Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 09fed25a07287d12ba74ec5f00b479fe1a9b56b7 / . / docs / LangRef.html
blob: 236538d3e48a869c603c6704d493a8941da3185d [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>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]52 </ol>
53 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]58 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 </ol>
65 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]68 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]73 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]74 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]78 </ol>
79 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]80 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]81 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]88 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]89 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 </ol>
133 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]149 </ol>
150 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]158 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]159 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
160 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]167 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]181 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]195 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]196 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </ol>
203 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]209 </ol>
210 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]220 </ol>
221 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 </ol>
233 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]235 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]249 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]250 </ol>
251 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]285 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]294 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]295 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296 </ol>
297 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]298</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]299
300<div class="doc_author">
301 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
302 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]303</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]304
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]305<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]306<div class="doc_section"> <a name="abstract">Abstract </a></div>
307<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]308
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]309<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]310
311<p>This document is a reference manual for the LLVM assembly language. LLVM is
312 a Static Single Assignment (SSA) based representation that provides type
313 safety, low-level operations, flexibility, and the capability of representing
314 'all' high-level languages cleanly. It is the common code representation
315 used throughout all phases of the LLVM compilation strategy.</p>
316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]317</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]319<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]320<div class="doc_section"> <a name="introduction">Introduction</a> </div>
321<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]323<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM code representation is designed to be used in three different forms:
326 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
327 for fast loading by a Just-In-Time compiler), and as a human readable
328 assembly language representation. This allows LLVM to provide a powerful
329 intermediate representation for efficient compiler transformations and
330 analysis, while providing a natural means to debug and visualize the
331 transformations. The three different forms of LLVM are all equivalent. This
332 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]334<p>The LLVM representation aims to be light-weight and low-level while being
335 expressive, typed, and extensible at the same time. It aims to be a
336 "universal IR" of sorts, by being at a low enough level that high-level ideas
337 may be cleanly mapped to it (similar to how microprocessors are "universal
338 IR's", allowing many source languages to be mapped to them). By providing
339 type information, LLVM can be used as the target of optimizations: for
340 example, through pointer analysis, it can be proven that a C automatic
341 variable is never accessed outside of the current function... allowing it to
342 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]344</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]346<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]347<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]349<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>It is important to note that this document describes 'well formed' LLVM
352 assembly language. There is a difference between what the parser accepts and
353 what is considered 'well formed'. For example, the following instruction is
354 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]355
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]356<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]357<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]362<p>...because the definition of <tt>%x</tt> does not dominate all of its
363 uses. The LLVM infrastructure provides a verification pass that may be used
364 to verify that an LLVM module is well formed. This pass is automatically run
365 by the parser after parsing input assembly and by the optimizer before it
366 outputs bitcode. The violations pointed out by the verifier pass indicate
367 bugs in transformation passes or input to the parser.</p>
368
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]369</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]371<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]373<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]374<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]375<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]377<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]379<p>LLVM identifiers come in two basic types: global and local. Global
380 identifiers (functions, global variables) begin with the <tt>'@'</tt>
381 character. Local identifiers (register names, types) begin with
382 the <tt>'%'</tt> character. Additionally, there are three different formats
383 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]385<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]386 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]387 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
388 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
389 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
390 other characters in their names can be surrounded with quotes. Special
391 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
392 ASCII code for the character in hexadecimal. In this way, any character
393 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]395 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]397
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]398 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]399 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]400</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]401
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 don't need to worry about name clashes with reserved words, and the set of
404 reserved words may be expanded in the future without penalty. Additionally,
405 unnamed identifiers allow a compiler to quickly come up with a temporary
406 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]407
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]408<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]409 languages. There are keywords for different opcodes
410 ('<tt><a href="#i_add">add</a></tt>',
411 '<tt><a href="#i_bitcast">bitcast</a></tt>',
412 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
413 ('<tt><a href="#t_void">void</a></tt>',
414 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
415 reserved words cannot conflict with variable names, because none of them
416 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
418<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]421<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]423<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]425%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]427</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]429<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]433%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]435</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
443%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]445</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]447<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
448 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]450<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]452 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
454 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]455 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]457 <li>Unnamed temporaries are numbered sequentially</li>
458</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]460<p>...and it also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461 demonstrating instructions, we will follow an instruction with a comment that
462 defines the type and name of value produced. Comments are shown in italic
463 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]465</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]466
467<!-- *********************************************************************** -->
468<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
469<!-- *********************************************************************** -->
470
471<!-- ======================================================================= -->
472<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
473</div>
474
475<div class="doc_text">
476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]477<p>LLVM programs are composed of "Module"s, each of which is a translation unit
478 of the input programs. Each module consists of functions, global variables,
479 and symbol table entries. Modules may be combined together with the LLVM
480 linker, which merges function (and global variable) definitions, resolves
481 forward declarations, and merges symbol table entries. Here is an example of
482 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]484<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]486<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
487 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]488
489<i>; External declaration of the puts function</i>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]490<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491
492<i>; Definition of main function</i>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]494 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495 %cast210 = <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]496 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]497
498 <i>; Call puts function to write out the string to stdout...</i>
499 <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]500 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]502 href="#i_ret">ret</a> i32 0<br>}<br>
503</pre>
504</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]506<p>This example is made up of a <a href="#globalvars">global variable</a> named
507 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
508 a <a href="#functionstructure">function definition</a> for
509 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]511<p>In general, a module is made up of a list of global values, where both
512 functions and global variables are global values. Global values are
513 represented by a pointer to a memory location (in this case, a pointer to an
514 array of char, and a pointer to a function), and have one of the
515 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]516
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]517</div>
518
519<!-- ======================================================================= -->
520<div class="doc_subsection">
521 <a name="linkage">Linkage Types</a>
522</div>
523
524<div class="doc_text">
525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]526<p>All Global Variables and Functions have one of the following types of
527 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
529<dl>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]531 <dd>Global values with private linkage are only directly accessible by objects
532 in the current module. In particular, linking code into a module with an
533 private global value may cause the private to be renamed as necessary to
534 avoid collisions. Because the symbol is private to the module, all
535 references can be updated. This doesn't show up in any symbol table in the
536 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]537
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]539 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]540 removed by the linker after evaluation. Note that (unlike private
541 symbols) linker_private symbols are subject to coalescing by the linker:
542 weak symbols get merged and redefinitions are rejected. However, unlike
543 normal strong symbols, they are removed by the linker from the final
544 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]545
Dale Johannesen2307a7f2008-05-23 23:13:41 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]547 <dd>Similar to private, but the value shows as a local symbol
548 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
549 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]550
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]552 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]553 into the object file corresponding to the LLVM module. They exist to
554 allow inlining and other optimizations to take place given knowledge of
555 the definition of the global, which is known to be somewhere outside the
556 module. Globals with <tt>available_externally</tt> linkage are allowed to
557 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
558 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]559
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]561 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]562 the same name when linkage occurs. This is typically used to implement
563 inline functions, templates, or other code which must be generated in each
564 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
565 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]566
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]568 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
569 <tt>linkonce</tt> linkage, except that unreferenced globals with
570 <tt>weak</tt> linkage may not be discarded. This is used for globals that
571 are declared "weak" in C source code.</dd>
572
573 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
574 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
575 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
576 global scope.
577 Symbols with "<tt>common</tt>" linkage are merged in the same way as
578 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]579 <tt>common</tt> symbols may not have an explicit section,
580 must have a zero initializer, and may not be marked '<a
581 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
582 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]583
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]584
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]586 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]587 pointer to array type. When two global variables with appending linkage
588 are linked together, the two global arrays are appended together. This is
589 the LLVM, typesafe, equivalent of having the system linker append together
590 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]591
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]593 <dd>The semantics of this linkage follow the ELF object file model: the symbol
594 is weak until linked, if not linked, the symbol becomes null instead of
595 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]596
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
598 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]599 <dd>Some languages allow differing globals to be merged, such as two functions
600 with different semantics. Other languages, such as <tt>C++</tt>, ensure
601 that only equivalent globals are ever merged (the "one definition rule" -
602 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
603 and <tt>weak_odr</tt> linkage types to indicate that the global will only
604 be merged with equivalent globals. These linkage types are otherwise the
605 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]606
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]607 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]608 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]609 visible, meaning that it participates in linkage and can be used to
610 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]611</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]613<p>The next two types of linkage are targeted for Microsoft Windows platform
614 only. They are designed to support importing (exporting) symbols from (to)
615 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617<dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]619 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620 or variable via a global pointer to a pointer that is set up by the DLL
621 exporting the symbol. On Microsoft Windows targets, the pointer name is
622 formed by combining <code>__imp_</code> and the function or variable
623 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]624
625 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]626 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]627 pointer to a pointer in a DLL, so that it can be referenced with the
628 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
629 name is formed by combining <code>__imp_</code> and the function or
630 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]631</dl>
632
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
634 another module defined a "<tt>.LC0</tt>" variable and was linked with this
635 one, one of the two would be renamed, preventing a collision. Since
636 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
637 declarations), they are accessible outside of the current module.</p>
638
639<p>It is illegal for a function <i>declaration</i> to have any linkage type
640 other than "externally visible", <tt>dllimport</tt>
641 or <tt>extern_weak</tt>.</p>
642
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]643<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644 or <tt>weak_odr</tt> linkages.</p>
645
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]646</div>
647
648<!-- ======================================================================= -->
649<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]650 <a name="callingconv">Calling Conventions</a>
651</div>
652
653<div class="doc_text">
654
655<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]656 and <a href="#i_invoke">invokes</a> can all have an optional calling
657 convention specified for the call. The calling convention of any pair of
658 dynamic caller/callee must match, or the behavior of the program is
659 undefined. The following calling conventions are supported by LLVM, and more
660 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661
662<dl>
663 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]664 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]665 specified) matches the target C calling conventions. This calling
666 convention supports varargs function calls and tolerates some mismatch in
667 the declared prototype and implemented declaration of the function (as
668 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]669
670 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]671 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]672 (e.g. by passing things in registers). This calling convention allows the
673 target to use whatever tricks it wants to produce fast code for the
674 target, without having to conform to an externally specified ABI
675 (Application Binary Interface). Implementations of this convention should
676 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
677 optimization</a> to be supported. This calling convention does not
678 support varargs and requires the prototype of all callees to exactly match
679 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680
681 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]683 as possible under the assumption that the call is not commonly executed.
684 As such, these calls often preserve all registers so that the call does
685 not break any live ranges in the caller side. This calling convention
686 does not support varargs and requires the prototype of all callees to
687 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]688
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]689 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]691 target-specific calling conventions to be used. Target specific calling
692 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]693</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 support Pascal conventions or any other well-known target-independent
697 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]698
699</div>
700
701<!-- ======================================================================= -->
702<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]703 <a name="visibility">Visibility Styles</a>
704</div>
705
706<div class="doc_text">
707
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708<p>All Global Variables and Functions have one of the following visibility
709 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]710
711<dl>
712 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]713 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 that the declaration is visible to other modules and, in shared libraries,
715 means that the declared entity may be overridden. On Darwin, default
716 visibility means that the declaration is visible to other modules. Default
717 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]718
719 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]720 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]721 object if they are in the same shared object. Usually, hidden visibility
722 indicates that the symbol will not be placed into the dynamic symbol
723 table, so no other module (executable or shared library) can reference it
724 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]725
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]726 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]727 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]728 the dynamic symbol table, but that references within the defining module
729 will bind to the local symbol. That is, the symbol cannot be overridden by
730 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]731</dl>
732
733</div>
734
735<!-- ======================================================================= -->
736<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]737 <a name="namedtypes">Named Types</a>
738</div>
739
740<div class="doc_text">
741
742<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]743 it easier to read the IR and make the IR more condensed (particularly when
744 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]745
746<div class="doc_code">
747<pre>
748%mytype = type { %mytype*, i32 }
749</pre>
750</div>
751
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]752<p>You may give a name to any <a href="#typesystem">type</a> except
753 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
754 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]755
756<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]757 and that you can therefore specify multiple names for the same type. This
758 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
759 uses structural typing, the name is not part of the type. When printing out
760 LLVM IR, the printer will pick <em>one name</em> to render all types of a
761 particular shape. This means that if you have code where two different
762 source types end up having the same LLVM type, that the dumper will sometimes
763 print the "wrong" or unexpected type. This is an important design point and
764 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]765
766</div>
767
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]768<!-- ======================================================================= -->
769<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]770 <a name="globalvars">Global Variables</a>
771</div>
772
773<div class="doc_text">
774
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]775<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]776 instead of run-time. Global variables may optionally be initialized, may
777 have an explicit section to be placed in, and may have an optional explicit
778 alignment specified. A variable may be defined as "thread_local", which
779 means that it will not be shared by threads (each thread will have a
780 separated copy of the variable). A variable may be defined as a global
781 "constant," which indicates that the contents of the variable
782 will <b>never</b> be modified (enabling better optimization, allowing the
783 global data to be placed in the read-only section of an executable, etc).
784 Note that variables that need runtime initialization cannot be marked
785 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]786
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]787<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
788 constant, even if the final definition of the global is not. This capability
789 can be used to enable slightly better optimization of the program, but
790 requires the language definition to guarantee that optimizations based on the
791 'constantness' are valid for the translation units that do not include the
792 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794<p>As SSA values, global variables define pointer values that are in scope
795 (i.e. they dominate) all basic blocks in the program. Global variables
796 always define a pointer to their "content" type because they describe a
797 region of memory, and all memory objects in LLVM are accessed through
798 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]800<p>A global variable may be declared to reside in a target-specific numbered
801 address space. For targets that support them, address spaces may affect how
802 optimizations are performed and/or what target instructions are used to
803 access the variable. The default address space is zero. The address space
804 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]805
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]806<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]808
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]809<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]810 the alignment is set to zero, the alignment of the global is set by the
811 target to whatever it feels convenient. If an explicit alignment is
812 specified, the global is forced to have at least that much alignment. All
813 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]815<p>For example, the following defines a global in a numbered address space with
816 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]817
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]818<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]819<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]820@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]821</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]822</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]823
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]824</div>
825
826
827<!-- ======================================================================= -->
828<div class="doc_subsection">
829 <a name="functionstructure">Functions</a>
830</div>
831
832<div class="doc_text">
833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]834<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
835 optional <a href="#linkage">linkage type</a>, an optional
836 <a href="#visibility">visibility style</a>, an optional
837 <a href="#callingconv">calling convention</a>, a return type, an optional
838 <a href="#paramattrs">parameter attribute</a> for the return type, a function
839 name, a (possibly empty) argument list (each with optional
840 <a href="#paramattrs">parameter attributes</a>), optional
841 <a href="#fnattrs">function attributes</a>, an optional section, an optional
842 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
843 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
846 optional <a href="#linkage">linkage type</a>, an optional
847 <a href="#visibility">visibility style</a>, an optional
848 <a href="#callingconv">calling convention</a>, a return type, an optional
849 <a href="#paramattrs">parameter attribute</a> for the return type, a function
850 name, a possibly empty list of arguments, an optional alignment, and an
851 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]852
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]853<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]854 (Control Flow Graph) for the function. Each basic block may optionally start
855 with a label (giving the basic block a symbol table entry), contains a list
856 of instructions, and ends with a <a href="#terminators">terminator</a>
857 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]858
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]859<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]860 executed on entrance to the function, and it is not allowed to have
861 predecessor basic blocks (i.e. there can not be any branches to the entry
862 block of a function). Because the block can have no predecessors, it also
863 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]864
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]865<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]866 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]867
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]868<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]869 the alignment is set to zero, the alignment of the function is set by the
870 target to whatever it feels convenient. If an explicit alignment is
871 specified, the function is forced to have at least that much alignment. All
872 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]873
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]874<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]875<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]876<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]877define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]878 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
879 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
880 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
881 [<a href="#gc">gc</a>] { ... }
882</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]883</div>
884
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]885</div>
886
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]887<!-- ======================================================================= -->
888<div class="doc_subsection">
889 <a name="aliasstructure">Aliases</a>
890</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]891
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]892<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893
894<p>Aliases act as "second name" for the aliasee value (which can be either
895 function, global variable, another alias or bitcast of global value). Aliases
896 may have an optional <a href="#linkage">linkage type</a>, and an
897 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]898
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]899<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]900<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]901<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]902@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]903</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]904</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]905
906</div>
907
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]908<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]909<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911<div class="doc_text">
912
913<p>The return type and each parameter of a function type may have a set of
914 <i>parameter attributes</i> associated with them. Parameter attributes are
915 used to communicate additional information about the result or parameters of
916 a function. Parameter attributes are considered to be part of the function,
917 not of the function type, so functions with different parameter attributes
918 can have the same function type.</p>
919
920<p>Parameter attributes are simple keywords that follow the type specified. If
921 multiple parameter attributes are needed, they are space separated. For
922 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]923
924<div class="doc_code">
925<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]926declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]927declare i32 @atoi(i8 zeroext)
928declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]929</pre>
930</div>
931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932<p>Note that any attributes for the function result (<tt>nounwind</tt>,
933 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]934
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]936
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]937<dl>
938 <dt><tt>zeroext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]939 <dd>This indicates to the code generator that the parameter or return value
940 should be zero-extended to a 32-bit value by the caller (for a parameter)
941 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]942
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]943 <dt><tt>signext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]944 <dd>This indicates to the code generator that the parameter or return value
945 should be sign-extended to a 32-bit value by the caller (for a parameter)
946 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]947
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]948 <dt><tt>inreg</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]949 <dd>This indicates that this parameter or return value should be treated in a
950 special target-dependent fashion during while emitting code for a function
951 call or return (usually, by putting it in a register as opposed to memory,
952 though some targets use it to distinguish between two different kinds of
953 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]954
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]955 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]956 <dd>This indicates that the pointer parameter should really be passed by value
957 to the function. The attribute implies that a hidden copy of the pointee
958 is made between the caller and the callee, so the callee is unable to
959 modify the value in the callee. This attribute is only valid on LLVM
960 pointer arguments. It is generally used to pass structs and arrays by
961 value, but is also valid on pointers to scalars. The copy is considered
962 to belong to the caller not the callee (for example,
963 <tt><a href="#readonly">readonly</a></tt> functions should not write to
964 <tt>byval</tt> parameters). This is not a valid attribute for return
965 values. The byval attribute also supports specifying an alignment with
966 the align attribute. This has a target-specific effect on the code
967 generator that usually indicates a desired alignment for the synthesized
968 stack slot.</dd>
969
970 <dt><tt>sret</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer parameter specifies the address of a
972 structure that is the return value of the function in the source program.
973 This pointer must be guaranteed by the caller to be valid: loads and
974 stores to the structure may be assumed by the callee to not to trap. This
975 may only be applied to the first parameter. This is not a valid attribute
976 for return values. </dd>
977
978 <dt><tt>noalias</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]979 <dd>This indicates that the pointer does not alias any global or any other
980 parameter. The caller is responsible for ensuring that this is the
981 case. On a function return value, <tt>noalias</tt> additionally indicates
982 that the pointer does not alias any other pointers visible to the
983 caller. For further details, please see the discussion of the NoAlias
984 response in
985 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
986 analysis</a>.</dd>
987
988 <dt><tt>nocapture</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]989 <dd>This indicates that the callee does not make any copies of the pointer
990 that outlive the callee itself. This is not a valid attribute for return
991 values.</dd>
992
993 <dt><tt>nest</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter can be excised using the
995 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
996 attribute for return values.</dd>
997</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]998
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]999</div>
1000
1001<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1002<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1003 <a name="gc">Garbage Collector Names</a>
1004</div>
1005
1006<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1008<p>Each function may specify a garbage collector name, which is simply a
1009 string:</p>
1010
1011<div class="doc_code">
1012<pre>
1013define void @f() gc "name" { ...
1014</pre>
1015</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1016
1017<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1018 collector which will cause the compiler to alter its output in order to
1019 support the named garbage collection algorithm.</p>
1020
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1021</div>
1022
1023<!-- ======================================================================= -->
1024<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1025 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1026</div>
1027
1028<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1029
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1030<p>Function attributes are set to communicate additional information about a
1031 function. Function attributes are considered to be part of the function, not
1032 of the function type, so functions with different parameter attributes can
1033 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1034
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1035<p>Function attributes are simple keywords that follow the type specified. If
1036 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1037
1038<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1039<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1040define void @f() noinline { ... }
1041define void @f() alwaysinline { ... }
1042define void @f() alwaysinline optsize { ... }
1043define void @f() optsize
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1045</div>
1046
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1047<dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1048 <dt><tt>alwaysinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This attribute indicates that the inliner should attempt to inline this
1050 function into callers whenever possible, ignoring any active inlining size
1051 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1052
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1053 <dt><tt>inlinehint</tt></dt>
1054 <dd>This attribute indicates that the source code contained a hint that inlining
1055 this function is desirable (such as the "inline" keyword in C/C++). It
1056 is just a hint; it imposes no requirements on the inliner.</dd>
1057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1058 <dt><tt>noinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This attribute indicates that the inliner should never inline this
1060 function in any situation. This attribute may not be used together with
1061 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1063 <dt><tt>optsize</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This attribute suggests that optimization passes and code generator passes
1065 make choices that keep the code size of this function low, and otherwise
1066 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1068 <dt><tt>noreturn</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This function attribute indicates that the function never returns
1070 normally. This produces undefined behavior at runtime if the function
1071 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1072
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1073 <dt><tt>nounwind</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This function attribute indicates that the function never returns with an
1075 unwind or exceptional control flow. If the function does unwind, its
1076 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078 <dt><tt>readnone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1079 <dd>This attribute indicates that the function computes its result (or decides
1080 to unwind an exception) based strictly on its arguments, without
1081 dereferencing any pointer arguments or otherwise accessing any mutable
1082 state (e.g. memory, control registers, etc) visible to caller functions.
1083 It does not write through any pointer arguments
1084 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1085 changes any state visible to callers. This means that it cannot unwind
1086 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1087 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This attribute indicates that the function does not write through any
1091 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1092 arguments) or otherwise modify any state (e.g. memory, control registers,
1093 etc) visible to caller functions. It may dereference pointer arguments
1094 and read state that may be set in the caller. A readonly function always
1095 returns the same value (or unwinds an exception identically) when called
1096 with the same set of arguments and global state. It cannot unwind an
1097 exception by calling the <tt>C++</tt> exception throwing methods, but may
1098 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1100 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This attribute indicates that the function should emit a stack smashing
1102 protector. It is in the form of a "canary"&mdash;a random value placed on
1103 the stack before the local variables that's checked upon return from the
1104 function to see if it has been overwritten. A heuristic is used to
1105 determine if a function needs stack protectors or not.<br>
1106<br>
1107 If a function that has an <tt>ssp</tt> attribute is inlined into a
1108 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1109 function will have an <tt>ssp</tt> attribute.</dd>
1110
1111 <dt><tt>sspreq</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This attribute indicates that the function should <em>always</em> emit a
1113 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1114 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1115<br>
1116 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1117 function that doesn't have an <tt>sspreq</tt> attribute or which has
1118 an <tt>ssp</tt> attribute, then the resulting function will have
1119 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120
1121 <dt><tt>noredzone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the code generator should not use a red
1123 zone, even if the target-specific ABI normally permits it.</dd>
1124
1125 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attributes disables implicit floating point instructions.</dd>
1127
1128 <dt><tt>naked</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute disables prologue / epilogue emission for the function.
1130 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1131</dl>
1132
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1133</div>
1134
1135<!-- ======================================================================= -->
1136<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1137 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1138</div>
1139
1140<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1141
1142<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1143 the GCC "file scope inline asm" blocks. These blocks are internally
1144 concatenated by LLVM and treated as a single unit, but may be separated in
1145 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1146
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1147<div class="doc_code">
1148<pre>
1149module asm "inline asm code goes here"
1150module asm "more can go here"
1151</pre>
1152</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1153
1154<p>The strings can contain any character by escaping non-printable characters.
1155 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1156 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1158<p>The inline asm code is simply printed to the machine code .s file when
1159 assembly code is generated.</p>
1160
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1161</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1162
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1163<!-- ======================================================================= -->
1164<div class="doc_subsection">
1165 <a name="datalayout">Data Layout</a>
1166</div>
1167
1168<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1170<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 data is to be laid out in memory. The syntax for the data layout is
1172 simply:</p>
1173
1174<div class="doc_code">
1175<pre>
1176target datalayout = "<i>layout specification</i>"
1177</pre>
1178</div>
1179
1180<p>The <i>layout specification</i> consists of a list of specifications
1181 separated by the minus sign character ('-'). Each specification starts with
1182 a letter and may include other information after the letter to define some
1183 aspect of the data layout. The specifications accepted are as follows:</p>
1184
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1185<dl>
1186 <dt><tt>E</tt></dt>
1187 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1188 bits with the most significance have the lowest address location.</dd>
1189
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1190 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1191 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1192 the bits with the least significance have the lowest address
1193 location.</dd>
1194
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1195 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1196 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <i>preferred</i> alignments. All sizes are in bits. Specifying
1198 the <i>pref</i> alignment is optional. If omitted, the
1199 preceding <tt>:</tt> should be omitted too.</dd>
1200
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1204
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1205 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1206 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1207 <i>size</i>.</dd>
1208
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1209 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1210 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1211 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1212 (double).</dd>
1213
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1214 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1215 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 <i>size</i>.</dd>
1217
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1218 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1219 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1220 <i>size</i>.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1221</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1222
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1223<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1224 default set of specifications which are then (possibly) overriden by the
1225 specifications in the <tt>datalayout</tt> keyword. The default specifications
1226 are given in this list:</p>
1227
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1228<ul>
1229 <li><tt>E</tt> - big endian</li>
1230 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1231 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1232 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1233 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1234 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1235 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1236 alignment of 64-bits</li>
1237 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1238 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1239 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1240 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1241 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1242 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1243</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244
1245<p>When LLVM is determining the alignment for a given type, it uses the
1246 following rules:</p>
1247
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1248<ol>
1249 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1250 specification is used.</li>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1253 smallest integer type that is larger than the bitwidth of the sought type
1254 is used. If none of the specifications are larger than the bitwidth then
1255 the the largest integer type is used. For example, given the default
1256 specifications above, the i7 type will use the alignment of i8 (next
1257 largest) while both i65 and i256 will use the alignment of i64 (largest
1258 specified).</li>
1259
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1260 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1261 largest vector type that is smaller than the sought vector type will be
1262 used as a fall back. This happens because &lt;128 x double&gt; can be
1263 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1264</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1265
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1266</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1267
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1271</div>
1272
1273<div class="doc_text">
1274
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1275<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1276with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1277is undefined. Pointer values are associated with address ranges
1278according to the following rules:</p>
1279
1280<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1281 <li>A pointer value formed from a
1282 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1283 is associated with the addresses associated with the first operand
1284 of the <tt>getelementptr</tt>.</li>
1285 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1286 range of the variable's storage.</li>
1287 <li>The result value of an allocation instruction is associated with
1288 the address range of the allocated storage.</li>
1289 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1290 no address.</li>
1291 <li>A pointer value formed by an
1292 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1293 address ranges of all pointer values that contribute (directly or
1294 indirectly) to the computation of the pointer's value.</li>
1295 <li>The result value of a
1296 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1297 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1298 <li>An integer constant other than zero or a pointer value returned
1299 from a function not defined within LLVM may be associated with address
1300 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1301 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1302 allocated by mechanisms provided by LLVM.</li>
1303 </ul>
1304
1305<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1306<tt><a href="#i_load">load</a></tt> merely indicates the size and
1307alignment of the memory from which to load, as well as the
1308interpretation of the value. The first operand of a
1309<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1310and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1311
1312<p>Consequently, type-based alias analysis, aka TBAA, aka
1313<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1314LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1315additional information which specialized optimization passes may use
1316to implement type-based alias analysis.</p>
1317
1318</div>
1319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1320<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1321<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1322<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1323
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1324<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1326<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1327 intermediate representation. Being typed enables a number of optimizations
1328 to be performed on the intermediate representation directly, without having
1329 to do extra analyses on the side before the transformation. A strong type
1330 system makes it easier to read the generated code and enables novel analyses
1331 and transformations that are not feasible to perform on normal three address
1332 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1333
1334</div>
1335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1336<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1337<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1338Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1340<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1341
1342<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1343
1344<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1345 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1346 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1347 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1348 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1349 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1350 </tr>
1351 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_floating">floating point</a></td>
1353 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1354 </tr>
1355 <tr>
1356 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1357 <td><a href="#t_integer">integer</a>,
1358 <a href="#t_floating">floating point</a>,
1359 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1360 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1361 <a href="#t_struct">structure</a>,
1362 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_label">label</a>,
1364 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1365 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1366 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1367 <tr>
1368 <td><a href="#t_primitive">primitive</a></td>
1369 <td><a href="#t_label">label</a>,
1370 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1371 <a href="#t_floating">floating point</a>,
1372 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1373 </tr>
1374 <tr>
1375 <td><a href="#t_derived">derived</a></td>
1376 <td><a href="#t_integer">integer</a>,
1377 <a href="#t_array">array</a>,
1378 <a href="#t_function">function</a>,
1379 <a href="#t_pointer">pointer</a>,
1380 <a href="#t_struct">structure</a>,
1381 <a href="#t_pstruct">packed structure</a>,
1382 <a href="#t_vector">vector</a>,
1383 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1384 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1385 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1386 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1387</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1389<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1390 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1391 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1393</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1395<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1396<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1397
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1398<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1399
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1400<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1401 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1402
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1403</div>
1404
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1405<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1406<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1407
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411<p>The integer type is a very simple type that simply specifies an arbitrary
1412 bit width for the integer type desired. Any bit width from 1 bit to
1413 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1414
1415<h5>Syntax:</h5>
1416<pre>
1417 iN
1418</pre>
1419
1420<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1421 value.</p>
1422
1423<h5>Examples:</h5>
1424<table class="layout">
1425 <tr class="layout">
1426 <td class="left"><tt>i1</tt></td>
1427 <td class="left">a single-bit integer.</td>
1428 </tr>
1429 <tr class="layout">
1430 <td class="left"><tt>i32</tt></td>
1431 <td class="left">a 32-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i1942652</tt></td>
1435 <td class="left">a really big integer of over 1 million bits.</td>
1436 </tr>
1437</table>
1438
1439<p>Note that the code generator does not yet support large integer types to be
1440 used as function return types. The specific limit on how large a return type
1441 the code generator can currently handle is target-dependent; currently it's
1442 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1443
1444</div>
1445
1446<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1448
1449<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1450
1451<table>
1452 <tbody>
1453 <tr><th>Type</th><th>Description</th></tr>
1454 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1455 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1456 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1457 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1458 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1459 </tbody>
1460</table>
1461
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1462</div>
1463
1464<!-- _______________________________________________________________________ -->
1465<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1466
1467<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1468
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1469<h5>Overview:</h5>
1470<p>The void type does not represent any value and has no size.</p>
1471
1472<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1473<pre>
1474 void
1475</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1476
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1477</div>
1478
1479<!-- _______________________________________________________________________ -->
1480<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1481
1482<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1483
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1484<h5>Overview:</h5>
1485<p>The label type represents code labels.</p>
1486
1487<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1488<pre>
1489 label
1490</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1491
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492</div>
1493
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1494<!-- _______________________________________________________________________ -->
1495<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1496
1497<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1498
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1499<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1500<p>The metadata type represents embedded metadata. No derived types may be
1501 created from metadata except for <a href="#t_function">function</a>
1502 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1503
1504<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1505<pre>
1506 metadata
1507</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1508
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1509</div>
1510
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1511
1512<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1513<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1514
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1515<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1517<p>The real power in LLVM comes from the derived types in the system. This is
1518 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1519 useful types. Each of these types contain one or more element types which
1520 may be a primitive type, or another derived type. For example, it is
1521 possible to have a two dimensional array, using an array as the element type
1522 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1523
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1524</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1525
1526<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1527<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1529<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1531<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1532<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1533 sequentially in memory. The array type requires a size (number of elements)
1534 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1536<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537<pre>
1538 [&lt;# elements&gt; x &lt;elementtype&gt;]
1539</pre>
1540
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1541<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1542 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1543
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1544<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1545<table class="layout">
1546 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1547 <td class="left"><tt>[40 x i32]</tt></td>
1548 <td class="left">Array of 40 32-bit integer values.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>[41 x i32]</tt></td>
1552 <td class="left">Array of 41 32-bit integer values.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>[4 x i8]</tt></td>
1556 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1557 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1558</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1559<p>Here are some examples of multidimensional arrays:</p>
1560<table class="layout">
1561 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1562 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1563 <td class="left">3x4 array of 32-bit integer values.</td>
1564 </tr>
1565 <tr class="layout">
1566 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1567 <td class="left">12x10 array of single precision floating point values.</td>
1568 </tr>
1569 <tr class="layout">
1570 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1571 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1572 </tr>
1573</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1574
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1575<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1576 length array. Normally, accesses past the end of an array are undefined in
1577 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1578 a special case, however, zero length arrays are recognized to be variable
1579 length. This allows implementation of 'pascal style arrays' with the LLVM
1580 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1581
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1582<p>Note that the code generator does not yet support large aggregate types to be
1583 used as function return types. The specific limit on how large an aggregate
1584 return type the code generator can currently handle is target-dependent, and
1585 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1587</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1592<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1594<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1595<p>The function type can be thought of as a function signature. It consists of
1596 a return type and a list of formal parameter types. The return type of a
1597 function type is a scalar type, a void type, or a struct type. If the return
1598 type is a struct type then all struct elements must be of first class types,
1599 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1601<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1602<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1603 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1604</pre>
1605
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1606<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1607 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1608 which indicates that the function takes a variable number of arguments.
1609 Variable argument functions can access their arguments with
1610 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1611 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1612 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1614<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1615<table class="layout">
1616 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1617 <td class="left"><tt>i32 (i32)</tt></td>
1618 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1619 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1621 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1622 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1623 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1624 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1625 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1626 <tt>float</tt>.
1627 </td>
1628 </tr><tr class="layout">
1629 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1630 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1631 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1632 which returns an integer. This is the signature for <tt>printf</tt> in
1633 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1634 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1635 </tr><tr class="layout">
1636 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1637 <td class="left">A function taking an <tt>i32</tt>, returning a
1638 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1639 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1640 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1641</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1642
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1649
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The structure type is used to represent a collection of data members together
1652 in memory. The packing of the field types is defined to match the ABI of the
1653 underlying processor. The elements of a structure may be any type that has a
1654 size.</p>
1655
1656<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1657 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1658 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1660<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1661<pre>
1662 { &lt;type list&gt; }
1663</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1666<table class="layout">
1667 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1668 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1669 <td class="left">A triple of three <tt>i32</tt> values</td>
1670 </tr><tr class="layout">
1671 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1672 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1673 second element is a <a href="#t_pointer">pointer</a> to a
1674 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1675 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1676 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1677</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1679<p>Note that the code generator does not yet support large aggregate types to be
1680 used as function return types. The specific limit on how large an aggregate
1681 return type the code generator can currently handle is target-dependent, and
1682 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1686<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1687<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1688</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1689
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1690<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1691
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1692<h5>Overview:</h5>
1693<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1694 together in memory. There is no padding between fields. Further, the
1695 alignment of a packed structure is 1 byte. The elements of a packed
1696 structure may be any type that has a size.</p>
1697
1698<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1699 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1700 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1701
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1702<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1703<pre>
1704 &lt; { &lt;type list&gt; } &gt;
1705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1706
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1707<h5>Examples:</h5>
1708<table class="layout">
1709 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1710 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1711 <td class="left">A triple of three <tt>i32</tt> values</td>
1712 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1713 <td class="left">
1714<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1715 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1716 second element is a <a href="#t_pointer">pointer</a> to a
1717 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1718 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1719 </tr>
1720</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1721
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1722</div>
1723
1724<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1726
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1727<div class="doc_text">
1728
1729<h5>Overview:</h5>
1730<p>As in many languages, the pointer type represents a pointer or reference to
1731 another object, which must live in memory. Pointer types may have an optional
1732 address space attribute defining the target-specific numbered address space
1733 where the pointed-to object resides. The default address space is zero.</p>
1734
1735<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1736 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1737
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1738<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1739<pre>
1740 &lt;type&gt; *
1741</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1742
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1743<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1744<table class="layout">
1745 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1746 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1747 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1748 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1749 </tr>
1750 <tr class="layout">
1751 <td class="left"><tt>i32 (i32 *) *</tt></td>
1752 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1753 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1754 <tt>i32</tt>.</td>
1755 </tr>
1756 <tr class="layout">
1757 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1758 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1759 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1760 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1763</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1764
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1765<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1766<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1768<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1769
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1770<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771<p>A vector type is a simple derived type that represents a vector of elements.
1772 Vector types are used when multiple primitive data are operated in parallel
1773 using a single instruction (SIMD). A vector type requires a size (number of
1774 elements) and an underlying primitive data type. Vectors must have a power
1775 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1776 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1777
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1778<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1779<pre>
1780 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1781</pre>
1782
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783<p>The number of elements is a constant integer value; elementtype may be any
1784 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1785
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1786<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787<table class="layout">
1788 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1789 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1790 <td class="left">Vector of 4 32-bit integer values.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1794 <td class="left">Vector of 8 32-bit floating-point values.</td>
1795 </tr>
1796 <tr class="layout">
1797 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1798 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1799 </tr>
1800</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802<p>Note that the code generator does not yet support large vector types to be
1803 used as function return types. The specific limit on how large a vector
1804 return type codegen can currently handle is target-dependent; currently it's
1805 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1806
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1807</div>
1808
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1809<!-- _______________________________________________________________________ -->
1810<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1811<div class="doc_text">
1812
1813<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1814<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1815 corresponds (for example) to the C notion of a forward declared structure
1816 type. In LLVM, opaque types can eventually be resolved to any type (not just
1817 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1818
1819<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1820<pre>
1821 opaque
1822</pre>
1823
1824<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1825<table class="layout">
1826 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1827 <td class="left"><tt>opaque</tt></td>
1828 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1829 </tr>
1830</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1831
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1832</div>
1833
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1834<!-- ======================================================================= -->
1835<div class="doc_subsection">
1836 <a name="t_uprefs">Type Up-references</a>
1837</div>
1838
1839<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1840
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842<p>An "up reference" allows you to refer to a lexically enclosing type without
1843 requiring it to have a name. For instance, a structure declaration may
1844 contain a pointer to any of the types it is lexically a member of. Example
1845 of up references (with their equivalent as named type declarations)
1846 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1847
1848<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1849 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1850 { \2 }* %y = type { %y }*
1851 \1* %z = type %z*
1852</pre>
1853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1854<p>An up reference is needed by the asmprinter for printing out cyclic types
1855 when there is no declared name for a type in the cycle. Because the
1856 asmprinter does not want to print out an infinite type string, it needs a
1857 syntax to handle recursive types that have no names (all names are optional
1858 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1859
1860<h5>Syntax:</h5>
1861<pre>
1862 \&lt;level&gt;
1863</pre>
1864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1865<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1866
1867<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1868<table class="layout">
1869 <tr class="layout">
1870 <td class="left"><tt>\1*</tt></td>
1871 <td class="left">Self-referential pointer.</td>
1872 </tr>
1873 <tr class="layout">
1874 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1875 <td class="left">Recursive structure where the upref refers to the out-most
1876 structure.</td>
1877 </tr>
1878</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1880</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1881
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1882<!-- *********************************************************************** -->
1883<div class="doc_section"> <a name="constants">Constants</a> </div>
1884<!-- *********************************************************************** -->
1885
1886<div class="doc_text">
1887
1888<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1889 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1890
1891</div>
1892
1893<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1894<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1895
1896<div class="doc_text">
1897
1898<dl>
1899 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1900 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1901 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1902
1903 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1904 <dd>Standard integers (such as '4') are constants of
1905 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1906 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1907
1908 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1909 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1911 notation (see below). The assembler requires the exact decimal value of a
1912 floating-point constant. For example, the assembler accepts 1.25 but
1913 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1914 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1915
1916 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1917 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1919</dl>
1920
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1921<p>The one non-intuitive notation for constants is the hexadecimal form of
1922 floating point constants. For example, the form '<tt>double
1923 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1924 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1925 constants are required (and the only time that they are generated by the
1926 disassembler) is when a floating point constant must be emitted but it cannot
1927 be represented as a decimal floating point number in a reasonable number of
1928 digits. For example, NaN's, infinities, and other special values are
1929 represented in their IEEE hexadecimal format so that assembly and disassembly
1930 do not cause any bits to change in the constants.</p>
1931
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1932<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1933 represented using the 16-digit form shown above (which matches the IEEE754
1934 representation for double); float values must, however, be exactly
1935 representable as IEE754 single precision. Hexadecimal format is always used
1936 for long double, and there are three forms of long double. The 80-bit format
1937 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1938 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1939 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1940 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1941 currently supported target uses this format. Long doubles will only work if
1942 they match the long double format on your target. All hexadecimal formats
1943 are big-endian (sign bit at the left).</p>
1944
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1945</div>
1946
1947<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1948<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1949<a name="aggregateconstants"></a> <!-- old anchor -->
1950<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1951</div>
1952
1953<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1954
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1955<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1956 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1957
1958<dl>
1959 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1960 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1961 type definitions (a comma separated list of elements, surrounded by braces
1962 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1963 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1964 Structure constants must have <a href="#t_struct">structure type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1967
1968 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1969 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by square
1971 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1972 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1973 the number and types of elements must match those specified by the
1974 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1976 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1977 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1978 definitions (a comma separated list of elements, surrounded by
1979 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1980 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1981 have <a href="#t_vector">vector type</a>, and the number and types of
1982 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1983
1984 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1985 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986 value to zero of <em>any</em> type, including scalar and aggregate types.
1987 This is often used to avoid having to print large zero initializers
1988 (e.g. for large arrays) and is always exactly equivalent to using explicit
1989 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1990
1991 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1992 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1994 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1995 be interpreted as part of the instruction stream, metadata is a place to
1996 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1997</dl>
1998
1999</div>
2000
2001<!-- ======================================================================= -->
2002<div class="doc_subsection">
2003 <a name="globalconstants">Global Variable and Function Addresses</a>
2004</div>
2005
2006<div class="doc_text">
2007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2008<p>The addresses of <a href="#globalvars">global variables</a>
2009 and <a href="#functionstructure">functions</a> are always implicitly valid
2010 (link-time) constants. These constants are explicitly referenced when
2011 the <a href="#identifiers">identifier for the global</a> is used and always
2012 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2013 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2014
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2015<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2017@X = global i32 17
2018@Y = global i32 42
2019@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2020</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2021</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2022
2023</div>
2024
2025<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2026<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2027<div class="doc_text">
2028
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2029<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2030 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2031 Undefined values may be of any type (other than label or void) and be used
2032 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2033
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2034<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2035 program is well defined no matter what value is used. This gives the
2036 compiler more freedom to optimize. Here are some examples of (potentially
2037 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2039
2040<div class="doc_code">
2041<pre>
2042 %A = add %X, undef
2043 %B = sub %X, undef
2044 %C = xor %X, undef
2045Safe:
2046 %A = undef
2047 %B = undef
2048 %C = undef
2049</pre>
2050</div>
2051
2052<p>This is safe because all of the output bits are affected by the undef bits.
2053Any output bit can have a zero or one depending on the input bits.</p>
2054
2055<div class="doc_code">
2056<pre>
2057 %A = or %X, undef
2058 %B = and %X, undef
2059Safe:
2060 %A = -1
2061 %B = 0
2062Unsafe:
2063 %A = undef
2064 %B = undef
2065</pre>
2066</div>
2067
2068<p>These logical operations have bits that are not always affected by the input.
2069For example, if "%X" has a zero bit, then the output of the 'and' operation will
2070always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2071such, it is unsafe to optimize or assume that the result of the and is undef.
2072However, it is safe to assume that all bits of the undef could be 0, and
2073optimize the and to 0. Likewise, it is safe to assume that all the bits of
2074the undef operand to the or could be set, allowing the or to be folded to
2075-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2076
2077<div class="doc_code">
2078<pre>
2079 %A = select undef, %X, %Y
2080 %B = select undef, 42, %Y
2081 %C = select %X, %Y, undef
2082Safe:
2083 %A = %X (or %Y)
2084 %B = 42 (or %Y)
2085 %C = %Y
2086Unsafe:
2087 %A = undef
2088 %B = undef
2089 %C = undef
2090</pre>
2091</div>
2092
2093<p>This set of examples show that undefined select (and conditional branch)
2094conditions can go "either way" but they have to come from one of the two
2095operands. In the %A example, if %X and %Y were both known to have a clear low
2096bit, then %A would have to have a cleared low bit. However, in the %C example,
2097the optimizer is allowed to assume that the undef operand could be the same as
2098%Y, allowing the whole select to be eliminated.</p>
2099
2100
2101<div class="doc_code">
2102<pre>
2103 %A = xor undef, undef
2104
2105 %B = undef
2106 %C = xor %B, %B
2107
2108 %D = undef
2109 %E = icmp lt %D, 4
2110 %F = icmp gte %D, 4
2111
2112Safe:
2113 %A = undef
2114 %B = undef
2115 %C = undef
2116 %D = undef
2117 %E = undef
2118 %F = undef
2119</pre>
2120</div>
2121
2122<p>This example points out that two undef operands are not necessarily the same.
2123This can be surprising to people (and also matches C semantics) where they
2124assume that "X^X" is always zero, even if X is undef. This isn't true for a
2125number of reasons, but the short answer is that an undef "variable" can
2126arbitrarily change its value over its "live range". This is true because the
2127"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2128logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2129so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2130to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2131would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2132
2133<div class="doc_code">
2134<pre>
2135 %A = fdiv undef, %X
2136 %B = fdiv %X, undef
2137Safe:
2138 %A = undef
2139b: unreachable
2140</pre>
2141</div>
2142
2143<p>These examples show the crucial difference between an <em>undefined
2144value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2145allowed to have an arbitrary bit-pattern. This means that the %A operation
2146can be constant folded to undef because the undef could be an SNaN, and fdiv is
2147not (currently) defined on SNaN's. However, in the second example, we can make
2148a more aggressive assumption: because the undef is allowed to be an arbitrary
2149value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner8e371aa2009-09-08 19:45:34 +0000[diff] [blame]2150has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2151does not execute at all. This allows us to delete the divide and all code after
2152it: since the undefined operation "can't happen", the optimizer can assume that
2153it occurs in dead code.
2154</p>
2155
2156<div class="doc_code">
2157<pre>
2158a: store undef -> %X
2159b: store %X -> undef
2160Safe:
2161a: &lt;deleted&gt;
2162b: unreachable
2163</pre>
2164</div>
2165
2166<p>These examples reiterate the fdiv example: a store "of" an undefined value
2167can be assumed to not have any effect: we can assume that the value is
2168overwritten with bits that happen to match what was already there. However, a
2169store "to" an undefined location could clobber arbitrary memory, therefore, it
2170has undefined behavior.</p>
2171
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2172</div>
2173
2174<!-- ======================================================================= -->
2175<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2176</div>
2177
2178<div class="doc_text">
2179
2180<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181 to be used as constants. Constant expressions may be of
2182 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2183 operation that does not have side effects (e.g. load and call are not
2184 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2185
2186<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2187 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2188 <dd>Truncate a constant to another type. The bit size of CST must be larger
2189 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2190
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2191 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2192 <dd>Zero extend a constant to another type. The bit size of CST must be
2193 smaller or equal to the bit size of TYPE. Both types must be
2194 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2195
2196 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2197 <dd>Sign extend a constant to another type. The bit size of CST must be
2198 smaller or equal to the bit size of TYPE. Both types must be
2199 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2200
2201 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2202 <dd>Truncate a floating point constant to another floating point type. The
2203 size of CST must be larger than the size of TYPE. Both types must be
2204 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2205
2206 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2207 <dd>Floating point extend a constant to another type. The size of CST must be
2208 smaller or equal to the size of TYPE. Both types must be floating
2209 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2210
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2211 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2212 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2213 constant. TYPE must be a scalar or vector integer type. CST must be of
2214 scalar or vector floating point type. Both CST and TYPE must be scalars,
2215 or vectors of the same number of elements. If the value won't fit in the
2216 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2217
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2218 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2219 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2220 constant. TYPE must be a scalar or vector integer type. CST must be of
2221 scalar or vector floating point type. Both CST and TYPE must be scalars,
2222 or vectors of the same number of elements. If the value won't fit in the
2223 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2224
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2225 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2226 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2227 constant. TYPE must be a scalar or vector floating point type. CST must be
2228 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2229 vectors of the same number of elements. If the value won't fit in the
2230 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2231
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2232 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2233 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2234 constant. TYPE must be a scalar or vector floating point type. CST must be
2235 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2236 vectors of the same number of elements. If the value won't fit in the
2237 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2238
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2239 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2240 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2241 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2242 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2243 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2244
2245 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2246 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2247 type. CST must be of integer type. The CST value is zero extended,
2248 truncated, or unchanged to make it fit in a pointer size. This one is
2249 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2250
2251 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2252 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2253 are the same as those for the <a href="#i_bitcast">bitcast
2254 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2255
2256 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2257 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2258 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2259 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2260 instruction, the index list may have zero or more indexes, which are
2261 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2262
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2263 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2264 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2265
2266 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2267 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2268
2269 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2270 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2271
2272 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2273 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2274 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2275
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2276 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2277 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2278 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2279
2280 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2281 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2282 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2283
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2284 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2285 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2286 be any of the <a href="#binaryops">binary</a>
2287 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2288 on operands are the same as those for the corresponding instruction
2289 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2290</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2291
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2293
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2294<!-- ======================================================================= -->
2295<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2296</div>
2297
2298<div class="doc_text">
2299
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2300<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2301 stream without affecting the behaviour of the program. There are two
2302 metadata primitives, strings and nodes. All metadata has the
2303 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2304 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2305
2306<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2307 any character by escaping non-printable characters with "\xx" where "xx" is
2308 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2309
2310<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2311 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2313 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2314
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2315<p>A metadata node will attempt to track changes to the values it holds. In the
2316 event that a value is deleted, it will be replaced with a typeless
2317 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2318
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2319<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2320 the program that isn't available in the instructions, or that isn't easily
2321 computable. Similarly, the code generator may expect a certain metadata
2322 format to be used to express debugging information.</p>
2323
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2324</div>
2325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2326<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2327<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2328<!-- *********************************************************************** -->
2329
2330<!-- ======================================================================= -->
2331<div class="doc_subsection">
2332<a name="inlineasm">Inline Assembler Expressions</a>
2333</div>
2334
2335<div class="doc_text">
2336
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2337<p>LLVM supports inline assembler expressions (as opposed
2338 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2339 a special value. This value represents the inline assembler as a string
2340 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame^]2341 as a string), a flag that indicates whether or not the inline asm
2342 expression has side effects, and a flag indicating whether the asm came
2343 originally from an asm block. An example inline assembler
2344 expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2345
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2346<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2347<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2348i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2349</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2350</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2352<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2353 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2354 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2355
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2356<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2357<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2358%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]2359</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2360</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2362<p>Inline asms with side effects not visible in the constraint list must be
2363 marked as having side effects. This is done through the use of the
2364 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2365
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2366<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2367<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2368call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2369</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2370</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2371
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame^]2372<p>Inline asms derived from asm blocks are similarly marked with the
2373 '<tt>msasm</tt>' keyword:</p>
2374
2375<div class="doc_code">
2376<pre>
2377call void asm msasm "eieio", ""()
2378</pre>
2379</div>
2380
2381<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2382 first.</p>
2383
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2384<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2385 documented here. Constraints on what can be done (e.g. duplication, moving,
2386 etc need to be documented). This is probably best done by reference to
2387 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2388
2389</div>
2390
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2391
2392<!-- *********************************************************************** -->
2393<div class="doc_section">
2394 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2395</div>
2396<!-- *********************************************************************** -->
2397
2398<p>LLVM has a number of "magic" global variables that contain data that affect
2399code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2400of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2401section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2402by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2403
2404<!-- ======================================================================= -->
2405<div class="doc_subsection">
2406<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2407</div>
2408
2409<div class="doc_text">
2410
2411<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2412href="#linkage_appending">appending linkage</a>. This array contains a list of
2413pointers to global variables and functions which may optionally have a pointer
2414cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2415
2416<pre>
2417 @X = global i8 4
2418 @Y = global i32 123
2419
2420 @llvm.used = appending global [2 x i8*] [
2421 i8* @X,
2422 i8* bitcast (i32* @Y to i8*)
2423 ], section "llvm.metadata"
2424</pre>
2425
2426<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2427compiler, assembler, and linker are required to treat the symbol as if there is
2428a reference to the global that it cannot see. For example, if a variable has
2429internal linkage and no references other than that from the <tt>@llvm.used</tt>
2430list, it cannot be deleted. This is commonly used to represent references from
2431inline asms and other things the compiler cannot "see", and corresponds to
2432"attribute((used))" in GNU C.</p>
2433
2434<p>On some targets, the code generator must emit a directive to the assembler or
2435object file to prevent the assembler and linker from molesting the symbol.</p>
2436
2437</div>
2438
2439<!-- ======================================================================= -->
2440<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2441<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2442</div>
2443
2444<div class="doc_text">
2445
2446<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2447<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2448touching the symbol. On targets that support it, this allows an intelligent
2449linker to optimize references to the symbol without being impeded as it would be
2450by <tt>@llvm.used</tt>.</p>
2451
2452<p>This is a rare construct that should only be used in rare circumstances, and
2453should not be exposed to source languages.</p>
2454
2455</div>
2456
2457<!-- ======================================================================= -->
2458<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2459<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2460</div>
2461
2462<div class="doc_text">
2463
2464<p>TODO: Describe this.</p>
2465
2466</div>
2467
2468<!-- ======================================================================= -->
2469<div class="doc_subsection">
2470<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2471</div>
2472
2473<div class="doc_text">
2474
2475<p>TODO: Describe this.</p>
2476
2477</div>
2478
2479
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2480<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2481<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2482<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2483
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2484<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2486<p>The LLVM instruction set consists of several different classifications of
2487 instructions: <a href="#terminators">terminator
2488 instructions</a>, <a href="#binaryops">binary instructions</a>,
2489 <a href="#bitwiseops">bitwise binary instructions</a>,
2490 <a href="#memoryops">memory instructions</a>, and
2491 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2492
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2493</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2494
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2495<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2496<div class="doc_subsection"> <a name="terminators">Terminator
2497Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2498
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2499<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2500
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2502 in a program ends with a "Terminator" instruction, which indicates which
2503 block should be executed after the current block is finished. These
2504 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2505 control flow, not values (the one exception being the
2506 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2507
2508<p>There are six different terminator instructions: the
2509 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2510 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2511 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2512 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2513 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2514 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2515
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2516</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2517
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2518<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2519<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2520Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2521
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2522<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2525<pre>
2526 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]2527 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2528</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2530<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2531<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2532 a value) from a function back to the caller.</p>
2533
2534<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2535 value and then causes control flow, and one that just causes control flow to
2536 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2538<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2539<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2540 return value. The type of the return value must be a
2541 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2542
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2543<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2544 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2545 value or a return value with a type that does not match its type, or if it
2546 has a void return type and contains a '<tt>ret</tt>' instruction with a
2547 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2548
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2549<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2550<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2551 the calling function's context. If the caller is a
2552 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2553 instruction after the call. If the caller was an
2554 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2555 the beginning of the "normal" destination block. If the instruction returns
2556 a value, that value shall set the call or invoke instruction's return
2557 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2559<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2560<pre>
2561 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2562 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2563 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2564</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2565
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2566<p>Note that the code generator does not yet fully support large
2567 return values. The specific sizes that are currently supported are
2568 dependent on the target. For integers, on 32-bit targets the limit
2569 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2570 For aggregate types, the current limits are dependent on the element
2571 types; for example targets are often limited to 2 total integer
2572 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2573
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2574</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2576<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2577
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2578<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2579
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2580<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2581<pre>
2582 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]2583</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2584
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2585<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2586<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2587 different basic block in the current function. There are two forms of this
2588 instruction, corresponding to a conditional branch and an unconditional
2589 branch.</p>
2590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2591<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2592<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2593 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2594 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2595 target.</p>
2596
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2597<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2598<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2599 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2600 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2601 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2602
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2603<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2604<pre>
2605Test:
2606 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2607 br i1 %cond, label %IfEqual, label %IfUnequal
2608IfEqual:
2609 <a href="#i_ret">ret</a> i32 1
2610IfUnequal:
2611 <a href="#i_ret">ret</a> i32 0
2612</pre>
2613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2614</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2615
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2616<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2617<div class="doc_subsubsection">
2618 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2619</div>
2620
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2621<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2622
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2623<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2624<pre>
2625 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2626</pre>
2627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2628<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2629<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2630 several different places. It is a generalization of the '<tt>br</tt>'
2631 instruction, allowing a branch to occur to one of many possible
2632 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2633
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2634<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2635<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2636 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2637 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2638 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2639
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2640<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2641<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2642 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2643 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2644 transferred to the corresponding destination; otherwise, control flow is
2645 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2646
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2647<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2648<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2649 <tt>switch</tt> instruction, this instruction may be code generated in
2650 different ways. For example, it could be generated as a series of chained
2651 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2652
2653<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2654<pre>
2655 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2656 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2657 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2658
2659 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2660 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2661
2662 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2663 switch i32 %val, label %otherwise [ i32 0, label %onzero
2664 i32 1, label %onone
2665 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2666</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2668</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2670<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2671<div class="doc_subsubsection">
2672 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2673</div>
2674
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2675<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2676
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2677<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2678<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2679 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]2680 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2681</pre>
2682
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2683<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2684<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2685 function, with the possibility of control flow transfer to either the
2686 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2687 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2688 control flow will return to the "normal" label. If the callee (or any
2689 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2690 instruction, control is interrupted and continued at the dynamically nearest
2691 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2692
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2693<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2694<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2696<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2697 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2698 convention</a> the call should use. If none is specified, the call
2699 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2700
2701 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2702 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2703 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2704
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2705 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2706 function value being invoked. In most cases, this is a direct function
2707 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2708 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2709
2710 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2711 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2712
2713 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2714 signature argument types. If the function signature indicates the
2715 function accepts a variable number of arguments, the extra arguments can
2716 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2717
2718 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2719 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2720
2721 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2722 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2723
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2724 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2725 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2726 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2727</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2728
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2729<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2730<p>This instruction is designed to operate as a standard
2731 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2732 primary difference is that it establishes an association with a label, which
2733 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2734
2735<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2736 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2737 exception. Additionally, this is important for implementation of
2738 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2739
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2740<p>For the purposes of the SSA form, the definition of the value returned by the
2741 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2742 block to the "normal" label. If the callee unwinds then no return value is
2743 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2744
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2745<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2746<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2747 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2748 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2749 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2750 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2751</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2753</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2754
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2755<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2756
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2757<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2758Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2759
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2760<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2761
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2762<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2763<pre>
2764 unwind
2765</pre>
2766
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2767<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2768<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2769 at the first callee in the dynamic call stack which used
2770 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2771 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2772
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2773<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2774<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2775 immediately halt. The dynamic call stack is then searched for the
2776 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2777 Once found, execution continues at the "exceptional" destination block
2778 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2779 instruction in the dynamic call chain, undefined behavior results.</p>
2780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2781</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2782
2783<!-- _______________________________________________________________________ -->
2784
2785<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2786Instruction</a> </div>
2787
2788<div class="doc_text">
2789
2790<h5>Syntax:</h5>
2791<pre>
2792 unreachable
2793</pre>
2794
2795<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2796<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2797 instruction is used to inform the optimizer that a particular portion of the
2798 code is not reachable. This can be used to indicate that the code after a
2799 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2800
2801<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2802<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2803
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2804</div>
2805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2806<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2807<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2808
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2809<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2810
2811<p>Binary operators are used to do most of the computation in a program. They
2812 require two operands of the same type, execute an operation on them, and
2813 produce a single value. The operands might represent multiple data, as is
2814 the case with the <a href="#t_vector">vector</a> data type. The result value
2815 has the same type as its operands.</p>
2816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2817<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2818
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2819</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2820
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2821<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2822<div class="doc_subsubsection">
2823 <a name="i_add">'<tt>add</tt>' Instruction</a>
2824</div>
2825
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2826<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2828<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2829<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2830 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]2831 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2832 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2833 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2834</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2837<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2840<p>The two arguments to the '<tt>add</tt>' instruction must
2841 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2842 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2844<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2845<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2846
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2847<p>If the sum has unsigned overflow, the result returned is the mathematical
2848 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2850<p>Because LLVM integers use a two's complement representation, this instruction
2851 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2852
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2853<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2854 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2855 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2856 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2858<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2859<pre>
2860 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2861</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2862
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2863</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2864
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2865<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2866<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2867 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2868</div>
2869
2870<div class="doc_text">
2871
2872<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2873<pre>
2874 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2875</pre>
2876
2877<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2878<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2879
2880<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2881<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2883 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2884
2885<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2886<p>The value produced is the floating point sum of the two operands.</p>
2887
2888<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2889<pre>
2890 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2891</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2892
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2893</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2895<!-- _______________________________________________________________________ -->
2896<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2897 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2898</div>
2899
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2900<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2902<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2903<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2904 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]2905 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2906 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2907 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2908</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2910<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2911<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2912 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2913
2914<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2915 '<tt>neg</tt>' instruction present in most other intermediate
2916 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<p>The two arguments to the '<tt>sub</tt>' instruction must
2920 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2921 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2924<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2925
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2926<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2927 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2928 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2929
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2930<p>Because LLVM integers use a two's complement representation, this instruction
2931 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2932
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2933<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2934 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2935 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2936 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2937
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2938<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2939<pre>
2940 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2941 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2942</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2943
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2944</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2946<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2947<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2948 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2949</div>
2950
2951<div class="doc_text">
2952
2953<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2954<pre>
2955 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2956</pre>
2957
2958<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2959<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2960 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2961
2962<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2963 '<tt>fneg</tt>' instruction present in most other intermediate
2964 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2965
2966<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2967<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2968 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2969 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2970
2971<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2972<p>The value produced is the floating point difference of the two operands.</p>
2973
2974<h5>Example:</h5>
2975<pre>
2976 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2977 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2978</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2979
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2980</div>
2981
2982<!-- _______________________________________________________________________ -->
2983<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2984 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2985</div>
2986
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2987<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2989<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2990<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2991 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]2992 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2993 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2994 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2995</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2996
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2997<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2998<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2999
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3000<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3001<p>The two arguments to the '<tt>mul</tt>' instruction must
3002 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3003 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3004
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3005<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3006<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3008<p>If the result of the multiplication has unsigned overflow, the result
3009 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3010 width of the result.</p>
3011
3012<p>Because LLVM integers use a two's complement representation, and the result
3013 is the same width as the operands, this instruction returns the correct
3014 result for both signed and unsigned integers. If a full product
3015 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3016 be sign-extended or zero-extended as appropriate to the width of the full
3017 product.</p>
3018
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3019<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3020 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3021 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3022 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3023
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3024<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3025<pre>
3026 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3027</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3028
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3029</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3030
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3031<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3032<div class="doc_subsubsection">
3033 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3034</div>
3035
3036<div class="doc_text">
3037
3038<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3039<pre>
3040 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3041</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3042
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3043<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3044<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3045
3046<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3047<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3048 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3049 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3050
3051<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3052<p>The value produced is the floating point product of the two operands.</p>
3053
3054<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3055<pre>
3056 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3057</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3058
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3059</div>
3060
3061<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3062<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3063</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3064
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3065<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3066
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3067<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3068<pre>
3069 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3070</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3071
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3072<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3073<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3074
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3075<h5>Arguments:</h5>
3076<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3077 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3078 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3079
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3080<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3081<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3082
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3083<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3084 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3085
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3086<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3087
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3088<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089<pre>
3090 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3091</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3092
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3093</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3094
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3095<!-- _______________________________________________________________________ -->
3096<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3097</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3099<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3100
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3101<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3102<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3103 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3104 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3105</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3106
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3107<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3108<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3109
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3110<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3111<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3113 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3114
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3115<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3116<p>The value produced is the signed integer quotient of the two operands rounded
3117 towards zero.</p>
3118
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3119<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3120 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3121
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3122<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123 undefined behavior; this is a rare case, but can occur, for example, by doing
3124 a 32-bit division of -2147483648 by -1.</p>
3125
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3126<p>If the <tt>exact</tt> keyword is present, the result value of the
3127 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3128 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3129
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3130<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3131<pre>
3132 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3133</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3134
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3135</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3136
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3137<!-- _______________________________________________________________________ -->
3138<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3139Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3140
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3141<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3142
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3143<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3144<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3145 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3146</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3148<h5>Overview:</h5>
3149<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3150
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3151<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3152<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3153 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3154 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3155
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3156<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3157<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3158
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3159<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3160<pre>
3161 &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]3162</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3163
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3164</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3165
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3166<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3167<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3168</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3170<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3171
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3172<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173<pre>
3174 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3175</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3176
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3177<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3178<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3179 division of its two arguments.</p>
3180
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3181<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3182<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3183 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3184 values. Both arguments must have identical types.</p>
3185
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3186<h5>Semantics:</h5>
3187<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3188 This instruction always performs an unsigned division to get the
3189 remainder.</p>
3190
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3191<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3193
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3194<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3195
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3196<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197<pre>
3198 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3199</pre>
3200
3201</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3203<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3204<div class="doc_subsubsection">
3205 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3206</div>
3207
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3208<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3209
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3210<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3211<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3212 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3213</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3214
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3215<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3216<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3217 division of its two operands. This instruction can also take
3218 <a href="#t_vector">vector</a> versions of the values in which case the
3219 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3220
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3221<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3222<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3223 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3224 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3225
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3226<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3227<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3228 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3229 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3230 a value. For more information about the difference,
3231 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3232 Math Forum</a>. For a table of how this is implemented in various languages,
3233 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3234 Wikipedia: modulo operation</a>.</p>
3235
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3236<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3238
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3239<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240 Overflow also leads to undefined behavior; this is a rare case, but can
3241 occur, for example, by taking the remainder of a 32-bit division of
3242 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3243 lets srem be implemented using instructions that return both the result of
3244 the division and the remainder.)</p>
3245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3246<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247<pre>
3248 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3249</pre>
3250
3251</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3253<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254<div class="doc_subsubsection">
3255 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3256
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3257<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3258
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3259<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3260<pre>
3261 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3262</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3263
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3264<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3265<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3266 its two operands.</p>
3267
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3268<h5>Arguments:</h5>
3269<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3270 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3271 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3272
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3273<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3274<p>This instruction returns the <i>remainder</i> of a division. The remainder
3275 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3276
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3277<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3278<pre>
3279 &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]3280</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3281
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3282</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3283
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3284<!-- ======================================================================= -->
3285<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3286Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3287
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3288<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3289
3290<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3291 program. They are generally very efficient instructions and can commonly be
3292 strength reduced from other instructions. They require two operands of the
3293 same type, execute an operation on them, and produce a single value. The
3294 resulting value is the same type as its operands.</p>
3295
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3296</div>
3297
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3298<!-- _______________________________________________________________________ -->
3299<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3300Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3301
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3302<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3303
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3304<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305<pre>
3306 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3307</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3308
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3309<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3311 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3312
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3313<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3315 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3316 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3317
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3318<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3320 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3321 is (statically or dynamically) negative or equal to or larger than the number
3322 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3323 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3324 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3326<h5>Example:</h5>
3327<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3328 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3329 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3330 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3331 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3332 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3333</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3334
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3335</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3336
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3337<!-- _______________________________________________________________________ -->
3338<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3339Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3340
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3341<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3342
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3343<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344<pre>
3345 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3346</pre>
3347
3348<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3350 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3351
3352<h5>Arguments:</h5>
3353<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3354 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3355 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3356
3357<h5>Semantics:</h5>
3358<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359 significant bits of the result will be filled with zero bits after the shift.
3360 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3361 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3362 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3363 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3364
3365<h5>Example:</h5>
3366<pre>
3367 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3368 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3369 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3370 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3371 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3372 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3373</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3375</div>
3376
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3377<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3378<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3379Instruction</a> </div>
3380<div class="doc_text">
3381
3382<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383<pre>
3384 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3385</pre>
3386
3387<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3388<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3389 operand shifted to the right a specified number of bits with sign
3390 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3391
3392<h5>Arguments:</h5>
3393<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3394 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3395 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3396
3397<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398<p>This instruction always performs an arithmetic shift right operation, The
3399 most significant bits of the result will be filled with the sign bit
3400 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3401 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3402 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3403 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3404
3405<h5>Example:</h5>
3406<pre>
3407 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3408 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3409 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3410 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3411 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3412 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3413</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3414
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3415</div>
3416
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3417<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3418<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3419Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3421<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3422
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3423<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3424<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3425 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3426</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3427
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3428<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3429<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3430 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3432<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3433<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3435 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3436
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3437<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3438<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3440<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3441 <tbody>
3442 <tr>
3443 <td>In0</td>
3444 <td>In1</td>
3445 <td>Out</td>
3446 </tr>
3447 <tr>
3448 <td>0</td>
3449 <td>0</td>
3450 <td>0</td>
3451 </tr>
3452 <tr>
3453 <td>0</td>
3454 <td>1</td>
3455 <td>0</td>
3456 </tr>
3457 <tr>
3458 <td>1</td>
3459 <td>0</td>
3460 <td>0</td>
3461 </tr>
3462 <tr>
3463 <td>1</td>
3464 <td>1</td>
3465 <td>1</td>
3466 </tr>
3467 </tbody>
3468</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3471<pre>
3472 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3473 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3474 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3476</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3477<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3478<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3479
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480<div class="doc_text">
3481
3482<h5>Syntax:</h5>
3483<pre>
3484 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3485</pre>
3486
3487<h5>Overview:</h5>
3488<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3489 two operands.</p>
3490
3491<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3492<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3493 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3494 values. Both arguments must have identical types.</p>
3495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3496<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3497<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3499<table border="1" cellspacing="0" cellpadding="4">
3500 <tbody>
3501 <tr>
3502 <td>In0</td>
3503 <td>In1</td>
3504 <td>Out</td>
3505 </tr>
3506 <tr>
3507 <td>0</td>
3508 <td>0</td>
3509 <td>0</td>
3510 </tr>
3511 <tr>
3512 <td>0</td>
3513 <td>1</td>
3514 <td>1</td>
3515 </tr>
3516 <tr>
3517 <td>1</td>
3518 <td>0</td>
3519 <td>1</td>
3520 </tr>
3521 <tr>
3522 <td>1</td>
3523 <td>1</td>
3524 <td>1</td>
3525 </tr>
3526 </tbody>
3527</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3529<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530<pre>
3531 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3532 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3533 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3534</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3536</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3538<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3539<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3540Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3542<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3543
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3544<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545<pre>
3546 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3547</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3549<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3551 its two operands. The <tt>xor</tt> is used to implement the "one's
3552 complement" operation, which is the "~" operator in C.</p>
3553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3554<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3555<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3557 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3559<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3562<table border="1" cellspacing="0" cellpadding="4">
3563 <tbody>
3564 <tr>
3565 <td>In0</td>
3566 <td>In1</td>
3567 <td>Out</td>
3568 </tr>
3569 <tr>
3570 <td>0</td>
3571 <td>0</td>
3572 <td>0</td>
3573 </tr>
3574 <tr>
3575 <td>0</td>
3576 <td>1</td>
3577 <td>1</td>
3578 </tr>
3579 <tr>
3580 <td>1</td>
3581 <td>0</td>
3582 <td>1</td>
3583 </tr>
3584 <tr>
3585 <td>1</td>
3586 <td>1</td>
3587 <td>0</td>
3588 </tr>
3589 </tbody>
3590</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3592<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3593<pre>
3594 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3595 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3596 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3597 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3598</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3599
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3600</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3601
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3602<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3603<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3604 <a name="vectorops">Vector Operations</a>
3605</div>
3606
3607<div class="doc_text">
3608
3609<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3610 target-independent manner. These instructions cover the element-access and
3611 vector-specific operations needed to process vectors effectively. While LLVM
3612 does directly support these vector operations, many sophisticated algorithms
3613 will want to use target-specific intrinsics to take full advantage of a
3614 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3615
3616</div>
3617
3618<!-- _______________________________________________________________________ -->
3619<div class="doc_subsubsection">
3620 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3621</div>
3622
3623<div class="doc_text">
3624
3625<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3626<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3627 &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]3628</pre>
3629
3630<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3632 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3633
3634
3635<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3637 of <a href="#t_vector">vector</a> type. The second operand is an index
3638 indicating the position from which to extract the element. The index may be
3639 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3640
3641<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The result is a scalar of the same type as the element type of
3643 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3644 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3645 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3646
3647<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3648<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3649 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3650</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3651
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3652</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3653
3654<!-- _______________________________________________________________________ -->
3655<div class="doc_subsubsection">
3656 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3657</div>
3658
3659<div class="doc_text">
3660
3661<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3662<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3663 &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]3664</pre>
3665
3666<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3668 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3669
3670<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3671<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3672 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3673 whose type must equal the element type of the first operand. The third
3674 operand is an index indicating the position at which to insert the value.
3675 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3676
3677<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3679 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3680 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3681 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3682
3683<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3684<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3685 %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]3686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3687
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3688</div>
3689
3690<!-- _______________________________________________________________________ -->
3691<div class="doc_subsubsection">
3692 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3693</div>
3694
3695<div class="doc_text">
3696
3697<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3698<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3699 &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;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3700</pre>
3701
3702<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3703<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3704 from two input vectors, returning a vector with the same element type as the
3705 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3706
3707<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3708<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3709 with types that match each other. The third argument is a shuffle mask whose
3710 element type is always 'i32'. The result of the instruction is a vector
3711 whose length is the same as the shuffle mask and whose element type is the
3712 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3713
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714<p>The shuffle mask operand is required to be a constant vector with either
3715 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3716
3717<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3718<p>The elements of the two input vectors are numbered from left to right across
3719 both of the vectors. The shuffle mask operand specifies, for each element of
3720 the result vector, which element of the two input vectors the result element
3721 gets. The element selector may be undef (meaning "don't care") and the
3722 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3723
3724<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3725<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3726 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3727 &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]3728 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3729 &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.
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3730 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3731 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3732 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3733 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3734</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3735
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3737
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3738<!-- ======================================================================= -->
3739<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3740 <a name="aggregateops">Aggregate Operations</a>
3741</div>
3742
3743<div class="doc_text">
3744
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3745<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3746
3747</div>
3748
3749<!-- _______________________________________________________________________ -->
3750<div class="doc_subsubsection">
3751 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3752</div>
3753
3754<div class="doc_text">
3755
3756<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3757<pre>
3758 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3759</pre>
3760
3761<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3763 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3764
3765<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3767 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3768 operands are constant indices to specify which value to extract in a similar
3769 manner as indices in a
3770 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3771
3772<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3773<p>The result is the value at the position in the aggregate specified by the
3774 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3775
3776<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3777<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3778 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3779</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3780
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3781</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3782
3783<!-- _______________________________________________________________________ -->
3784<div class="doc_subsubsection">
3785 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3786</div>
3787
3788<div class="doc_text">
3789
3790<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3791<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3792 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3793</pre>
3794
3795<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3796<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3797 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3798
3799
3800<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3801<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3802 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3803 second operand is a first-class value to insert. The following operands are
3804 constant indices indicating the position at which to insert the value in a
3805 similar manner as indices in a
3806 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3807 value to insert must have the same type as the value identified by the
3808 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3809
3810<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3811<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3812 that of <tt>val</tt> except that the value at the position specified by the
3813 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3814
3815<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3816<pre>
Dan Gohman52bb2db2008-06-23 15:26:37 +0000[diff] [blame]3817 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3818</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3819
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3820</div>
3821
3822
3823<!-- ======================================================================= -->
3824<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3825 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3826</div>
3827
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3828<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3830<p>A key design point of an SSA-based representation is how it represents
3831 memory. In LLVM, no memory locations are in SSA form, which makes things
3832 very simple. This section describes how to read, write, allocate, and free
3833 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3834
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3835</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3836
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3837<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3838<div class="doc_subsubsection">
3839 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3840</div>
3841
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3842<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3844<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3845<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3846 &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]3847</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3849<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3851 returns a pointer to it. The object is always allocated in the generic
3852 address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3854<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3855<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3856 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3857 system and returns a pointer of the appropriate type to the program. If
3858 "NumElements" is specified, it is the number of elements allocated, otherwise
3859 "NumElements" is defaulted to be one. If a constant alignment is specified,
3860 the value result of the allocation is guaranteed to be aligned to at least
3861 that boundary. If not specified, or if zero, the target can choose to align
3862 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3863
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3864<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3865
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3866<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3867<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3868 pointer is returned. The result of a zero byte allocation is undefined. The
3869 result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3870
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3871<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3872<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3873 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3874
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3875 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3876 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3877 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3878 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3879 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3880</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3881
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3883
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3884</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3886<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3887<div class="doc_subsubsection">
3888 <a name="i_free">'<tt>free</tt>' Instruction</a>
3889</div>
3890
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3891<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3893<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3894<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3895 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3896</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3898<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3899<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3900 to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3902<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3904 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907<p>Access to the memory pointed to by the pointer is no longer defined after
3908 this instruction executes. If the pointer is null, the operation is a
3909 noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3911<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3912<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3913 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3914 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3915</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3917</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3918
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3919<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3920<div class="doc_subsubsection">
3921 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3922</div>
3923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3924<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3927<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3928 &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]3929</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3930
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3931<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3932<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933 currently executing function, to be automatically released when this function
3934 returns to its caller. The object is always allocated in the generic address
3935 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938<p>The '<tt>alloca</tt>' instruction
3939 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3940 runtime stack, returning a pointer of the appropriate type to the program.
3941 If "NumElements" is specified, it is the number of elements allocated,
3942 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3943 specified, the value result of the allocation is guaranteed to be aligned to
3944 at least that boundary. If not specified, or if zero, the target can choose
3945 to align the allocation on any convenient boundary compatible with the
3946 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3947
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3948<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3949
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3950<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3951<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3953 memory is automatically released when the function returns. The
3954 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3955 variables that must have an address available. When the function returns
3956 (either with the <tt><a href="#i_ret">ret</a></tt>
3957 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3958 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3960<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3961<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3962 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3963 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3964 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3965 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3966</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3968</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3969
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3970<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3971<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3972Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3973
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3974<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3975
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3976<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977<pre>
3978 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3979 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3980</pre>
3981
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3982<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3983<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3984
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3985<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3986<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3987 from which to load. The pointer must point to
3988 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3989 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3990 number or order of execution of this <tt>load</tt> with other
3991 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3992 instructions. </p>
3993
3994<p>The optional constant "align" argument specifies the alignment of the
3995 operation (that is, the alignment of the memory address). A value of 0 or an
3996 omitted "align" argument means that the operation has the preferential
3997 alignment for the target. It is the responsibility of the code emitter to
3998 ensure that the alignment information is correct. Overestimating the
3999 alignment results in an undefined behavior. Underestimating the alignment may
4000 produce less efficient code. An alignment of 1 is always safe.</p>
4001
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4002<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003<p>The location of memory pointed to is loaded. If the value being loaded is of
4004 scalar type then the number of bytes read does not exceed the minimum number
4005 of bytes needed to hold all bits of the type. For example, loading an
4006 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4007 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4008 is undefined if the value was not originally written using a store of the
4009 same type.</p>
4010
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4011<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012<pre>
4013 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4014 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4015 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4016</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4017
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4018</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4020<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4021<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4022Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4024<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4025
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4026<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<pre>
4028 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]4029 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]4030</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4032<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4033<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4034
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4035<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4036<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4037 and an address at which to store it. The type of the
4038 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4039 the <a href="#t_firstclass">first class</a> type of the
4040 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4041 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4042 or order of execution of this <tt>store</tt> with other
4043 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4044 instructions.</p>
4045
4046<p>The optional constant "align" argument specifies the alignment of the
4047 operation (that is, the alignment of the memory address). A value of 0 or an
4048 omitted "align" argument means that the operation has the preferential
4049 alignment for the target. It is the responsibility of the code emitter to
4050 ensure that the alignment information is correct. Overestimating the
4051 alignment results in an undefined behavior. Underestimating the alignment may
4052 produce less efficient code. An alignment of 1 is always safe.</p>
4053
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4054<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4056 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4057 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4058 does not exceed the minimum number of bytes needed to hold all bits of the
4059 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4060 writing a value of a type like <tt>i20</tt> with a size that is not an
4061 integral number of bytes, it is unspecified what happens to the extra bits
4062 that do not belong to the type, but they will typically be overwritten.</p>
4063
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4064<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<pre>
4066 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4067 store i32 3, i32* %ptr <i>; yields {void}</i>
4068 %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]4069</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4071</div>
4072
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4073<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4074<div class="doc_subsubsection">
4075 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4076</div>
4077
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4078<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4079
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4080<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4081<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4082 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4083 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4084</pre>
4085
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4086<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4087<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4088 subelement of an aggregate data structure. It performs address calculation
4089 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4090
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4091<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4092<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4093 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4094 elements of the aggregate object are indexed. The interpretation of each
4095 index is dependent on the type being indexed into. The first index always
4096 indexes the pointer value given as the first argument, the second index
4097 indexes a value of the type pointed to (not necessarily the value directly
4098 pointed to, since the first index can be non-zero), etc. The first type
4099 indexed into must be a pointer value, subsequent types can be arrays, vectors
4100 and structs. Note that subsequent types being indexed into can never be
4101 pointers, since that would require loading the pointer before continuing
4102 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4103
4104<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4105 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4106 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4107 vector, integers of any width are allowed, and they are not required to be
4108 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4110<p>For example, let's consider a C code fragment and how it gets compiled to
4111 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4112
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4113<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4114<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4115struct RT {
4116 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4117 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4118 char C;
4119};
4120struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4121 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4122 double Y;
4123 struct RT Z;
4124};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4125
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4126int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4127 return &amp;s[1].Z.B[5][13];
4128}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4129</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4130</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4131
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4132<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4133
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4134<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4135<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4136%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4137%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4138
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4139define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4140entry:
4141 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4142 ret i32* %reg
4143}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4144</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4145</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4146
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4147<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4148<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4150 }</tt>' type, a structure. The second index indexes into the third element
4151 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4152 i8 }</tt>' type, another structure. The third index indexes into the second
4153 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4154 array. The two dimensions of the array are subscripted into, yielding an
4155 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4156 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4158<p>Note that it is perfectly legal to index partially through a structure,
4159 returning a pointer to an inner element. Because of this, the LLVM code for
4160 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4161
4162<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4163 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4164 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4165 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4166 %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]4167 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4168 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4169 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4170 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4171</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4172
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4173<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4174 <tt>getelementptr</tt> is undefined if the base pointer is not an
4175 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4176 that would be formed by successive addition of the offsets implied by the
4177 indices to the base address with infinitely precise arithmetic are not an
4178 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4179 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4180 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4181
4182<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4183 the base address with silently-wrapping two's complement arithmetic, and
4184 the result value of the <tt>getelementptr</tt> may be outside the object
4185 pointed to by the base pointer. The result value may not necessarily be
4186 used to access memory though, even if it happens to point into allocated
4187 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4188 section for more information.</p>
4189
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4190<p>The getelementptr instruction is often confusing. For some more insight into
4191 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4192
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4193<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4194<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4195 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4196 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4197 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4198 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4199 <i>; yields i8*:eptr</i>
4200 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4201 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4202 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4203</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4204
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4205</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4206
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4207<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4208<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4209</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4211<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4213<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214 which all take a single operand and a type. They perform various bit
4215 conversions on the operand.</p>
4216
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4217</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4218
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4219<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4220<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4221 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4222</div>
4223<div class="doc_text">
4224
4225<h5>Syntax:</h5>
4226<pre>
4227 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4228</pre>
4229
4230<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4232 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4233
4234<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4236 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4237 size and type of the result, which must be
4238 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4239 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4240 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4241
4242<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4243<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4244 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4245 source size must be larger than the destination size, <tt>trunc</tt> cannot
4246 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4247
4248<h5>Example:</h5>
4249<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4250 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4251 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4252 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4253</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4255</div>
4256
4257<!-- _______________________________________________________________________ -->
4258<div class="doc_subsubsection">
4259 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4260</div>
4261<div class="doc_text">
4262
4263<h5>Syntax:</h5>
4264<pre>
4265 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4266</pre>
4267
4268<h5>Overview:</h5>
4269<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4271
4272
4273<h5>Arguments:</h5>
4274<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4275 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4276 also be of <a href="#t_integer">integer</a> type. The bit size of the
4277 <tt>value</tt> must be smaller than the bit size of the destination type,
4278 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4279
4280<h5>Semantics:</h5>
4281<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4283
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4284<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]4285
4286<h5>Example:</h5>
4287<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4288 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4289 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4290</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4292</div>
4293
4294<!-- _______________________________________________________________________ -->
4295<div class="doc_subsubsection">
4296 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4297</div>
4298<div class="doc_text">
4299
4300<h5>Syntax:</h5>
4301<pre>
4302 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4303</pre>
4304
4305<h5>Overview:</h5>
4306<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4307
4308<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4310 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4311 also be of <a href="#t_integer">integer</a> type. The bit size of the
4312 <tt>value</tt> must be smaller than the bit size of the destination type,
4313 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4314
4315<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4317 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4318 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4319
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4320<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]4321
4322<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4323<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4324 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4325 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4326</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4327
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4328</div>
4329
4330<!-- _______________________________________________________________________ -->
4331<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4332 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4333</div>
4334
4335<div class="doc_text">
4336
4337<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4338<pre>
4339 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4340</pre>
4341
4342<h5>Overview:</h5>
4343<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4344 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4345
4346<h5>Arguments:</h5>
4347<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4349 to cast it to. The size of <tt>value</tt> must be larger than the size of
4350 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4351 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4352
4353<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4354<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4355 <a href="#t_floating">floating point</a> type to a smaller
4356 <a href="#t_floating">floating point</a> type. If the value cannot fit
4357 within the destination type, <tt>ty2</tt>, then the results are
4358 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4359
4360<h5>Example:</h5>
4361<pre>
4362 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4363 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4364</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4365
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4366</div>
4367
4368<!-- _______________________________________________________________________ -->
4369<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4370 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4371</div>
4372<div class="doc_text">
4373
4374<h5>Syntax:</h5>
4375<pre>
4376 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4377</pre>
4378
4379<h5>Overview:</h5>
4380<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4381 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4382
4383<h5>Arguments:</h5>
4384<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4385 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4386 a <a href="#t_floating">floating point</a> type to cast it to. The source
4387 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4388
4389<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4390<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391 <a href="#t_floating">floating point</a> type to a larger
4392 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4393 used to make a <i>no-op cast</i> because it always changes bits. Use
4394 <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]4395
4396<h5>Example:</h5>
4397<pre>
4398 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4399 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4400</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4401
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4402</div>
4403
4404<!-- _______________________________________________________________________ -->
4405<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4406 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4407</div>
4408<div class="doc_text">
4409
4410<h5>Syntax:</h5>
4411<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4412 &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]4413</pre>
4414
4415<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4416<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4417 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4418
4419<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4420<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4421 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4422 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4423 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4424 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4425
4426<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4427<p>The '<tt>fptoui</tt>' instruction converts its
4428 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4429 towards zero) unsigned integer value. If the value cannot fit
4430 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4431
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4432<h5>Example:</h5>
4433<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4434 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4435 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4436 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4437</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4438
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4439</div>
4440
4441<!-- _______________________________________________________________________ -->
4442<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4443 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4444</div>
4445<div class="doc_text">
4446
4447<h5>Syntax:</h5>
4448<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4449 &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]4450</pre>
4451
4452<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4453<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454 <a href="#t_floating">floating point</a> <tt>value</tt> to
4455 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4456
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4457<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4458<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4459 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4460 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4461 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4462 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4463
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4464<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4465<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4466 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4467 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4468 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4469
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4470<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4471<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4472 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4473 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4474 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4475</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4476
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4477</div>
4478
4479<!-- _______________________________________________________________________ -->
4480<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4481 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4482</div>
4483<div class="doc_text">
4484
4485<h5>Syntax:</h5>
4486<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4487 &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]4488</pre>
4489
4490<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4491<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4492 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4493
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4494<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4495<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4496 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4497 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4498 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4499 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4500
4501<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4502<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503 integer quantity and converts it to the corresponding floating point
4504 value. If the value cannot fit in the floating point value, the results are
4505 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4506
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4507<h5>Example:</h5>
4508<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4509 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4510 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4511</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4512
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4513</div>
4514
4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4517 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4518</div>
4519<div class="doc_text">
4520
4521<h5>Syntax:</h5>
4522<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4523 &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]4524</pre>
4525
4526<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4527<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4528 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4529
4530<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4531<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4532 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4533 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4534 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4535 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4536
4537<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4539 quantity and converts it to the corresponding floating point value. If the
4540 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4541
4542<h5>Example:</h5>
4543<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4544 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4545 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4546</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4547
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4548</div>
4549
4550<!-- _______________________________________________________________________ -->
4551<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4552 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4553</div>
4554<div class="doc_text">
4555
4556<h5>Syntax:</h5>
4557<pre>
4558 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4559</pre>
4560
4561<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4562<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4563 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4564
4565<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4566<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4567 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4568 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4569
4570<h5>Semantics:</h5>
4571<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4572 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4573 truncating or zero extending that value to the size of the integer type. If
4574 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4575 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4576 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4577 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4578
4579<h5>Example:</h5>
4580<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4581 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4582 %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]4583</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4584
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4585</div>
4586
4587<!-- _______________________________________________________________________ -->
4588<div class="doc_subsubsection">
4589 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4590</div>
4591<div class="doc_text">
4592
4593<h5>Syntax:</h5>
4594<pre>
4595 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4596</pre>
4597
4598<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4599<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4600 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4601
4602<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4603<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4604 value to cast, and a type to cast it to, which must be a
4605 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4606
4607<h5>Semantics:</h5>
4608<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4609 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4610 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4611 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4612 than the size of a pointer then a zero extension is done. If they are the
4613 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4614
4615<h5>Example:</h5>
4616<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4617 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4618 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4619 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4620</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4621
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4622</div>
4623
4624<!-- _______________________________________________________________________ -->
4625<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4626 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4627</div>
4628<div class="doc_text">
4629
4630<h5>Syntax:</h5>
4631<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4632 &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]4633</pre>
4634
4635<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4636<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4638
4639<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4641 non-aggregate first class value, and a type to cast it to, which must also be
4642 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4643 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4644 identical. If the source type is a pointer, the destination type must also be
4645 a pointer. This instruction supports bitwise conversion of vectors to
4646 integers and to vectors of other types (as long as they have the same
4647 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4648
4649<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4650<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4652 this conversion. The conversion is done as if the <tt>value</tt> had been
4653 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4654 be converted to other pointer types with this instruction. To convert
4655 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4656 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4657
4658<h5>Example:</h5>
4659<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4660 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4661 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4662 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4663</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4664
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4665</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4666
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4667<!-- ======================================================================= -->
4668<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4670<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671
4672<p>The instructions in this category are the "miscellaneous" instructions, which
4673 defy better classification.</p>
4674
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4675</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4676
4677<!-- _______________________________________________________________________ -->
4678<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4679</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4680
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4681<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4682
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4683<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4684<pre>
4685 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4688<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4689<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4690 boolean values based on comparison of its two integer, integer vector, or
4691 pointer operands.</p>
4692
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4693<h5>Arguments:</h5>
4694<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4695 the condition code indicating the kind of comparison to perform. It is not a
4696 value, just a keyword. The possible condition code are:</p>
4697
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4698<ol>
4699 <li><tt>eq</tt>: equal</li>
4700 <li><tt>ne</tt>: not equal </li>
4701 <li><tt>ugt</tt>: unsigned greater than</li>
4702 <li><tt>uge</tt>: unsigned greater or equal</li>
4703 <li><tt>ult</tt>: unsigned less than</li>
4704 <li><tt>ule</tt>: unsigned less or equal</li>
4705 <li><tt>sgt</tt>: signed greater than</li>
4706 <li><tt>sge</tt>: signed greater or equal</li>
4707 <li><tt>slt</tt>: signed less than</li>
4708 <li><tt>sle</tt>: signed less or equal</li>
4709</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4711<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4712 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4713 typed. They must also be identical types.</p>
4714
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4715<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4717 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4718 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4719 result, as follows:</p>
4720
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4721<ol>
4722 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723 <tt>false</tt> otherwise. No sign interpretation is necessary or
4724 performed.</li>
4725
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4726 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>false</tt> otherwise. No sign interpretation is necessary or
4728 performed.</li>
4729
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4730 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4732
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4733 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4735 to <tt>op2</tt>.</li>
4736
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4737 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4738 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4739
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4740 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4742
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4743 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4745
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4746 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4747 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4748 to <tt>op2</tt>.</li>
4749
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4750 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4751 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4752
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4753 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4754 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4755</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4756
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4757<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758 values are compared as if they were integers.</p>
4759
4760<p>If the operands are integer vectors, then they are compared element by
4761 element. The result is an <tt>i1</tt> vector with the same number of elements
4762 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4763
4764<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4765<pre>
4766 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4767 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4768 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4769 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4770 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4771 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4772</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4773
4774<p>Note that the code generator does not yet support vector types with
4775 the <tt>icmp</tt> instruction.</p>
4776
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4777</div>
4778
4779<!-- _______________________________________________________________________ -->
4780<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4781</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4782
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4783<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4784
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4785<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786<pre>
4787 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4788</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4790<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4791<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4792 values based on comparison of its operands.</p>
4793
4794<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4795(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4796
4797<p>If the operands are floating point vectors, then the result type is a vector
4798 of boolean with the same number of elements as the operands being
4799 compared.</p>
4800
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4801<h5>Arguments:</h5>
4802<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4803 the condition code indicating the kind of comparison to perform. It is not a
4804 value, just a keyword. The possible condition code are:</p>
4805
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4806<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4807 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4808 <li><tt>oeq</tt>: ordered and equal</li>
4809 <li><tt>ogt</tt>: ordered and greater than </li>
4810 <li><tt>oge</tt>: ordered and greater than or equal</li>
4811 <li><tt>olt</tt>: ordered and less than </li>
4812 <li><tt>ole</tt>: ordered and less than or equal</li>
4813 <li><tt>one</tt>: ordered and not equal</li>
4814 <li><tt>ord</tt>: ordered (no nans)</li>
4815 <li><tt>ueq</tt>: unordered or equal</li>
4816 <li><tt>ugt</tt>: unordered or greater than </li>
4817 <li><tt>uge</tt>: unordered or greater than or equal</li>
4818 <li><tt>ult</tt>: unordered or less than </li>
4819 <li><tt>ule</tt>: unordered or less than or equal</li>
4820 <li><tt>une</tt>: unordered or not equal</li>
4821 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4822 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4823</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4824
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4825<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4826 <i>unordered</i> means that either operand may be a QNAN.</p>
4827
4828<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4829 a <a href="#t_floating">floating point</a> type or
4830 a <a href="#t_vector">vector</a> of floating point type. They must have
4831 identical types.</p>
4832
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4833<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4834<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4835 according to the condition code given as <tt>cond</tt>. If the operands are
4836 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4837 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4838 follows:</p>
4839
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4840<ol>
4841 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4843 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4844 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4845
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4846 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4847 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4848
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4849 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4850 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4851
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4852 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4854
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4855 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4856 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4857
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4858 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4859 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4860
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4861 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4863 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4864 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4865
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4866 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4867 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4868
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4869 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4870 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4871
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4872 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4873 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4874
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4875 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4876 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4877
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4878 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4879 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4880
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4881 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4882
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4883 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4884</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4885
4886<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887<pre>
4888 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4889 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4890 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4891 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4892</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4893
4894<p>Note that the code generator does not yet support vector types with
4895 the <tt>fcmp</tt> instruction.</p>
4896
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4897</div>
4898
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4899<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4900<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4901 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4902</div>
4903
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4904<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4905
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4906<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4907<pre>
4908 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4909</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4910
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4911<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4912<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4913 SSA graph representing the function.</p>
4914
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4915<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4916<p>The type of the incoming values is specified with the first type field. After
4917 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4918 one pair for each predecessor basic block of the current block. Only values
4919 of <a href="#t_firstclass">first class</a> type may be used as the value
4920 arguments to the PHI node. Only labels may be used as the label
4921 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4922
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4923<p>There must be no non-phi instructions between the start of a basic block and
4924 the PHI instructions: i.e. PHI instructions must be first in a basic
4925 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4926
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4927<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4928 occur on the edge from the corresponding predecessor block to the current
4929 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4930 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4931
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4932<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4933<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4934 specified by the pair corresponding to the predecessor basic block that
4935 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4936
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4937<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4938<pre>
4939Loop: ; Infinite loop that counts from 0 on up...
4940 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4941 %nextindvar = add i32 %indvar, 1
4942 br label %Loop
4943</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4944
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4945</div>
4946
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4947<!-- _______________________________________________________________________ -->
4948<div class="doc_subsubsection">
4949 <a name="i_select">'<tt>select</tt>' Instruction</a>
4950</div>
4951
4952<div class="doc_text">
4953
4954<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4955<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4956 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4957
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4958 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4959</pre>
4960
4961<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4962<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4963 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4964
4965
4966<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4967<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4968 values indicating the condition, and two values of the
4969 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4970 vectors and the condition is a scalar, then entire vectors are selected, not
4971 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4972
4973<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4975 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4976
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4977<p>If the condition is a vector of i1, then the value arguments must be vectors
4978 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4979
4980<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4981<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4982 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4983</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4984
4985<p>Note that the code generator does not yet support conditions
4986 with vector type.</p>
4987
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4988</div>
4989
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4990<!-- _______________________________________________________________________ -->
4991<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4992 <a name="i_call">'<tt>call</tt>' Instruction</a>
4993</div>
4994
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4995<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4996
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4997<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4998<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4999 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5000</pre>
5001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5002<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5003<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5004
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5005<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5006<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5007
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5008<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5009 <li>The optional "tail" marker indicates whether the callee function accesses
5010 any allocas or varargs in the caller. If the "tail" marker is present,
5011 the function call is eligible for tail call optimization. Note that calls
5012 may be marked "tail" even if they do not occur before
5013 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5014
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5015 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5016 convention</a> the call should use. If none is specified, the call
5017 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5020 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5021 '<tt>inreg</tt>' attributes are valid here.</li>
5022
5023 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5024 type of the return value. Functions that return no value are marked
5025 <tt><a href="#t_void">void</a></tt>.</li>
5026
5027 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5028 being invoked. The argument types must match the types implied by this
5029 signature. This type can be omitted if the function is not varargs and if
5030 the function type does not return a pointer to a function.</li>
5031
5032 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5033 be invoked. In most cases, this is a direct function invocation, but
5034 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5035 to function value.</li>
5036
5037 <li>'<tt>function args</tt>': argument list whose types match the function
5038 signature argument types. All arguments must be of
5039 <a href="#t_firstclass">first class</a> type. If the function signature
5040 indicates the function accepts a variable number of arguments, the extra
5041 arguments can be specified.</li>
5042
5043 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5044 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5045 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5046</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5047
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5048<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5049<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5050 a specified function, with its incoming arguments bound to the specified
5051 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5052 function, control flow continues with the instruction after the function
5053 call, and the return value of the function is bound to the result
5054 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5055
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5056<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5057<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5058 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5059 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5060 %X = tail call i32 @foo() <i>; yields i32</i>
5061 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5062 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5063
5064 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5065 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5066 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5067 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5068 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5069 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5070</pre>
5071
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5072<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5073standard C99 library as being the C99 library functions, and may perform
5074optimizations or generate code for them under that assumption. This is
5075something we'd like to change in the future to provide better support for
5076freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5077
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5078</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5079
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5080<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5081<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5082 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5083</div>
5084
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5085<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5086
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5087<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5088<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5089 &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]5090</pre>
5091
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5092<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5093<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5094 the "variable argument" area of a function call. It is used to implement the
5095 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5096
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5097<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5098<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5099 argument. It returns a value of the specified argument type and increments
5100 the <tt>va_list</tt> to point to the next argument. The actual type
5101 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5102
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5103<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5104<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5105 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5106 to the next argument. For more information, see the variable argument
5107 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5108
5109<p>It is legal for this instruction to be called in a function which does not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5111 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5113<p><tt>va_arg</tt> is an LLVM instruction instead of
5114 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5115 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5116
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5117<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5118<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5119
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5120<p>Note that the code generator does not yet fully support va_arg on many
5121 targets. Also, it does not currently support va_arg with aggregate types on
5122 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5123
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5124</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5125
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5126<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5127<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5128<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5129
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5130<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5131
5132<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5133 well known names and semantics and are required to follow certain
5134 restrictions. Overall, these intrinsics represent an extension mechanism for
5135 the LLVM language that does not require changing all of the transformations
5136 in LLVM when adding to the language (or the bitcode reader/writer, the
5137 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5138
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5139<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5140 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5141 begin with this prefix. Intrinsic functions must always be external
5142 functions: you cannot define the body of intrinsic functions. Intrinsic
5143 functions may only be used in call or invoke instructions: it is illegal to
5144 take the address of an intrinsic function. Additionally, because intrinsic
5145 functions are part of the LLVM language, it is required if any are added that
5146 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5148<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5149 family of functions that perform the same operation but on different data
5150 types. Because LLVM can represent over 8 million different integer types,
5151 overloading is used commonly to allow an intrinsic function to operate on any
5152 integer type. One or more of the argument types or the result type can be
5153 overloaded to accept any integer type. Argument types may also be defined as
5154 exactly matching a previous argument's type or the result type. This allows
5155 an intrinsic function which accepts multiple arguments, but needs all of them
5156 to be of the same type, to only be overloaded with respect to a single
5157 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5158
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5159<p>Overloaded intrinsics will have the names of its overloaded argument types
5160 encoded into its function name, each preceded by a period. Only those types
5161 which are overloaded result in a name suffix. Arguments whose type is matched
5162 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5163 can take an integer of any width and returns an integer of exactly the same
5164 integer width. This leads to a family of functions such as
5165 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5166 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5167 suffix is required. Because the argument's type is matched against the return
5168 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5169
5170<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5171 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5172
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5173</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5174
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5175<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5176<div class="doc_subsection">
5177 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5178</div>
5179
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5180<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5181
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5182<p>Variable argument support is defined in LLVM with
5183 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5184 intrinsic functions. These functions are related to the similarly named
5185 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5186
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5187<p>All of these functions operate on arguments that use a target-specific value
5188 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5189 not define what this type is, so all transformations should be prepared to
5190 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5191
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5192<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5193 instruction and the variable argument handling intrinsic functions are
5194 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5195
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5196<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5197<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5198define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5199 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5200 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5201 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5202 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5203
5204 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5205 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5206
5207 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5208 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5209 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5210 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5211 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5212
5213 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5214 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5215 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5216}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5217
5218declare void @llvm.va_start(i8*)
5219declare void @llvm.va_copy(i8*, i8*)
5220declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5221</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5222</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5223
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5224</div>
5225
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5226<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5227<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5228 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5229</div>
5230
5231
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5232<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5233
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5234<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5235<pre>
5236 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5237</pre>
5238
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5239<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5241 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5242
5243<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5244<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5245
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5246<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5247<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5248 macro available in C. In a target-dependent way, it initializes
5249 the <tt>va_list</tt> element to which the argument points, so that the next
5250 call to <tt>va_arg</tt> will produce the first variable argument passed to
5251 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5252 need to know the last argument of the function as the compiler can figure
5253 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5255</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5256
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5257<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5258<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5259 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5260</div>
5261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5262<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5263
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5264<h5>Syntax:</h5>
5265<pre>
5266 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5267</pre>
5268
5269<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5270<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5271 which has been initialized previously
5272 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5273 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5274
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5275<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5276<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]5277
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5278<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5279<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5280 macro available in C. In a target-dependent way, it destroys
5281 the <tt>va_list</tt> element to which the argument points. Calls
5282 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5283 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5284 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5286</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5287
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5288<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5289<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5290 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5291</div>
5292
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5293<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5294
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5295<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5296<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5297 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5298</pre>
5299
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5300<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5301<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5302 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5303
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5304<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5305<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5306 The second argument is a pointer to a <tt>va_list</tt> element to copy
5307 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5308
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5309<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5310<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5311 macro available in C. In a target-dependent way, it copies the
5312 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5313 element. This intrinsic is necessary because
5314 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5315 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5317</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5318
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5319<!-- ======================================================================= -->
5320<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5321 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5322</div>
5323
5324<div class="doc_text">
5325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5326<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5327Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5328intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5329roots on the stack</a>, as well as garbage collector implementations that
5330require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5331barriers. Front-ends for type-safe garbage collected languages should generate
5332these intrinsics to make use of the LLVM garbage collectors. For more details,
5333see <a href="GarbageCollection.html">Accurate Garbage Collection with
5334LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5335
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5336<p>The garbage collection intrinsics only operate on objects in the generic
5337 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5338
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5339</div>
5340
5341<!-- _______________________________________________________________________ -->
5342<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5343 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5344</div>
5345
5346<div class="doc_text">
5347
5348<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5349<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5350 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5351</pre>
5352
5353<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5354<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5355 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5356
5357<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5358<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5359 root pointer. The second pointer (which must be either a constant or a
5360 global value address) contains the meta-data to be associated with the
5361 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5362
5363<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5364<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5365 location. At compile-time, the code generator generates information to allow
5366 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5367 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5368 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5369
5370</div>
5371
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5372<!-- _______________________________________________________________________ -->
5373<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5374 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5375</div>
5376
5377<div class="doc_text">
5378
5379<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5380<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5381 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5382</pre>
5383
5384<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5385<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5386 locations, allowing garbage collector implementations that require read
5387 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5388
5389<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5390<p>The second argument is the address to read from, which should be an address
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5391 allocated from the garbage collector. The first object is a pointer to the
5392 start of the referenced object, if needed by the language runtime (otherwise
5393 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5394
5395<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5396<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5397 instruction, but may be replaced with substantially more complex code by the
5398 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5399 may only be used in a function which <a href="#gc">specifies a GC
5400 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5401
5402</div>
5403
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5404<!-- _______________________________________________________________________ -->
5405<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5406 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5407</div>
5408
5409<div class="doc_text">
5410
5411<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5412<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5413 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5414</pre>
5415
5416<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5417<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5418 locations, allowing garbage collector implementations that require write
5419 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5420
5421<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5422<p>The first argument is the reference to store, the second is the start of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5423 object to store it to, and the third is the address of the field of Obj to
5424 store to. If the runtime does not require a pointer to the object, Obj may
5425 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5426
5427<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5428<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5429 instruction, but may be replaced with substantially more complex code by the
5430 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5431 may only be used in a function which <a href="#gc">specifies a GC
5432 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5433
5434</div>
5435
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5436<!-- ======================================================================= -->
5437<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5438 <a name="int_codegen">Code Generator Intrinsics</a>
5439</div>
5440
5441<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442
5443<p>These intrinsics are provided by LLVM to expose special features that may
5444 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5445
5446</div>
5447
5448<!-- _______________________________________________________________________ -->
5449<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5450 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5451</div>
5452
5453<div class="doc_text">
5454
5455<h5>Syntax:</h5>
5456<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5457 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5458</pre>
5459
5460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5461<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5462 target-specific value indicating the return address of the current function
5463 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5464
5465<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5466<p>The argument to this intrinsic indicates which function to return the address
5467 for. Zero indicates the calling function, one indicates its caller, etc.
5468 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5469
5470<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5471<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5472 indicating the return address of the specified call frame, or zero if it
5473 cannot be identified. The value returned by this intrinsic is likely to be
5474 incorrect or 0 for arguments other than zero, so it should only be used for
5475 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5477<p>Note that calling this intrinsic does not prevent function inlining or other
5478 aggressive transformations, so the value returned may not be that of the
5479 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5480
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5481</div>
5482
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5483<!-- _______________________________________________________________________ -->
5484<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5485 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5486</div>
5487
5488<div class="doc_text">
5489
5490<h5>Syntax:</h5>
5491<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5492 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5493</pre>
5494
5495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5496<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5497 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5498
5499<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The argument to this intrinsic indicates which function to return the frame
5501 pointer for. Zero indicates the calling function, one indicates its caller,
5502 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5503
5504<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5505<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5506 indicating the frame address of the specified call frame, or zero if it
5507 cannot be identified. The value returned by this intrinsic is likely to be
5508 incorrect or 0 for arguments other than zero, so it should only be used for
5509 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5511<p>Note that calling this intrinsic does not prevent function inlining or other
5512 aggressive transformations, so the value returned may not be that of the
5513 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5514
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5515</div>
5516
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5517<!-- _______________________________________________________________________ -->
5518<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5519 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5520</div>
5521
5522<div class="doc_text">
5523
5524<h5>Syntax:</h5>
5525<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5526 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5527</pre>
5528
5529<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5530<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5531 of the function stack, for use
5532 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5533 useful for implementing language features like scoped automatic variable
5534 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5535
5536<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5537<p>This intrinsic returns a opaque pointer value that can be passed
5538 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5539 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5540 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5541 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5542 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5543 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5544
5545</div>
5546
5547<!-- _______________________________________________________________________ -->
5548<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5549 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5550</div>
5551
5552<div class="doc_text">
5553
5554<h5>Syntax:</h5>
5555<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5556 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5557</pre>
5558
5559<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5560<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5561 the function stack to the state it was in when the
5562 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5563 executed. This is useful for implementing language features like scoped
5564 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5565
5566<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<p>See the description
5568 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5569
5570</div>
5571
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5572<!-- _______________________________________________________________________ -->
5573<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5574 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5575</div>
5576
5577<div class="doc_text">
5578
5579<h5>Syntax:</h5>
5580<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5581 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]5582</pre>
5583
5584<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5585<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5586 insert a prefetch instruction if supported; otherwise, it is a noop.
5587 Prefetches have no effect on the behavior of the program but can change its
5588 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5589
5590<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5592 specifier determining if the fetch should be for a read (0) or write (1),
5593 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5594 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5595 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5596
5597<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5598<p>This intrinsic does not modify the behavior of the program. In particular,
5599 prefetches cannot trap and do not produce a value. On targets that support
5600 this intrinsic, the prefetch can provide hints to the processor cache for
5601 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5602
5603</div>
5604
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5605<!-- _______________________________________________________________________ -->
5606<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5607 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5608</div>
5609
5610<div class="doc_text">
5611
5612<h5>Syntax:</h5>
5613<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5614 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5615</pre>
5616
5617<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5618<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5619 Counter (PC) in a region of code to simulators and other tools. The method
5620 is target specific, but it is expected that the marker will use exported
5621 symbols to transmit the PC of the marker. The marker makes no guarantees
5622 that it will remain with any specific instruction after optimizations. It is
5623 possible that the presence of a marker will inhibit optimizations. The
5624 intended use is to be inserted after optimizations to allow correlations of
5625 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5626
5627<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5629
5630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631<p>This intrinsic does not modify the behavior of the program. Backends that do
5632 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5633
5634</div>
5635
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5636<!-- _______________________________________________________________________ -->
5637<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5638 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5639</div>
5640
5641<div class="doc_text">
5642
5643<h5>Syntax:</h5>
5644<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5645 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5646</pre>
5647
5648<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5649<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5650 counter register (or similar low latency, high accuracy clocks) on those
5651 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5652 should map to RPCC. As the backing counters overflow quickly (on the order
5653 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5654
5655<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5656<p>When directly supported, reading the cycle counter should not modify any
5657 memory. Implementations are allowed to either return a application specific
5658 value or a system wide value. On backends without support, this is lowered
5659 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5660
5661</div>
5662
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5663<!-- ======================================================================= -->
5664<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5665 <a name="int_libc">Standard C Library Intrinsics</a>
5666</div>
5667
5668<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5669
5670<p>LLVM provides intrinsics for a few important standard C library functions.
5671 These intrinsics allow source-language front-ends to pass information about
5672 the alignment of the pointer arguments to the code generator, providing
5673 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5674
5675</div>
5676
5677<!-- _______________________________________________________________________ -->
5678<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5679 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5680</div>
5681
5682<div class="doc_text">
5683
5684<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5685<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5686 integer bit width. Not all targets support all bit widths however.</p>
5687
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5688<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5689 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5690 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5691 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5692 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5693 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5694 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5695 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5696 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5697</pre>
5698
5699<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5700<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5701 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5702
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5703<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5704 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5705
5706<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5707<p>The first argument is a pointer to the destination, the second is a pointer
5708 to the source. The third argument is an integer argument specifying the
5709 number of bytes to copy, and the fourth argument is the alignment of the
5710 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5711
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5712<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5713 then the caller guarantees that both the source and destination pointers are
5714 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5715
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5716<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5717<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5718 source location to the destination location, which are not allowed to
5719 overlap. It copies "len" bytes of memory over. If the argument is known to
5720 be aligned to some boundary, this can be specified as the fourth argument,
5721 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5722
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5723</div>
5724
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5725<!-- _______________________________________________________________________ -->
5726<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5727 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5728</div>
5729
5730<div class="doc_text">
5731
5732<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5733<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5734 width. Not all targets support all bit widths however.</p>
5735
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5736<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5737 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5738 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5739 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5740 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5741 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5742 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5743 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5744 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5745</pre>
5746
5747<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5748<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5749 source location to the destination location. It is similar to the
5750 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5751 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5753<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5754 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5755
5756<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5757<p>The first argument is a pointer to the destination, the second is a pointer
5758 to the source. The third argument is an integer argument specifying the
5759 number of bytes to copy, and the fourth argument is the alignment of the
5760 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5761
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5762<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5763 then the caller guarantees that the source and destination pointers are
5764 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5765
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5766<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5768 source location to the destination location, which may overlap. It copies
5769 "len" bytes of memory over. If the argument is known to be aligned to some
5770 boundary, this can be specified as the fourth argument, otherwise it should
5771 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5772
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5773</div>
5774
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5775<!-- _______________________________________________________________________ -->
5776<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5777 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5778</div>
5779
5780<div class="doc_text">
5781
5782<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5783<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5784 width. Not all targets support all bit widths however.</p>
5785
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5786<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5787 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5788 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5789 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5790 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5791 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5792 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5793 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5794 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5795</pre>
5796
5797<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5799 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5801<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5802 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5803
5804<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5805<p>The first argument is a pointer to the destination to fill, the second is the
5806 byte value to fill it with, the third argument is an integer argument
5807 specifying the number of bytes to fill, and the fourth argument is the known
5808 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5809
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5810<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5811 then the caller guarantees that the destination pointer is aligned to that
5812 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813
5814<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5815<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5816 at the destination location. If the argument is known to be aligned to some
5817 boundary, this can be specified as the fourth argument, otherwise it should
5818 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5819
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5820</div>
5821
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5822<!-- _______________________________________________________________________ -->
5823<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5824 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5825</div>
5826
5827<div class="doc_text">
5828
5829<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5830<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5831 floating point or vector of floating point type. Not all targets support all
5832 types however.</p>
5833
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5834<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5835 declare float @llvm.sqrt.f32(float %Val)
5836 declare double @llvm.sqrt.f64(double %Val)
5837 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5838 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5839 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5840</pre>
5841
5842<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5843<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5844 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5845 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5846 behavior for negative numbers other than -0.0 (which allows for better
5847 optimization, because there is no need to worry about errno being
5848 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5849
5850<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5851<p>The argument and return value are floating point numbers of the same
5852 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5853
5854<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855<p>This function returns the sqrt of the specified operand if it is a
5856 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5857
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5858</div>
5859
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5860<!-- _______________________________________________________________________ -->
5861<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5862 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5863</div>
5864
5865<div class="doc_text">
5866
5867<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5868<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5869 floating point or vector of floating point type. Not all targets support all
5870 types however.</p>
5871
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5872<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5873 declare float @llvm.powi.f32(float %Val, i32 %power)
5874 declare double @llvm.powi.f64(double %Val, i32 %power)
5875 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5876 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5877 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5878</pre>
5879
5880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5882 specified (positive or negative) power. The order of evaluation of
5883 multiplications is not defined. When a vector of floating point type is
5884 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5885
5886<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5887<p>The second argument is an integer power, and the first is a value to raise to
5888 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5889
5890<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5891<p>This function returns the first value raised to the second power with an
5892 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5893
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5894</div>
5895
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5896<!-- _______________________________________________________________________ -->
5897<div class="doc_subsubsection">
5898 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5899</div>
5900
5901<div class="doc_text">
5902
5903<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5904<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5905 floating point or vector of floating point type. Not all targets support all
5906 types however.</p>
5907
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5908<pre>
5909 declare float @llvm.sin.f32(float %Val)
5910 declare double @llvm.sin.f64(double %Val)
5911 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5912 declare fp128 @llvm.sin.f128(fp128 %Val)
5913 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5914</pre>
5915
5916<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5918
5919<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5920<p>The argument and return value are floating point numbers of the same
5921 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5922
5923<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5924<p>This function returns the sine of the specified operand, returning the same
5925 values as the libm <tt>sin</tt> functions would, and handles error conditions
5926 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5927
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5928</div>
5929
5930<!-- _______________________________________________________________________ -->
5931<div class="doc_subsubsection">
5932 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5933</div>
5934
5935<div class="doc_text">
5936
5937<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5938<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5939 floating point or vector of floating point type. Not all targets support all
5940 types however.</p>
5941
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5942<pre>
5943 declare float @llvm.cos.f32(float %Val)
5944 declare double @llvm.cos.f64(double %Val)
5945 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5946 declare fp128 @llvm.cos.f128(fp128 %Val)
5947 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5948</pre>
5949
5950<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5951<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5952
5953<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954<p>The argument and return value are floating point numbers of the same
5955 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5956
5957<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5958<p>This function returns the cosine of the specified operand, returning the same
5959 values as the libm <tt>cos</tt> functions would, and handles error conditions
5960 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5961
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5962</div>
5963
5964<!-- _______________________________________________________________________ -->
5965<div class="doc_subsubsection">
5966 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5967</div>
5968
5969<div class="doc_text">
5970
5971<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5972<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5973 floating point or vector of floating point type. Not all targets support all
5974 types however.</p>
5975
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5976<pre>
5977 declare float @llvm.pow.f32(float %Val, float %Power)
5978 declare double @llvm.pow.f64(double %Val, double %Power)
5979 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5980 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5981 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5982</pre>
5983
5984<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5985<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5986 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5987
5988<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5989<p>The second argument is a floating point power, and the first is a value to
5990 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5991
5992<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5993<p>This function returns the first value raised to the second power, returning
5994 the same values as the libm <tt>pow</tt> functions would, and handles error
5995 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5996
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5997</div>
5998
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5999<!-- ======================================================================= -->
6000<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6001 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6002</div>
6003
6004<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6005
6006<p>LLVM provides intrinsics for a few important bit manipulation operations.
6007 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6008
6009</div>
6010
6011<!-- _______________________________________________________________________ -->
6012<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6013 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6014</div>
6015
6016<div class="doc_text">
6017
6018<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6019<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6020 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6021
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6022<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6023 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6024 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6025 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6026</pre>
6027
6028<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6029<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6030 values with an even number of bytes (positive multiple of 16 bits). These
6031 are useful for performing operations on data that is not in the target's
6032 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6033
6034<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6035<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6036 and low byte of the input i16 swapped. Similarly,
6037 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6038 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6039 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6040 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6041 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6042 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6043
6044</div>
6045
6046<!-- _______________________________________________________________________ -->
6047<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6048 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6049</div>
6050
6051<div class="doc_text">
6052
6053<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6054<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6055 width. Not all targets support all bit widths however.</p>
6056
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6057<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6058 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6059 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6060 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6061 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6062 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6063</pre>
6064
6065<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6067 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6068
6069<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6070<p>The only argument is the value to be counted. The argument may be of any
6071 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6072
6073<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6075
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6076</div>
6077
6078<!-- _______________________________________________________________________ -->
6079<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6080 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6081</div>
6082
6083<div class="doc_text">
6084
6085<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6086<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6087 integer bit width. Not all targets support all bit widths however.</p>
6088
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6089<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6090 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6091 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6092 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6093 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6094 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6095</pre>
6096
6097<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6098<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6099 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6100
6101<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The only argument is the value to be counted. The argument may be of any
6103 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6104
6105<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6106<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6107 zeros in a variable. If the src == 0 then the result is the size in bits of
6108 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6109
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6110</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6111
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6112<!-- _______________________________________________________________________ -->
6113<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6114 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6115</div>
6116
6117<div class="doc_text">
6118
6119<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6120<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6121 integer bit width. Not all targets support all bit widths however.</p>
6122
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6123<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6124 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6125 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6126 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6127 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6128 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6129</pre>
6130
6131<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6132<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6133 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6134
6135<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136<p>The only argument is the value to be counted. The argument may be of any
6137 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6138
6139<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6140<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6141 zeros in a variable. If the src == 0 then the result is the size in bits of
6142 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6143
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6144</div>
6145
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6146<!-- ======================================================================= -->
6147<div class="doc_subsection">
6148 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6149</div>
6150
6151<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6152
6153<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6154
6155</div>
6156
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6157<!-- _______________________________________________________________________ -->
6158<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6159 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6160</div>
6161
6162<div class="doc_text">
6163
6164<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6165<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6166 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6167
6168<pre>
6169 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6170 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6171 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6172</pre>
6173
6174<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6175<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6176 a signed addition of the two arguments, and indicate whether an overflow
6177 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6178
6179<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6180<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6181 be of integer types of any bit width, but they must have the same bit
6182 width. The second element of the result structure must be of
6183 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6184 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6185
6186<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6187<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6188 a signed addition of the two variables. They return a structure &mdash; the
6189 first element of which is the signed summation, and the second element of
6190 which is a bit specifying if the signed summation resulted in an
6191 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6192
6193<h5>Examples:</h5>
6194<pre>
6195 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6196 %sum = extractvalue {i32, i1} %res, 0
6197 %obit = extractvalue {i32, i1} %res, 1
6198 br i1 %obit, label %overflow, label %normal
6199</pre>
6200
6201</div>
6202
6203<!-- _______________________________________________________________________ -->
6204<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6205 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6206</div>
6207
6208<div class="doc_text">
6209
6210<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6211<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6212 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6213
6214<pre>
6215 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6216 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6217 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6218</pre>
6219
6220<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6221<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6222 an unsigned addition of the two arguments, and indicate whether a carry
6223 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6224
6225<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6226<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6227 be of integer types of any bit width, but they must have the same bit
6228 width. The second element of the result structure must be of
6229 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6230 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6231
6232<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6233<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6234 an unsigned addition of the two arguments. They return a structure &mdash;
6235 the first element of which is the sum, and the second element of which is a
6236 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6237
6238<h5>Examples:</h5>
6239<pre>
6240 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6241 %sum = extractvalue {i32, i1} %res, 0
6242 %obit = extractvalue {i32, i1} %res, 1
6243 br i1 %obit, label %carry, label %normal
6244</pre>
6245
6246</div>
6247
6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6250 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6251</div>
6252
6253<div class="doc_text">
6254
6255<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6256<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6258
6259<pre>
6260 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6261 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6262 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6263</pre>
6264
6265<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6266<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6267 a signed subtraction of the two arguments, and indicate whether an overflow
6268 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6269
6270<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6271<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272 be of integer types of any bit width, but they must have the same bit
6273 width. The second element of the result structure must be of
6274 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6275 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6276
6277<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6278<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6279 a signed subtraction of the two arguments. They return a structure &mdash;
6280 the first element of which is the subtraction, and the second element of
6281 which is a bit specifying if the signed subtraction resulted in an
6282 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6283
6284<h5>Examples:</h5>
6285<pre>
6286 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6287 %sum = extractvalue {i32, i1} %res, 0
6288 %obit = extractvalue {i32, i1} %res, 1
6289 br i1 %obit, label %overflow, label %normal
6290</pre>
6291
6292</div>
6293
6294<!-- _______________________________________________________________________ -->
6295<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6296 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6297</div>
6298
6299<div class="doc_text">
6300
6301<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6302<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6303 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6304
6305<pre>
6306 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6307 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6308 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6309</pre>
6310
6311<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6312<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6313 an unsigned subtraction of the two arguments, and indicate whether an
6314 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6315
6316<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6317<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6318 be of integer types of any bit width, but they must have the same bit
6319 width. The second element of the result structure must be of
6320 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6321 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6322
6323<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6324<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6325 an unsigned subtraction of the two arguments. They return a structure &mdash;
6326 the first element of which is the subtraction, and the second element of
6327 which is a bit specifying if the unsigned subtraction resulted in an
6328 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6329
6330<h5>Examples:</h5>
6331<pre>
6332 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6333 %sum = extractvalue {i32, i1} %res, 0
6334 %obit = extractvalue {i32, i1} %res, 1
6335 br i1 %obit, label %overflow, label %normal
6336</pre>
6337
6338</div>
6339
6340<!-- _______________________________________________________________________ -->
6341<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6342 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6343</div>
6344
6345<div class="doc_text">
6346
6347<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6348<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6349 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6350
6351<pre>
6352 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6353 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6354 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6355</pre>
6356
6357<h5>Overview:</h5>
6358
6359<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6360 a signed multiplication of the two arguments, and indicate whether an
6361 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6362
6363<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6364<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6365 be of integer types of any bit width, but they must have the same bit
6366 width. The second element of the result structure must be of
6367 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6368 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6369
6370<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6371<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6372 a signed multiplication of the two arguments. They return a structure &mdash;
6373 the first element of which is the multiplication, and the second element of
6374 which is a bit specifying if the signed multiplication resulted in an
6375 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6376
6377<h5>Examples:</h5>
6378<pre>
6379 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6380 %sum = extractvalue {i32, i1} %res, 0
6381 %obit = extractvalue {i32, i1} %res, 1
6382 br i1 %obit, label %overflow, label %normal
6383</pre>
6384
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6385</div>
6386
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6387<!-- _______________________________________________________________________ -->
6388<div class="doc_subsubsection">
6389 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6390</div>
6391
6392<div class="doc_text">
6393
6394<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6395<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6396 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6397
6398<pre>
6399 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6400 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6401 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6402</pre>
6403
6404<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6405<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6406 a unsigned multiplication of the two arguments, and indicate whether an
6407 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6408
6409<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6410<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6411 be of integer types of any bit width, but they must have the same bit
6412 width. The second element of the result structure must be of
6413 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6414 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6415
6416<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6417<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6418 an unsigned multiplication of the two arguments. They return a structure
6419 &mdash; the first element of which is the multiplication, and the second
6420 element of which is a bit specifying if the unsigned multiplication resulted
6421 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6422
6423<h5>Examples:</h5>
6424<pre>
6425 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6426 %sum = extractvalue {i32, i1} %res, 0
6427 %obit = extractvalue {i32, i1} %res, 1
6428 br i1 %obit, label %overflow, label %normal
6429</pre>
6430
6431</div>
6432
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6433<!-- ======================================================================= -->
6434<div class="doc_subsection">
6435 <a name="int_debugger">Debugger Intrinsics</a>
6436</div>
6437
6438<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6439
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6440<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6441 prefix), are described in
6442 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6443 Level Debugging</a> document.</p>
6444
6445</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6446
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6447<!-- ======================================================================= -->
6448<div class="doc_subsection">
6449 <a name="int_eh">Exception Handling Intrinsics</a>
6450</div>
6451
6452<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6453
6454<p>The LLVM exception handling intrinsics (which all start with
6455 <tt>llvm.eh.</tt> prefix), are described in
6456 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6457 Handling</a> document.</p>
6458
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6459</div>
6460
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6461<!-- ======================================================================= -->
6462<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6463 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6464</div>
6465
6466<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6467
6468<p>This intrinsic makes it possible to excise one parameter, marked with
6469 the <tt>nest</tt> attribute, from a function. The result is a callable
6470 function pointer lacking the nest parameter - the caller does not need to
6471 provide a value for it. Instead, the value to use is stored in advance in a
6472 "trampoline", a block of memory usually allocated on the stack, which also
6473 contains code to splice the nest value into the argument list. This is used
6474 to implement the GCC nested function address extension.</p>
6475
6476<p>For example, if the function is
6477 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6478 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6479 follows:</p>
6480
6481<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6482<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6483 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6484 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6485 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6486 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6487</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6488</div>
6489
6490<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6491 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6492
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6493</div>
6494
6495<!-- _______________________________________________________________________ -->
6496<div class="doc_subsubsection">
6497 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6498</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6499
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6500<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6501
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6502<h5>Syntax:</h5>
6503<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6504 declare 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]6505</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6506
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6507<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6508<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6509 function pointer suitable for executing it.</p>
6510
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6511<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6512<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6513 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6514 sufficiently aligned block of memory; this memory is written to by the
6515 intrinsic. Note that the size and the alignment are target-specific - LLVM
6516 currently provides no portable way of determining them, so a front-end that
6517 generates this intrinsic needs to have some target-specific knowledge.
6518 The <tt>func</tt> argument must hold a function bitcast to
6519 an <tt>i8*</tt>.</p>
6520
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6521<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6522<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6523 dependent code, turning it into a function. A pointer to this function is
6524 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6525 function pointer type</a> before being called. The new function's signature
6526 is the same as that of <tt>func</tt> with any arguments marked with
6527 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6528 is allowed, and it must be of pointer type. Calling the new function is
6529 equivalent to calling <tt>func</tt> with the same argument list, but
6530 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6531 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6532 by <tt>tramp</tt> is modified, then the effect of any later call to the
6533 returned function pointer is undefined.</p>
6534
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6535</div>
6536
6537<!-- ======================================================================= -->
6538<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6539 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6540</div>
6541
6542<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6545 hardware constructs for atomic operations and memory synchronization. This
6546 provides an interface to the hardware, not an interface to the programmer. It
6547 is aimed at a low enough level to allow any programming models or APIs
6548 (Application Programming Interfaces) which need atomic behaviors to map
6549 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6550 hardware provides a "universal IR" for source languages, it also provides a
6551 starting point for developing a "universal" atomic operation and
6552 synchronization IR.</p>
6553
6554<p>These do <em>not</em> form an API such as high-level threading libraries,
6555 software transaction memory systems, atomic primitives, and intrinsic
6556 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6557 application libraries. The hardware interface provided by LLVM should allow
6558 a clean implementation of all of these APIs and parallel programming models.
6559 No one model or paradigm should be selected above others unless the hardware
6560 itself ubiquitously does so.</p>
6561
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6562</div>
6563
6564<!-- _______________________________________________________________________ -->
6565<div class="doc_subsubsection">
6566 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6567</div>
6568<div class="doc_text">
6569<h5>Syntax:</h5>
6570<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6571 declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt; )
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6572</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6573
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6574<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6575<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6576 specific pairs of memory access types.</p>
6577
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6578<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6579<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6580 The first four arguments enables a specific barrier as listed below. The
6581 fith argument specifies that the barrier applies to io or device or uncached
6582 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6583
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6584<ul>
6585 <li><tt>ll</tt>: load-load barrier</li>
6586 <li><tt>ls</tt>: load-store barrier</li>
6587 <li><tt>sl</tt>: store-load barrier</li>
6588 <li><tt>ss</tt>: store-store barrier</li>
6589 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6590</ul>
6591
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6592<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6593<p>This intrinsic causes the system to enforce some ordering constraints upon
6594 the loads and stores of the program. This barrier does not
6595 indicate <em>when</em> any events will occur, it only enforces
6596 an <em>order</em> in which they occur. For any of the specified pairs of load
6597 and store operations (f.ex. load-load, or store-load), all of the first
6598 operations preceding the barrier will complete before any of the second
6599 operations succeeding the barrier begin. Specifically the semantics for each
6600 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6601
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6602<ul>
6603 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6604 after the barrier begins.</li>
6605 <li><tt>ls</tt>: All loads before the barrier must complete before any
6606 store after the barrier begins.</li>
6607 <li><tt>ss</tt>: All stores before the barrier must complete before any
6608 store after the barrier begins.</li>
6609 <li><tt>sl</tt>: All stores before the barrier must complete before any
6610 load after the barrier begins.</li>
6611</ul>
6612
6613<p>These semantics are applied with a logical "and" behavior when more than one
6614 is enabled in a single memory barrier intrinsic.</p>
6615
6616<p>Backends may implement stronger barriers than those requested when they do
6617 not support as fine grained a barrier as requested. Some architectures do
6618 not need all types of barriers and on such architectures, these become
6619 noops.</p>
6620
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6621<h5>Example:</h5>
6622<pre>
6623%ptr = malloc i32
6624 store i32 4, %ptr
6625
6626%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6627 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6628 <i>; guarantee the above finishes</i>
6629 store i32 8, %ptr <i>; before this begins</i>
6630</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6631
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6632</div>
6633
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6634<!-- _______________________________________________________________________ -->
6635<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6636 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6637</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6638
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6639<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6640
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6641<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6642<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6643 any integer bit width and for different address spaces. Not all targets
6644 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6645
6646<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6647 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6648 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6649 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6650 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6651</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6652
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6653<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6654<p>This loads a value in memory and compares it to a given value. If they are
6655 equal, it stores a new value into the memory.</p>
6656
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6657<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6658<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6659 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6660 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6661 this integer type. While any bit width integer may be used, targets may only
6662 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6663
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6664<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6665<p>This entire intrinsic must be executed atomically. It first loads the value
6666 in memory pointed to by <tt>ptr</tt> and compares it with the
6667 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6668 memory. The loaded value is yielded in all cases. This provides the
6669 equivalent of an atomic compare-and-swap operation within the SSA
6670 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6671
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6672<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6673<pre>
6674%ptr = malloc i32
6675 store i32 4, %ptr
6676
6677%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6678%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6679 <i>; yields {i32}:result1 = 4</i>
6680%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6681%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6682
6683%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6684%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6685 <i>; yields {i32}:result2 = 8</i>
6686%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6687
6688%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6689</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6690
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6691</div>
6692
6693<!-- _______________________________________________________________________ -->
6694<div class="doc_subsubsection">
6695 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6696</div>
6697<div class="doc_text">
6698<h5>Syntax:</h5>
6699
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6700<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6701 integer bit width. Not all targets support all bit widths however.</p>
6702
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6703<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6704 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6705 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6706 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6707 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6708</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6709
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6710<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6711<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6712 the value from memory. It then stores the value in <tt>val</tt> in the memory
6713 at <tt>ptr</tt>.</p>
6714
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6715<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6716<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6717 the <tt>val</tt> argument and the result must be integers of the same bit
6718 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6719 integer type. The targets may only lower integer representations they
6720 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6721
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6722<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6723<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6724 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6725 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6726
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6727<h5>Examples:</h5>
6728<pre>
6729%ptr = malloc i32
6730 store i32 4, %ptr
6731
6732%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6733%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6734 <i>; yields {i32}:result1 = 4</i>
6735%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6736%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6737
6738%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6739%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6740 <i>; yields {i32}:result2 = 8</i>
6741
6742%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6743%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6744</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6745
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6746</div>
6747
6748<!-- _______________________________________________________________________ -->
6749<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6750 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6751
6752</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6753
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6754<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6755
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6756<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6757<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6758 any integer bit width. Not all targets support all bit widths however.</p>
6759
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6760<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6761 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6762 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6763 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6764 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6765</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6766
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6767<h5>Overview:</h5>
6768<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6769 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6770
6771<h5>Arguments:</h5>
6772<p>The intrinsic takes two arguments, the first a pointer to an integer value
6773 and the second an integer value. The result is also an integer value. These
6774 integer types can have any bit width, but they must all have the same bit
6775 width. The targets may only lower integer representations they support.</p>
6776
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6777<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6778<p>This intrinsic does a series of operations atomically. It first loads the
6779 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6780 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6781
6782<h5>Examples:</h5>
6783<pre>
6784%ptr = malloc i32
6785 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6786%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6787 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6788%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6789 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6790%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6791 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6792%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6793</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6794
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6795</div>
6796
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6797<!-- _______________________________________________________________________ -->
6798<div class="doc_subsubsection">
6799 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6800
6801</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6802
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6803<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6804
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6805<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6806<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6807 any integer bit width and for different address spaces. Not all targets
6808 support all bit widths however.</p>
6809
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6810<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6811 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6812 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6813 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6814 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6815</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6816
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6817<h5>Overview:</h5>
6818<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6819 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6820
6821<h5>Arguments:</h5>
6822<p>The intrinsic takes two arguments, the first a pointer to an integer value
6823 and the second an integer value. The result is also an integer value. These
6824 integer types can have any bit width, but they must all have the same bit
6825 width. The targets may only lower integer representations they support.</p>
6826
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6827<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6828<p>This intrinsic does a series of operations atomically. It first loads the
6829 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6830 result to <tt>ptr</tt>. It yields the original value stored
6831 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6832
6833<h5>Examples:</h5>
6834<pre>
6835%ptr = malloc i32
6836 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6837%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6838 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6839%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6840 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6841%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6842 <i>; yields {i32}:result3 = 2</i>
6843%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6844</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6845
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6846</div>
6847
6848<!-- _______________________________________________________________________ -->
6849<div class="doc_subsubsection">
6850 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6851 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6852 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6853 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6854</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6855
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6856<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6857
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6858<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6859<p>These are overloaded intrinsics. You can
6860 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6861 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6862 bit width and for different address spaces. Not all targets support all bit
6863 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6865<pre>
6866 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6867 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6868 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6869 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6870</pre>
6871
6872<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6873 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6874 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6875 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6876 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6877</pre>
6878
6879<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6880 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6881 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6882 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6883 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6884</pre>
6885
6886<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6887 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6888 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6889 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6890 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6891</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6892
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6893<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6894<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6895 the value stored in memory at <tt>ptr</tt>. It yields the original value
6896 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6897
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898<h5>Arguments:</h5>
6899<p>These intrinsics take two arguments, the first a pointer to an integer value
6900 and the second an integer value. The result is also an integer value. These
6901 integer types can have any bit width, but they must all have the same bit
6902 width. The targets may only lower integer representations they support.</p>
6903
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6904<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905<p>These intrinsics does a series of operations atomically. They first load the
6906 value stored at <tt>ptr</tt>. They then do the bitwise
6907 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6908 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6909
6910<h5>Examples:</h5>
6911<pre>
6912%ptr = malloc i32
6913 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6914%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6915 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6916%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6917 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6918%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6919 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6920%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6921 <i>; yields {i32}:result3 = FF</i>
6922%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6923</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6924
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6925</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6926
6927<!-- _______________________________________________________________________ -->
6928<div class="doc_subsubsection">
6929 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6930 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6931 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6932 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6933</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6935<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6936
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6937<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6939 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6940 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6941 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6942
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943<pre>
6944 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6945 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6946 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6947 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6948</pre>
6949
6950<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6951 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6952 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6953 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6954 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6955</pre>
6956
6957<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6958 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6959 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6960 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6961 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6962</pre>
6963
6964<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6965 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6966 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6967 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6968 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6969</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6970
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6971<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6972<p>These intrinsics takes the signed or unsigned minimum or maximum of
6973 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6974 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6975
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6976<h5>Arguments:</h5>
6977<p>These intrinsics take two arguments, the first a pointer to an integer value
6978 and the second an integer value. The result is also an integer value. These
6979 integer types can have any bit width, but they must all have the same bit
6980 width. The targets may only lower integer representations they support.</p>
6981
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6982<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p>These intrinsics does a series of operations atomically. They first load the
6984 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6985 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6986 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6987
6988<h5>Examples:</h5>
6989<pre>
6990%ptr = malloc i32
6991 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6992%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6993 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6994%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6995 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6996%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6997 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6998%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6999 <i>; yields {i32}:result3 = 8</i>
7000%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7001</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7002
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7003</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7004
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7005
7006<!-- ======================================================================= -->
7007<div class="doc_subsection">
7008 <a name="int_memorymarkers">Memory Use Markers</a>
7009</div>
7010
7011<div class="doc_text">
7012
7013<p>This class of intrinsics exists to information about the lifetime of memory
7014 objects and ranges where variables are immutable.</p>
7015
7016</div>
7017
7018<!-- _______________________________________________________________________ -->
7019<div class="doc_subsubsection">
7020 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7021</div>
7022
7023<div class="doc_text">
7024
7025<h5>Syntax:</h5>
7026<pre>
7027 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7028</pre>
7029
7030<h5>Overview:</h5>
7031<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7032 object's lifetime.</p>
7033
7034<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7035<p>The first argument is a constant integer representing the size of the
7036 object, or -1 if it is variable sized. The second argument is a pointer to
7037 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7038
7039<h5>Semantics:</h5>
7040<p>This intrinsic indicates that before this point in the code, the value of the
7041 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7042 never be used and has an undefined value. A load from the pointer that is
7043 preceded by this intrinsic can be replaced with
7044 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7045
7046</div>
7047
7048<!-- _______________________________________________________________________ -->
7049<div class="doc_subsubsection">
7050 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7051</div>
7052
7053<div class="doc_text">
7054
7055<h5>Syntax:</h5>
7056<pre>
7057 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7058</pre>
7059
7060<h5>Overview:</h5>
7061<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7062 object's lifetime.</p>
7063
7064<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7065<p>The first argument is a constant integer representing the size of the
7066 object, or -1 if it is variable sized. The second argument is a pointer to
7067 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7068
7069<h5>Semantics:</h5>
7070<p>This intrinsic indicates that after this point in the code, the value of the
7071 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7072 never be used and has an undefined value. Any stores into the memory object
7073 following this intrinsic may be removed as dead.
7074
7075</div>
7076
7077<!-- _______________________________________________________________________ -->
7078<div class="doc_subsubsection">
7079 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7080</div>
7081
7082<div class="doc_text">
7083
7084<h5>Syntax:</h5>
7085<pre>
7086 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7087</pre>
7088
7089<h5>Overview:</h5>
7090<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7091 a memory object will not change.</p>
7092
7093<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7094<p>The first argument is a constant integer representing the size of the
7095 object, or -1 if it is variable sized. The second argument is a pointer to
7096 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7097
7098<h5>Semantics:</h5>
7099<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7100 the return value, the referenced memory location is constant and
7101 unchanging.</p>
7102
7103</div>
7104
7105<!-- _______________________________________________________________________ -->
7106<div class="doc_subsubsection">
7107 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7108</div>
7109
7110<div class="doc_text">
7111
7112<h5>Syntax:</h5>
7113<pre>
7114 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7115</pre>
7116
7117<h5>Overview:</h5>
7118<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7119 a memory object are mutable.</p>
7120
7121<h5>Arguments:</h5>
7122<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7123 The second argument is a constant integer representing the size of the
7124 object, or -1 if it is variable sized and the third argument is a pointer
7125 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7126
7127<h5>Semantics:</h5>
7128<p>This intrinsic indicates that the memory is mutable again.</p>
7129
7130</div>
7131
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7132<!-- ======================================================================= -->
7133<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7134 <a name="int_general">General Intrinsics</a>
7135</div>
7136
7137<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7138
7139<p>This class of intrinsics is designed to be generic and has no specific
7140 purpose.</p>
7141
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7142</div>
7143
7144<!-- _______________________________________________________________________ -->
7145<div class="doc_subsubsection">
7146 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7147</div>
7148
7149<div class="doc_text">
7150
7151<h5>Syntax:</h5>
7152<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7153 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]7154</pre>
7155
7156<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7157<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7158
7159<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160<p>The first argument is a pointer to a value, the second is a pointer to a
7161 global string, the third is a pointer to a global string which is the source
7162 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7163
7164<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7165<p>This intrinsic allows annotation of local variables with arbitrary strings.
7166 This can be useful for special purpose optimizations that want to look for
7167 these annotations. These have no other defined use, they are ignored by code
7168 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7169
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7170</div>
7171
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7172<!-- _______________________________________________________________________ -->
7173<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7174 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7175</div>
7176
7177<div class="doc_text">
7178
7179<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7180<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7181 any integer bit width.</p>
7182
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7183<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7184 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7185 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7186 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7187 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7188 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]7189</pre>
7190
7191<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7192<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7193
7194<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7195<p>The first argument is an integer value (result of some expression), the
7196 second is a pointer to a global string, the third is a pointer to a global
7197 string which is the source file name, and the last argument is the line
7198 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7199
7200<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7201<p>This intrinsic allows annotations to be put on arbitrary expressions with
7202 arbitrary strings. This can be useful for special purpose optimizations that
7203 want to look for these annotations. These have no other defined use, they
7204 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7205
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7206</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7207
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7208<!-- _______________________________________________________________________ -->
7209<div class="doc_subsubsection">
7210 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7211</div>
7212
7213<div class="doc_text">
7214
7215<h5>Syntax:</h5>
7216<pre>
7217 declare void @llvm.trap()
7218</pre>
7219
7220<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7222
7223<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7224<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7225
7226<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227<p>This intrinsics is lowered to the target dependent trap instruction. If the
7228 target does not have a trap instruction, this intrinsic will be lowered to
7229 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7230
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7231</div>
7232
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7233<!-- _______________________________________________________________________ -->
7234<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7235 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7236</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7237
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7238<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7239
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7240<h5>Syntax:</h5>
7241<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7242 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7243</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7244
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7245<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7246<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7247 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7248 ensure that it is placed on the stack before local variables.</p>
7249
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7250<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7251<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7252 arguments. The first argument is the value loaded from the stack
7253 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7254 that has enough space to hold the value of the guard.</p>
7255
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7256<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7257<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7258 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7259 stack. This is to ensure that if a local variable on the stack is
7260 overwritten, it will destroy the value of the guard. When the function exits,
7261 the guard on the stack is checked against the original guard. If they're
7262 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7263 function.</p>
7264
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7265</div>
7266
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7267<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7268<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7269<address>
7270 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7271 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7272 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7273 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7274
7275 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7276 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7277 Last modified: $Date$
7278</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7279
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7280</body>
7281</html>