not in the target's native
4863byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4864</p>
4865
4866<h5>Semantics:</h5>
4867
4868<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4869The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4870and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4871intrinsic returns an i32 value that has the four bytes of the input i32
4872swapped, 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]4873i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4874<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4875additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4876</p>
4877
4878</div>
4879
4880<!-- _______________________________________________________________________ -->
4881<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4882 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4883</div>
4884
4885<div class="doc_text">
4886
4887<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4888<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4889width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4890<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4891 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4892 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4893 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4894 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4895 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4896</pre>
4897
4898<h5>Overview:</h5>
4899
4900<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4901The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4902value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4903</p>
4904
4905<h5>Arguments:</h5>
4906
4907<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4908The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4909integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4910</p>
4911
4912<h5>Semantics:</h5>
4913
4914<p>
4915The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4916</p>
4917</div>
4918
4919<!-- _______________________________________________________________________ -->
4920<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4921 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4922</div>
4923
4924<div class="doc_text">
4925
4926<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4927<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4928integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4929<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4930 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4931 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4932 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4933 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4934 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
4938
4939<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4940The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4941leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4942</p>
4943
4944<h5>Arguments:</h5>
4945
4946<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4947The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4948integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4949</p>
4950
4951<h5>Semantics:</h5>
4952
4953<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4954The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4955in 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]4956of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4957</p>
4958</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4959
4960
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4961
4962<!-- _______________________________________________________________________ -->
4963<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4964 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4965</div>
4966
4967<div class="doc_text">
4968
4969<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4970<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4971integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4972<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4973 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4974 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4975 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4976 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4977 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4978</pre>
4979
4980<h5>Overview:</h5>
4981
4982<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4983The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4984trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4985</p>
4986
4987<h5>Arguments:</h5>
4988
4989<p>
4990The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4991integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4992</p>
4993
4994<h5>Semantics:</h5>
4995
4996<p>
4997The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4998in a variable. If the src == 0 then the result is the size in bits of the type
4999of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5000</p>
5001</div>
5002
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5003<!-- _______________________________________________________________________ -->
5004<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5005 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5006</div>
5007
5008<div class="doc_text">
5009
5010<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5011<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5012on any integer bit width.
5013<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5014 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5015 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5016</pre>
5017
5018<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5019<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5020range of bits from an integer value and returns them in the same bit width as
5021the original value.</p>
5022
5023<h5>Arguments:</h5>
5024<p>The first argument, <tt>%val</tt> and the result may be integer types of
5025any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5026arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5027
5028<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5029<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5030of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5031<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5032operates in forward mode.</p>
5033<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5034right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5035only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5036<ol>
5037 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5038 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5039 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5040 to determine the number of bits to retain.</li>
5041 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5042 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5043</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5044<p>In reverse mode, a similar computation is made except that the bits are
5045returned in the reverse order. So, for example, if <tt>X</tt> has the value
5046<tt>i16 0x0ACF (101011001111)</tt> and we apply
5047<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5048<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5049</div>
5050
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5051<div class="doc_subsubsection">
5052 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5053</div>
5054
5055<div class="doc_text">
5056
5057<h5>Syntax:</h5>
5058<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5059on any integer bit width.
5060<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5061 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5062 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]5063</pre>
5064
5065<h5>Overview:</h5>
5066<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5067of bits in an integer value with another integer value. It returns the integer
5068with the replaced bits.</p>
5069
5070<h5>Arguments:</h5>
5071<p>The first argument, <tt>%val</tt> and the result may be integer types of
5072any bit width but they must have the same bit width. <tt>%val</tt> is the value
5073whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5074integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5075type since they specify only a bit index.</p>
5076
5077<h5>Semantics:</h5>
5078<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5079of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5080<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5081operates in forward mode.</p>
5082<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5083truncating it down to the size of the replacement area or zero extending it
5084up to that size.</p>
5085<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5086are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5087in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5088to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5089<p>In reverse mode, a similar computation is made except that the bits are
5090reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5091<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]5092<h5>Examples:</h5>
5093<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5094 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5095 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5096 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5097 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5098 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5099</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5100</div>
5101
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5102<!-- ======================================================================= -->
5103<div class="doc_subsection">
5104 <a name="int_debugger">Debugger Intrinsics</a>
5105</div>
5106
5107<div class="doc_text">
5108<p>
5109The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5110are described in the <a
5111href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5112Debugging</a> document.
5113</p>
5114</div>
5115
5116
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5117<!-- ======================================================================= -->
5118<div class="doc_subsection">
5119 <a name="int_eh">Exception Handling Intrinsics</a>
5120</div>
5121
5122<div class="doc_text">
5123<p> The LLVM exception handling intrinsics (which all start with
5124<tt>llvm.eh.</tt> prefix), are described in the <a
5125href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5126Handling</a> document. </p>
5127</div>
5128
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5129<!-- ======================================================================= -->
5130<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5131 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5132</div>
5133
5134<div class="doc_text">
5135<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5136 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5137 the <tt>nest</tt> attribute, from a function. The result is a callable
5138 function pointer lacking the nest parameter - the caller does not need
5139 to provide a value for it. Instead, the value to use is stored in
5140 advance in a "trampoline", a block of memory usually allocated
5141 on the stack, which also contains code to splice the nest value into the
5142 argument list. This is used to implement the GCC nested function address
5143 extension.
5144</p>
5145<p>
5146 For example, if the function is
5147 <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]5148 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]5149<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5150 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5151 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5152 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5153 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5154</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5155 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5156 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5157</div>
5158
5159<!-- _______________________________________________________________________ -->
5160<div class="doc_subsubsection">
5161 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5162</div>
5163<div class="doc_text">
5164<h5>Syntax:</h5>
5165<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5166declare 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]5167</pre>
5168<h5>Overview:</h5>
5169<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5170 This fills the memory pointed to by <tt>tramp</tt> with code
5171 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5172</p>
5173<h5>Arguments:</h5>
5174<p>
5175 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5176 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5177 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5178 intrinsic. Note that the size and the alignment are target-specific - LLVM
5179 currently provides no portable way of determining them, so a front-end that
5180 generates this intrinsic needs to have some target-specific knowledge.
5181 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]5182</p>
5183<h5>Semantics:</h5>
5184<p>
5185 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5186 dependent code, turning it into a function. A pointer to this function is
5187 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5188 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5189 before being called. The new function's signature is the same as that of
5190 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5191 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5192 of pointer type. Calling the new function is equivalent to calling
5193 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5194 missing <tt>nest</tt> argument. If, after calling
5195 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5196 modified, then the effect of any later call to the returned function pointer is
5197 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5198</p>
5199</div>
5200
5201<!-- ======================================================================= -->
5202<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5203 <a name="int_general">General Intrinsics</a>
5204</div>
5205
5206<div class="doc_text">
5207<p> This class of intrinsics is designed to be generic and has
5208no specific purpose. </p>
5209</div>
5210
5211<!-- _______________________________________________________________________ -->
5212<div class="doc_subsubsection">
5213 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5214</div>
5215
5216<div class="doc_text">
5217
5218<h5>Syntax:</h5>
5219<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5220 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]5221</pre>
5222
5223<h5>Overview:</h5>
5224
5225<p>
5226The '<tt>llvm.var.annotation</tt>' intrinsic
5227</p>
5228
5229<h5>Arguments:</h5>
5230
5231<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5232The first argument is a pointer to a value, the second is a pointer to a
5233global string, the third is a pointer to a global string which is the source
5234file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5235</p>
5236
5237<h5>Semantics:</h5>
5238
5239<p>
5240This intrinsic allows annotation of local variables with arbitrary strings.
5241This can be useful for special purpose optimizations that want to look for these
5242 annotations. These have no other defined use, they are ignored by code
5243 generation and optimization.
5244</div>
5245
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5246<!-- _______________________________________________________________________ -->
5247<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5248 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5249</div>
5250
5251<div class="doc_text">
5252
5253<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5254<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5255any integer bit width.
5256</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5257<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5258 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5259 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5260 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5261 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5262 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]5263</pre>
5264
5265<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5266
5267<p>
5268The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5269</p>
5270
5271<h5>Arguments:</h5>
5272
5273<p>
5274The first argument is an integer value (result of some expression),
5275the second is a pointer to a global string, the third is a pointer to a global
5276string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5277It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5278</p>
5279
5280<h5>Semantics:</h5>
5281
5282<p>
5283This intrinsic allows annotations to be put on arbitrary expressions
5284with arbitrary strings. This can be useful for special purpose optimizations
5285that want to look for these annotations. These have no other defined use, they
5286are ignored by code generation and optimization.
5287</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5289<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5290<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5291<address>
5292 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5293 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5294 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5295 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5296
5297 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5298 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5299 Last modified: $Date$
5300</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5301
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5302</body>
5303</html>