Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / ad8b58b2ac96b94b3cbd6afedfcd6a5c66fd3f06 / . / llvm / docs / LangRef.html
blob: ed4e4d58214d818045aa2542a1adfc94b87c75ce [file] [log] [blame]
Misha Brukmanc501f552004-03-01 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 Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 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">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 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>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
112 <ol>
113 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]114 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
115 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]116 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
117 Global Variable</a></li>
118 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
119 Global Variable</a></li>
120 </ol>
121 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]122 <li><a href="#instref">Instruction Reference</a>
123 <ol>
124 <li><a href="#terminators">Terminator Instructions</a>
125 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
127 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]144 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
145 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
146 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]147 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
148 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
149 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]154 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
155 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
156 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]162 <li><a href="#vectorops">Vector Operations</a>
163 <ol>
164 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
165 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
166 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]169 <li><a href="#aggregateops">Aggregate Operations</a>
170 <ol>
171 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
172 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
173 </ol>
174 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]177 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
178 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
179 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
180 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
181 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
182 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]187 <ol>
188 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
189 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]193 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
195 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]197 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
198 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]204 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
205 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
221 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]226 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
228 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
235 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
236 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
237 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
238 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]249 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]252 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]260 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
262 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]267 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
270 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]272 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]273 </ol>
274 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]277 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
278 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]279 </ol>
280 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
291 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
292 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
293 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
294 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
295 </ol>
296 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]309 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]310 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]311 </ol>
312 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]313</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]314
315<div class="doc_author">
316 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
317 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]318</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]319
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]320<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]321<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]323
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]324<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]325
326<p>This document is a reference manual for the LLVM assembly language. LLVM is
327 a Static Single Assignment (SSA) based representation that provides type
328 safety, low-level operations, flexibility, and the capability of representing
329 'all' high-level languages cleanly. It is the common code representation
330 used throughout all phases of the LLVM compilation strategy.</p>
331
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]332</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]334<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]335<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]337
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]338<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]340<p>The LLVM code representation is designed to be used in three different forms:
341 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
342 for fast loading by a Just-In-Time compiler), and as a human readable
343 assembly language representation. This allows LLVM to provide a powerful
344 intermediate representation for efficient compiler transformations and
345 analysis, while providing a natural means to debug and visualize the
346 transformations. The three different forms of LLVM are all equivalent. This
347 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]348
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]349<p>The LLVM representation aims to be light-weight and low-level while being
350 expressive, typed, and extensible at the same time. It aims to be a
351 "universal IR" of sorts, by being at a low enough level that high-level ideas
352 may be cleanly mapped to it (similar to how microprocessors are "universal
353 IR's", allowing many source languages to be mapped to them). By providing
354 type information, LLVM can be used as the target of optimizations: for
355 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]356 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]357 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]359<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]360<h4>
361 <a name="wellformed">Well-Formedness</a>
362</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]364<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]366<p>It is important to note that this document describes 'well formed' LLVM
367 assembly language. There is a difference between what the parser accepts and
368 what is considered 'well formed'. For example, the following instruction is
369 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]371<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]372%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373</pre>
374
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]375<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
376 LLVM infrastructure provides a verification pass that may be used to verify
377 that an LLVM module is well formed. This pass is automatically run by the
378 parser after parsing input assembly and by the optimizer before it outputs
379 bitcode. The violations pointed out by the verifier pass indicate bugs in
380 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]381
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]382</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]383
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]384</div>
385
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]388<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]389<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]391
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]392<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]393
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]400<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]415</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]435
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]436<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440</pre>
441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]442<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446</pre>
447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]448<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]453%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454</pre>
455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]459<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]466 <li>Unnamed temporaries are numbered sequentially</li>
467</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]474</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]475
476<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]477<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]478<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]479<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]480<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]481<h3>
482 <a name="modulestructure">Module Structure</a>
483</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]484
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]485<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]531<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]532 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]533</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]534
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]535<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]637
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]671 other than <tt>external</tt>, <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]673
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]680<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]682</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]683
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]684<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]753<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]755</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]756
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]757<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]787<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]789</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]791<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]818<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]820</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]821
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]822<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]823
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]886<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]887 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]888</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]889
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]890<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]891
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]919<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]928<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]935 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]936
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]949<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]950 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]951</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]953<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]968<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]969 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]970</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]971
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]972<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]973
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]991<h3>
992 <a name="paramattrs">Parameter Attributes</a>
993</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]994
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]995<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]996
997<p>The return type and each parameter of a function type may have a set of
998 <i>parameter attributes</i> associated with them. Parameter attributes are
999 used to communicate additional information about the result or parameters of
1000 a function. Parameter attributes are considered to be part of the function,
1001 not of the function type, so functions with different parameter attributes
1002 can have the same function type.</p>
1003
1004<p>Parameter attributes are simple keywords that follow the type specified. If
1005 multiple parameter attributes are needed, they are space separated. For
1006 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1007
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1008<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1009declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1010declare i32 @atoi(i8 zeroext)
1011declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1012</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1014<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1015 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1016
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1020 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1021 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1022 should be zero-extended to the extent required by the target's ABI (which
1023 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1024 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1025
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1028 should be sign-extended to the extent required by the target's ABI (which
1029 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1030 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1031
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates that this parameter or return value should be treated in a
1034 special target-dependent fashion during while emitting code for a function
1035 call or return (usually, by putting it in a register as opposed to memory,
1036 though some targets use it to distinguish between two different kinds of
1037 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1038
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1039 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1040 <dd><p>This indicates that the pointer parameter should really be passed by
1041 value to the function. The attribute implies that a hidden copy of the
1042 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1043 is made between the caller and the callee, so the callee is unable to
1044 modify the value in the callee. This attribute is only valid on LLVM
1045 pointer arguments. It is generally used to pass structs and arrays by
1046 value, but is also valid on pointers to scalars. The copy is considered
1047 to belong to the caller not the callee (for example,
1048 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1049 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1050 values.</p>
1051
1052 <p>The byval attribute also supports specifying an alignment with
1053 the align attribute. It indicates the alignment of the stack slot to
1054 form and the known alignment of the pointer specified to the call site. If
1055 the alignment is not specified, then the code generator makes a
1056 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1057
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1058 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the pointer parameter specifies the address of a
1060 structure that is the return value of the function in the source program.
1061 This pointer must be guaranteed by the caller to be valid: loads and
1062 stores to the structure may be assumed by the callee to not to trap. This
1063 may only be applied to the first parameter. This is not a valid attribute
1064 for return values. </dd>
1065
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1066 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1067 <dd>This indicates that pointer values
1068 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1069 value do not alias pointer values which are not <i>based</i> on it,
1070 ignoring certain "irrelevant" dependencies.
1071 For a call to the parent function, dependencies between memory
1072 references from before or after the call and from those during the call
1073 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1074 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1075 The caller shares the responsibility with the callee for ensuring that
1076 these requirements are met.
1077 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1078 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1079<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1080 Note that this definition of <tt>noalias</tt> is intentionally
1081 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1082 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1083<br>
1084 For function return values, C99's <tt>restrict</tt> is not meaningful,
1085 while LLVM's <tt>noalias</tt> is.
1086 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1087
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1088 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This indicates that the callee does not make any copies of the pointer
1090 that outlive the callee itself. This is not a valid attribute for return
1091 values.</dd>
1092
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1093 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This indicates that the pointer parameter can be excised using the
1095 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1096 attribute for return values.</dd>
1097</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1098
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1102<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1103 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1104</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1105
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1106<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1108<p>Each function may specify a garbage collector name, which is simply a
1109 string:</p>
1110
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1111<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1112define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1114
1115<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1116 collector which will cause the compiler to alter its output in order to
1117 support the named garbage collection algorithm.</p>
1118
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1119</div>
1120
1121<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1122<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1123 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1124</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1125
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1126<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1127
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1128<p>Function attributes are set to communicate additional information about a
1129 function. Function attributes are considered to be part of the function, not
1130 of the function type, so functions with different parameter attributes can
1131 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1132
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133<p>Function attributes are simple keywords that follow the type specified. If
1134 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1135
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1136<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1137define void @f() noinline { ... }
1138define void @f() alwaysinline { ... }
1139define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1140define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1141</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1142
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1143<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1144 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1145 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1146 the backend should forcibly align the stack pointer. Specify the
1147 desired alignment, which must be a power of two, in parentheses.
1148
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This attribute indicates that the inliner should attempt to inline this
1151 function into callers whenever possible, ignoring any active inlining size
1152 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1153
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1154 <dt><tt><b>nonlazybind</b></tt></dt>
1155 <dd>This attribute suppresses lazy symbol binding for the function. This
1156 may make calls to the function faster, at the cost of extra program
1157 startup time if the function is not called during program startup.</dd>
1158
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1159 <dt><tt><b>inlinehint</b></tt></dt>
1160 <dd>This attribute indicates that the source code contained a hint that inlining
1161 this function is desirable (such as the "inline" keyword in C/C++). It
1162 is just a hint; it imposes no requirements on the inliner.</dd>
1163
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1164 <dt><tt><b>naked</b></tt></dt>
1165 <dd>This attribute disables prologue / epilogue emission for the function.
1166 This can have very system-specific consequences.</dd>
1167
1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the inliner should never inline this
1173 function in any situation. This attribute may not be used together with
1174 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1175
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>noredzone</b></tt></dt>
1177 <dd>This attribute indicates that the code generator should not use a red
1178 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1179
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This function attribute indicates that the function never returns
1182 normally. This produces undefined behavior at runtime if the function
1183 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1184
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1185 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1186 <dd>This function attribute indicates that the function never returns with an
1187 unwind or exceptional control flow. If the function does unwind, its
1188 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1189
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1190 <dt><tt><b>optsize</b></tt></dt>
1191 <dd>This attribute suggests that optimization passes and code generator passes
1192 make choices that keep the code size of this function low, and otherwise
1193 do optimizations specifically to reduce code size.</dd>
1194
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1195 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1196 <dd>This attribute indicates that the function computes its result (or decides
1197 to unwind an exception) based strictly on its arguments, without
1198 dereferencing any pointer arguments or otherwise accessing any mutable
1199 state (e.g. memory, control registers, etc) visible to caller functions.
1200 It does not write through any pointer arguments
1201 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1202 changes any state visible to callers. This means that it cannot unwind
1203 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1204 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1205
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1206 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1207 <dd>This attribute indicates that the function does not write through any
1208 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1209 arguments) or otherwise modify any state (e.g. memory, control registers,
1210 etc) visible to caller functions. It may dereference pointer arguments
1211 and read state that may be set in the caller. A readonly function always
1212 returns the same value (or unwinds an exception identically) when called
1213 with the same set of arguments and global state. It cannot unwind an
1214 exception by calling the <tt>C++</tt> exception throwing methods, but may
1215 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1216
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1217 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1218 <dd>This attribute indicates that the function should emit a stack smashing
1219 protector. It is in the form of a "canary"&mdash;a random value placed on
1220 the stack before the local variables that's checked upon return from the
1221 function to see if it has been overwritten. A heuristic is used to
1222 determine if a function needs stack protectors or not.<br>
1223<br>
1224 If a function that has an <tt>ssp</tt> attribute is inlined into a
1225 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1226 function will have an <tt>ssp</tt> attribute.</dd>
1227
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1228 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1229 <dd>This attribute indicates that the function should <em>always</em> emit a
1230 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1231 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1232<br>
1233 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1234 function that doesn't have an <tt>sspreq</tt> attribute or which has
1235 an <tt>ssp</tt> attribute, then the resulting function will have
1236 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1237
1238 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1239 <dd>This attribute indicates that the ABI being targeted requires that
1240 an unwind table entry be produce for this function even if we can
1241 show that no exceptions passes by it. This is normally the case for
1242 the ELF x86-64 abi, but it can be disabled for some compilation
1243 units.</dd>
1244
Rafael Espindolacc349c82011-10-03 14:45:37 +0000[diff] [blame]1245 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1246 <dd>This attribute indicates that this function can return
1247 twice. The C <code>setjmp</code> is an example of such a function.
1248 The compiler disables some optimizations (like tail calls) in the caller of
1249 these functions.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1250</dl>
1251
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1252</div>
1253
1254<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1255<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1256 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1257</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1258
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1259<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1260
1261<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1262 the GCC "file scope inline asm" blocks. These blocks are internally
1263 concatenated by LLVM and treated as a single unit, but may be separated in
1264 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1265
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1266<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1267module asm "inline asm code goes here"
1268module asm "more can go here"
1269</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1270
1271<p>The strings can contain any character by escaping non-printable characters.
1272 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1273 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1274
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1275<p>The inline asm code is simply printed to the machine code .s file when
1276 assembly code is generated.</p>
1277
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1278</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1279
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1280<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1281<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1282 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1283</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1284
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1285<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1286
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1287<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1288 data is to be laid out in memory. The syntax for the data layout is
1289 simply:</p>
1290
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1291<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1292target datalayout = "<i>layout specification</i>"
1293</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>The <i>layout specification</i> consists of a list of specifications
1296 separated by the minus sign character ('-'). Each specification starts with
1297 a letter and may include other information after the letter to define some
1298 aspect of the data layout. The specifications accepted are as follows:</p>
1299
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1300<dl>
1301 <dt><tt>E</tt></dt>
1302 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1303 bits with the most significance have the lowest address location.</dd>
1304
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1305 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1306 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307 the bits with the least significance have the lowest address
1308 location.</dd>
1309
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1310 <dt><tt>S<i>size</i></tt></dt>
1311 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1312 of stack variables is limited to the natural stack alignment to avoid
1313 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1314 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1315 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1318 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 <i>preferred</i> alignments. All sizes are in bits. Specifying
1320 the <i>pref</i> alignment is optional. If omitted, the
1321 preceding <tt>:</tt> should be omitted too.</dd>
1322
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1323 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1326
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1327 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1328 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1329 <i>size</i>.</dd>
1330
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1331 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1332 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1333 <i>size</i>. Only values of <i>size</i> that are supported by the target
1334 will work. 32 (float) and 64 (double) are supported on all targets;
1335 80 or 128 (different flavors of long double) are also supported on some
1336 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1339 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1340 <i>size</i>.</dd>
1341
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1342 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1343 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1344 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1345
1346 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1347 <dd>This specifies a set of native integer widths for the target CPU
1348 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1349 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1350 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1351 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1352</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1353
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1354<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1355 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1356 specifications in the <tt>datalayout</tt> keyword. The default specifications
1357 are given in this list:</p>
1358
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1359<ul>
1360 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1361 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1362 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1363 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1364 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1365 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1366 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1367 alignment of 64-bits</li>
1368 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1369 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1370 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1371 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1372 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1373 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1374</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1375
1376<p>When LLVM is determining the alignment for a given type, it uses the
1377 following rules:</p>
1378
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1379<ol>
1380 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1381 specification is used.</li>
1382
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1383 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1384 smallest integer type that is larger than the bitwidth of the sought type
1385 is used. If none of the specifications are larger than the bitwidth then
1386 the the largest integer type is used. For example, given the default
1387 specifications above, the i7 type will use the alignment of i8 (next
1388 largest) while both i65 and i256 will use the alignment of i64 (largest
1389 specified).</li>
1390
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1391 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1392 largest vector type that is smaller than the sought vector type will be
1393 used as a fall back. This happens because &lt;128 x double&gt; can be
1394 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1395</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1396
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1397<p>The function of the data layout string may not be what you expect. Notably,
1398 this is not a specification from the frontend of what alignment the code
1399 generator should use.</p>
1400
1401<p>Instead, if specified, the target data layout is required to match what the
1402 ultimate <em>code generator</em> expects. This string is used by the
1403 mid-level optimizers to
1404 improve code, and this only works if it matches what the ultimate code
1405 generator uses. If you would like to generate IR that does not embed this
1406 target-specific detail into the IR, then you don't have to specify the
1407 string. This will disable some optimizations that require precise layout
1408 information, but this also prevents those optimizations from introducing
1409 target specificity into the IR.</p>
1410
1411
1412
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1413</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1414
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1415<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1416<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1417 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1418</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1419
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1420<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1421
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1422<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1423with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1424is undefined. Pointer values are associated with address ranges
1425according to the following rules:</p>
1426
1427<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1428 <li>A pointer value is associated with the addresses associated with
1429 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1430 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1431 range of the variable's storage.</li>
1432 <li>The result value of an allocation instruction is associated with
1433 the address range of the allocated storage.</li>
1434 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1435 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1436 <li>An integer constant other than zero or a pointer value returned
1437 from a function not defined within LLVM may be associated with address
1438 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1439 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1440 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1441</ul>
1442
1443<p>A pointer value is <i>based</i> on another pointer value according
1444 to the following rules:</p>
1445
1446<ul>
1447 <li>A pointer value formed from a
1448 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1449 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1450 <li>The result value of a
1451 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1452 of the <tt>bitcast</tt>.</li>
1453 <li>A pointer value formed by an
1454 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1455 pointer values that contribute (directly or indirectly) to the
1456 computation of the pointer's value.</li>
1457 <li>The "<i>based</i> on" relationship is transitive.</li>
1458</ul>
1459
1460<p>Note that this definition of <i>"based"</i> is intentionally
1461 similar to the definition of <i>"based"</i> in C99, though it is
1462 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1463
1464<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1465<tt><a href="#i_load">load</a></tt> merely indicates the size and
1466alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1467interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1468<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1469and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1470
1471<p>Consequently, type-based alias analysis, aka TBAA, aka
1472<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1473LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1474additional information which specialized optimization passes may use
1475to implement type-based alias analysis.</p>
1476
1477</div>
1478
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1479<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1480<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1481 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1482</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1483
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1484<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1485
1486<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1487href="#i_store"><tt>store</tt></a>s, and <a
1488href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1489The optimizers must not change the number of volatile operations or change their
1490order of execution relative to other volatile operations. The optimizers
1491<i>may</i> change the order of volatile operations relative to non-volatile
1492operations. This is not Java's "volatile" and has no cross-thread
1493synchronization behavior.</p>
1494
1495</div>
1496
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1497<!-- ======================================================================= -->
1498<h3>
1499 <a name="memmodel">Memory Model for Concurrent Operations</a>
1500</h3>
1501
1502<div>
1503
1504<p>The LLVM IR does not define any way to start parallel threads of execution
1505or to register signal handlers. Nonetheless, there are platform-specific
1506ways to create them, and we define LLVM IR's behavior in their presence. This
1507model is inspired by the C++0x memory model.</p>
1508
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1509<p>For a more informal introduction to this model, see the
1510<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1511
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1512<p>We define a <i>happens-before</i> partial order as the least partial order
1513that</p>
1514<ul>
1515 <li>Is a superset of single-thread program order, and</li>
1516 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1517 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1518 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1519 creation, thread joining, etc., and by atomic instructions.
1520 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1521 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1522</ul>
1523
1524<p>Note that program order does not introduce <i>happens-before</i> edges
1525between a thread and signals executing inside that thread.</p>
1526
1527<p>Every (defined) read operation (load instructions, memcpy, atomic
1528loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1529(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1530stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1531initialized globals are considered to have a write of the initializer which is
1532atomic and happens before any other read or write of the memory in question.
1533For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1534any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1535
1536<ul>
1537 <li>If <var>write<sub>1</sub></var> happens before
1538 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1539 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1540 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1541 <li>If <var>R<sub>byte</sub></var> happens before
1542 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1543 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1544</ul>
1545
1546<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1547<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1548 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1549 is supposed to give guarantees which can support
1550 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1551 addresses which do not behave like normal memory. It does not generally
1552 provide cross-thread synchronization.)
1553 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1554 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1555 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1556 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1557 <var>R<sub>byte</sub></var> returns the value written by that
1558 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1559 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1560 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1561 values written. See the <a href="#ordering">Atomic Memory Ordering
1562 Constraints</a> section for additional constraints on how the choice
1563 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1564 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1565</ul>
1566
1567<p><var>R</var> returns the value composed of the series of bytes it read.
1568This implies that some bytes within the value may be <tt>undef</tt>
1569<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1570defines the semantics of the operation; it doesn't mean that targets will
1571emit more than one instruction to read the series of bytes.</p>
1572
1573<p>Note that in cases where none of the atomic intrinsics are used, this model
1574places only one restriction on IR transformations on top of what is required
1575for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1576otherwise be stored is not allowed in general. (Specifically, in the case
1577where another thread might write to and read from an address, introducing a
1578store can change a load that may see exactly one write into a load that may
1579see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1580
1581<!-- FIXME: This model assumes all targets where concurrency is relevant have
1582a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1583none of the backends currently in the tree fall into this category; however,
1584there might be targets which care. If there are, we want a paragraph
1585like the following:
1586
1587Targets may specify that stores narrower than a certain width are not
1588available; on such a target, for the purposes of this model, treat any
1589non-atomic write with an alignment or width less than the minimum width
1590as if it writes to the relevant surrounding bytes.
1591-->
1592
1593</div>
1594
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1595<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1596<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1597 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1598</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1599
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1600<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1601
1602<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1603<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1604<a href="#i_fence"><code>fence</code></a>,
1605<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1606<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1607that determines which other atomic instructions on the same address they
1608<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1609but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1610check those specs (see spec references in the
1611<a href="Atomic.html#introduction">atomics guide</a>).
1612<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1613treat these orderings somewhat differently since they don't take an address.
1614See that instruction's documentation for details.</p>
1615
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1616<p>For a simpler introduction to the ordering constraints, see the
1617<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1618
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1619<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1620<dt><code>unordered</code></dt>
1621<dd>The set of values that can be read is governed by the happens-before
1622partial order. A value cannot be read unless some operation wrote it.
1623This is intended to provide a guarantee strong enough to model Java's
1624non-volatile shared variables. This ordering cannot be specified for
1625read-modify-write operations; it is not strong enough to make them atomic
1626in any interesting way.</dd>
1627<dt><code>monotonic</code></dt>
1628<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1629total order for modifications by <code>monotonic</code> operations on each
1630address. All modification orders must be compatible with the happens-before
1631order. There is no guarantee that the modification orders can be combined to
1632a global total order for the whole program (and this often will not be
1633possible). The read in an atomic read-modify-write operation
1634(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1635<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1636reads the value in the modification order immediately before the value it
1637writes. If one atomic read happens before another atomic read of the same
1638address, the later read must see the same value or a later value in the
1639address's modification order. This disallows reordering of
1640<code>monotonic</code> (or stronger) operations on the same address. If an
1641address is written <code>monotonic</code>ally by one thread, and other threads
1642<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1643eventually see the write. This corresponds to the C++0x/C1x
1644<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1645<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1646<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1647a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1648operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1649<dt><code>release</code></dt>
1650<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1651writes a value which is subsequently read by an <code>acquire</code> operation,
1652it <i>synchronizes-with</i> that operation. (This isn't a complete
1653description; see the C++0x definition of a release sequence.) This corresponds
1654to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1655<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1656<code>acquire</code> and <code>release</code> operation on its address.
1657This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1658<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1659<dd>In addition to the guarantees of <code>acq_rel</code>
1660(<code>acquire</code> for an operation which only reads, <code>release</code>
1661for an operation which only writes), there is a global total order on all
1662sequentially-consistent operations on all addresses, which is consistent with
1663the <i>happens-before</i> partial order and with the modification orders of
1664all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1665preceding write to the same address in this global order. This corresponds
1666to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1667</dl>
1668
1669<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1670it only <i>synchronizes with</i> or participates in modification and seq_cst
1671total orderings with other operations running in the same thread (for example,
1672in signal handlers).</p>
1673
1674</div>
1675
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1676</div>
1677
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1678<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1679<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1680<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1681
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1682<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1683
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1684<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1685 intermediate representation. Being typed enables a number of optimizations
1686 to be performed on the intermediate representation directly, without having
1687 to do extra analyses on the side before the transformation. A strong type
1688 system makes it easier to read the generated code and enables novel analyses
1689 and transformations that are not feasible to perform on normal three address
1690 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1691
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1692<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1693<h3>
1694 <a name="t_classifications">Type Classifications</a>
1695</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1696
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1697<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1698
1699<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1700
1701<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1702 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1703 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1704 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1705 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1706 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1707 </tr>
1708 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1709 <td><a href="#t_floating">floating point</a></td>
1710 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1711 </tr>
1712 <tr>
1713 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1714 <td><a href="#t_integer">integer</a>,
1715 <a href="#t_floating">floating point</a>,
1716 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1717 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1718 <a href="#t_struct">structure</a>,
1719 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1720 <a href="#t_label">label</a>,
1721 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1722 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1723 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1724 <tr>
1725 <td><a href="#t_primitive">primitive</a></td>
1726 <td><a href="#t_label">label</a>,
1727 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1728 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1729 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1730 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1732 </tr>
1733 <tr>
1734 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1735 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1736 <a href="#t_function">function</a>,
1737 <a href="#t_pointer">pointer</a>,
1738 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1739 <a href="#t_vector">vector</a>,
1740 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1741 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1742 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1743 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1744</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1745
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1746<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1747 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1748 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1749
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1753<h3>
1754 <a name="t_primitive">Primitive Types</a>
1755</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1756
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1757<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1758
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1759<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1760 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1761
1762<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1763<h4>
1764 <a name="t_integer">Integer Type</a>
1765</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1766
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1767<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1768
1769<h5>Overview:</h5>
1770<p>The integer type is a very simple type that simply specifies an arbitrary
1771 bit width for the integer type desired. Any bit width from 1 bit to
1772 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1773
1774<h5>Syntax:</h5>
1775<pre>
1776 iN
1777</pre>
1778
1779<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1780 value.</p>
1781
1782<h5>Examples:</h5>
1783<table class="layout">
1784 <tr class="layout">
1785 <td class="left"><tt>i1</tt></td>
1786 <td class="left">a single-bit integer.</td>
1787 </tr>
1788 <tr class="layout">
1789 <td class="left"><tt>i32</tt></td>
1790 <td class="left">a 32-bit integer.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>i1942652</tt></td>
1794 <td class="left">a really big integer of over 1 million bits.</td>
1795 </tr>
1796</table>
1797
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1798</div>
1799
1800<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1801<h4>
1802 <a name="t_floating">Floating Point Types</a>
1803</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1804
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1805<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1806
1807<table>
1808 <tbody>
1809 <tr><th>Type</th><th>Description</th></tr>
1810 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1811 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1812 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1813 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1814 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1815 </tbody>
1816</table>
1817
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1818</div>
1819
1820<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1821<h4>
1822 <a name="t_x86mmx">X86mmx Type</a>
1823</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1824
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1825<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1826
1827<h5>Overview:</h5>
1828<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1829
1830<h5>Syntax:</h5>
1831<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1832 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1833</pre>
1834
1835</div>
1836
1837<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1838<h4>
1839 <a name="t_void">Void Type</a>
1840</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1841
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1842<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1843
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1844<h5>Overview:</h5>
1845<p>The void type does not represent any value and has no size.</p>
1846
1847<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1848<pre>
1849 void
1850</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1851
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1852</div>
1853
1854<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1855<h4>
1856 <a name="t_label">Label Type</a>
1857</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1858
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1859<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1860
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1861<h5>Overview:</h5>
1862<p>The label type represents code labels.</p>
1863
1864<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1865<pre>
1866 label
1867</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_metadata">Metadata Type</a>
1874</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1875
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1877
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1878<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1879<p>The metadata type represents embedded metadata. No derived types may be
1880 created from metadata except for <a href="#t_function">function</a>
1881 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1882
1883<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1884<pre>
1885 metadata
1886</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1887
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1888</div>
1889
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1890</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1891
1892<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1893<h3>
1894 <a name="t_derived">Derived Types</a>
1895</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1896
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1897<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1898
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1899<p>The real power in LLVM comes from the derived types in the system. This is
1900 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1901 useful types. Each of these types contain one or more element types which
1902 may be a primitive type, or another derived type. For example, it is
1903 possible to have a two dimensional array, using an array as the element type
1904 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1905
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1906<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1907<h4>
1908 <a name="t_aggregate">Aggregate Types</a>
1909</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1910
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1911<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1912
1913<p>Aggregate Types are a subset of derived types that can contain multiple
1914 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1915 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1916 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1917
1918</div>
1919
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1920<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1921<h4>
1922 <a name="t_array">Array Type</a>
1923</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1924
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1925<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1927<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1928<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1929 sequentially in memory. The array type requires a size (number of elements)
1930 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1931
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1932<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1933<pre>
1934 [&lt;# elements&gt; x &lt;elementtype&gt;]
1935</pre>
1936
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1937<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1938 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1939
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1940<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1941<table class="layout">
1942 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1943 <td class="left"><tt>[40 x i32]</tt></td>
1944 <td class="left">Array of 40 32-bit integer values.</td>
1945 </tr>
1946 <tr class="layout">
1947 <td class="left"><tt>[41 x i32]</tt></td>
1948 <td class="left">Array of 41 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>[4 x i8]</tt></td>
1952 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1953 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1954</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1955<p>Here are some examples of multidimensional arrays:</p>
1956<table class="layout">
1957 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1958 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1959 <td class="left">3x4 array of 32-bit integer values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1963 <td class="left">12x10 array of single precision floating point values.</td>
1964 </tr>
1965 <tr class="layout">
1966 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1967 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1968 </tr>
1969</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1970
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1971<p>There is no restriction on indexing beyond the end of the array implied by
1972 a static type (though there are restrictions on indexing beyond the bounds
1973 of an allocated object in some cases). This means that single-dimension
1974 'variable sized array' addressing can be implemented in LLVM with a zero
1975 length array type. An implementation of 'pascal style arrays' in LLVM could
1976 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1977
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1978</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1980<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1981<h4>
1982 <a name="t_function">Function Type</a>
1983</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1984
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1985<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1986
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988<p>The function type can be thought of as a function signature. It consists of
1989 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1990 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1991
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1992<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1993<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1994 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1995</pre>
1996
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1997<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1998 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1999 which indicates that the function takes a variable number of arguments.
2000 Variable argument functions can access their arguments with
2001 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2002 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2003 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2004
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2005<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2006<table class="layout">
2007 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2008 <td class="left"><tt>i32 (i32)</tt></td>
2009 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2010 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2011 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2012 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2013 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2014 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2015 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2016 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2017 </td>
2018 </tr><tr class="layout">
2019 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2020 <td class="left">A vararg function that takes at least one
2021 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2022 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2023 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2024 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2025 </tr><tr class="layout">
2026 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2027 <td class="left">A function taking an <tt>i32</tt>, returning a
2028 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2029 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2030 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2031</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2032
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2033</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2034
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2035<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2036<h4>
2037 <a name="t_struct">Structure Type</a>
2038</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2039
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2040<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2041
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2042<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2043<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2044 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2045
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2046<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2047 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2048 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2049 Structures in registers are accessed using the
2050 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2051 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2052
2053<p>Structures may optionally be "packed" structures, which indicate that the
2054 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2055 the elements. In non-packed structs, padding between field types is inserted
2056 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2057 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2058
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2059<p>Structures can either be "literal" or "identified". A literal structure is
2060 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2061 types are always defined at the top level with a name. Literal types are
2062 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2063 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2064 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2065</p>
2066
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2067<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2068<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2069 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2070 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2071</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2072
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2073<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2074<table class="layout">
2075 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2076 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2077 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2078 </tr>
2079 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2080 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2081 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2082 second element is a <a href="#t_pointer">pointer</a> to a
2083 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2084 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2085 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2086 <tr class="layout">
2087 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2088 <td class="left">A packed struct known to be 5 bytes in size.</td>
2089 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2090</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2091
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2092</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2093
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2094<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2095<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2096 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2097</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2098
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2099<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2100
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2101<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2102<p>Opaque structure types are used to represent named structure types that do
2103 not have a body specified. This corresponds (for example) to the C notion of
2104 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2105
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2106<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2107<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2108 %X = type opaque
2109 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2110</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2111
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2112<h5>Examples:</h5>
2113<table class="layout">
2114 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2115 <td class="left"><tt>opaque</tt></td>
2116 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2117 </tr>
2118</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2119
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2120</div>
2121
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2122
2123
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2124<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2125<h4>
2126 <a name="t_pointer">Pointer Type</a>
2127</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2129<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2130
2131<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2132<p>The pointer type is used to specify memory locations.
2133 Pointers are commonly used to reference objects in memory.</p>
2134
2135<p>Pointer types may have an optional address space attribute defining the
2136 numbered address space where the pointed-to object resides. The default
2137 address space is number zero. The semantics of non-zero address
2138 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2139
2140<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2141 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2142
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2143<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2144<pre>
2145 &lt;type&gt; *
2146</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2147
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2148<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2149<table class="layout">
2150 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2151 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2152 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2153 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2154 </tr>
2155 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2156 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2157 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2158 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2159 <tt>i32</tt>.</td>
2160 </tr>
2161 <tr class="layout">
2162 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2163 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2164 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2165 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2166</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2167
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2168</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2169
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2170<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2171<h4>
2172 <a name="t_vector">Vector Type</a>
2173</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2174
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2175<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2176
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2177<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2178<p>A vector type is a simple derived type that represents a vector of elements.
2179 Vector types are used when multiple primitive data are operated in parallel
2180 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2181 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2182 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2183
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2184<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2185<pre>
2186 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2187</pre>
2188
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2189<p>The number of elements is a constant integer value larger than 0; elementtype
2190 may be any integer or floating point type. Vectors of size zero are not
2191 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2192
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2193<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2194<table class="layout">
2195 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2196 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2197 <td class="left">Vector of 4 32-bit integer values.</td>
2198 </tr>
2199 <tr class="layout">
2200 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2201 <td class="left">Vector of 8 32-bit floating-point values.</td>
2202 </tr>
2203 <tr class="layout">
2204 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2205 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2206 </tr>
2207</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2208
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2209</div>
2210
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2211</div>
2212
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2213</div>
2214
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2215<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2216<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2217<!-- *********************************************************************** -->
2218
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2219<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2220
2221<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2222 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2223
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2224<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2225<h3>
2226 <a name="simpleconstants">Simple Constants</a>
2227</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2228
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2229<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2230
2231<dl>
2232 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2233 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2234 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2235
2236 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2237 <dd>Standard integers (such as '4') are constants of
2238 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2239 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2240
2241 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2242 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2243 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2244 notation (see below). The assembler requires the exact decimal value of a
2245 floating-point constant. For example, the assembler accepts 1.25 but
2246 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2247 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2248
2249 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2250 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2251 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2252</dl>
2253
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2254<p>The one non-intuitive notation for constants is the hexadecimal form of
2255 floating point constants. For example, the form '<tt>double
2256 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2257 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2258 constants are required (and the only time that they are generated by the
2259 disassembler) is when a floating point constant must be emitted but it cannot
2260 be represented as a decimal floating point number in a reasonable number of
2261 digits. For example, NaN's, infinities, and other special values are
2262 represented in their IEEE hexadecimal format so that assembly and disassembly
2263 do not cause any bits to change in the constants.</p>
2264
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2265<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2266 represented using the 16-digit form shown above (which matches the IEEE754
2267 representation for double); float values must, however, be exactly
2268 representable as IEE754 single precision. Hexadecimal format is always used
2269 for long double, and there are three forms of long double. The 80-bit format
2270 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2271 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2272 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2273 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2274 currently supported target uses this format. Long doubles will only work if
2275 they match the long double format on your target. All hexadecimal formats
2276 are big-endian (sign bit at the left).</p>
2277
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2278<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2279</div>
2280
2281<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2282<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2283<a name="aggregateconstants"></a> <!-- old anchor -->
2284<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2285</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2287<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2288
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2289<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2290 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2291
2292<dl>
2293 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2294 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2295 type definitions (a comma separated list of elements, surrounded by braces
2296 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2297 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2298 Structure constants must have <a href="#t_struct">structure type</a>, and
2299 the number and types of elements must match those specified by the
2300 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2301
2302 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2303 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2304 definitions (a comma separated list of elements, surrounded by square
2305 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2306 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2307 the number and types of elements must match those specified by the
2308 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2309
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2310 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2311 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2312 definitions (a comma separated list of elements, surrounded by
2313 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2314 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2315 have <a href="#t_vector">vector type</a>, and the number and types of
2316 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2317
2318 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2319 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2320 value to zero of <em>any</em> type, including scalar and
2321 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2322 This is often used to avoid having to print large zero initializers
2323 (e.g. for large arrays) and is always exactly equivalent to using explicit
2324 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2325
2326 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2327 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2328 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2329 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2330 be interpreted as part of the instruction stream, metadata is a place to
2331 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2332</dl>
2333
2334</div>
2335
2336<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2337<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2338 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2339</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2340
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2341<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2343<p>The addresses of <a href="#globalvars">global variables</a>
2344 and <a href="#functionstructure">functions</a> are always implicitly valid
2345 (link-time) constants. These constants are explicitly referenced when
2346 the <a href="#identifiers">identifier for the global</a> is used and always
2347 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2348 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2349
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2350<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2351@X = global i32 17
2352@Y = global i32 42
2353@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2354</pre>
2355
2356</div>
2357
2358<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2359<h3>
2360 <a name="undefvalues">Undefined Values</a>
2361</h3>
2362
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2363<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2364
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2365<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2366 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2367 Undefined values may be of any type (other than '<tt>label</tt>'
2368 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2369
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2370<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2371 program is well defined no matter what value is used. This gives the
2372 compiler more freedom to optimize. Here are some examples of (potentially
2373 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2374
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2375
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2376<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2377 %A = add %X, undef
2378 %B = sub %X, undef
2379 %C = xor %X, undef
2380Safe:
2381 %A = undef
2382 %B = undef
2383 %C = undef
2384</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2385
2386<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2387 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2388
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2389<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2390 %A = or %X, undef
2391 %B = and %X, undef
2392Safe:
2393 %A = -1
2394 %B = 0
2395Unsafe:
2396 %A = undef
2397 %B = undef
2398</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2399
2400<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2401 For example, if <tt>%X</tt> has a zero bit, then the output of the
2402 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2403 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2404 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2405 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2406 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2407 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2408 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2409
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2410<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2411 %A = select undef, %X, %Y
2412 %B = select undef, 42, %Y
2413 %C = select %X, %Y, undef
2414Safe:
2415 %A = %X (or %Y)
2416 %B = 42 (or %Y)
2417 %C = %Y
2418Unsafe:
2419 %A = undef
2420 %B = undef
2421 %C = undef
2422</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2423
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2424<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2425 branch) conditions can go <em>either way</em>, but they have to come from one
2426 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2427 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2428 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2429 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2430 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2431 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2432
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2433<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2434 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2435
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2436 %B = undef
2437 %C = xor %B, %B
2438
2439 %D = undef
2440 %E = icmp lt %D, 4
2441 %F = icmp gte %D, 4
2442
2443Safe:
2444 %A = undef
2445 %B = undef
2446 %C = undef
2447 %D = undef
2448 %E = undef
2449 %F = undef
2450</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2451
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2452<p>This example points out that two '<tt>undef</tt>' operands are not
2453 necessarily the same. This can be surprising to people (and also matches C
2454 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2455 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2456 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2457 its value over its "live range". This is true because the variable doesn't
2458 actually <em>have a live range</em>. Instead, the value is logically read
2459 from arbitrary registers that happen to be around when needed, so the value
2460 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2461 need to have the same semantics or the core LLVM "replace all uses with"
2462 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2463
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2464<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2465 %A = fdiv undef, %X
2466 %B = fdiv %X, undef
2467Safe:
2468 %A = undef
2469b: unreachable
2470</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2471
2472<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2473 value</em> and <em>undefined behavior</em>. An undefined value (like
2474 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2475 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2476 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2477 defined on SNaN's. However, in the second example, we can make a more
2478 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2479 arbitrary value, we are allowed to assume that it could be zero. Since a
2480 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2481 the operation does not execute at all. This allows us to delete the divide and
2482 all code after it. Because the undefined operation "can't happen", the
2483 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2484
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2485<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2486a: store undef -> %X
2487b: store %X -> undef
2488Safe:
2489a: &lt;deleted&gt;
2490b: unreachable
2491</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2492
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2493<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2494 undefined value can be assumed to not have any effect; we can assume that the
2495 value is overwritten with bits that happen to match what was already there.
2496 However, a store <em>to</em> an undefined location could clobber arbitrary
2497 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2498
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2499</div>
2500
2501<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2502<h3>
2503 <a name="trapvalues">Trap Values</a>
2504</h3>
2505
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2506<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2507
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2508<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2509 instead of representing an unspecified bit pattern, they represent the
2510 fact that an instruction or constant expression which cannot evoke side
2511 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2512 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2513
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2514<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2515 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2516 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2517
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2518<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2519
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2520<ul>
2521<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2522 their operands.</li>
2523
2524<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2525 to their dynamic predecessor basic block.</li>
2526
2527<li>Function arguments depend on the corresponding actual argument values in
2528 the dynamic callers of their functions.</li>
2529
2530<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2531 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2532 control back to them.</li>
2533
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2534<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2535 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2536 or exception-throwing call instructions that dynamically transfer control
2537 back to them.</li>
2538
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2539<li>Non-volatile loads and stores depend on the most recent stores to all of the
2540 referenced memory addresses, following the order in the IR
2541 (including loads and stores implied by intrinsics such as
2542 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2543
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2544<!-- TODO: In the case of multiple threads, this only applies if the store
2545 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2546
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2547<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2548
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2549<li>An instruction with externally visible side effects depends on the most
2550 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2551 the order in the IR. (This includes
2552 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2553
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2554<li>An instruction <i>control-depends</i> on a
2555 <a href="#terminators">terminator instruction</a>
2556 if the terminator instruction has multiple successors and the instruction
2557 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2558 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2559
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2560<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2561 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2562 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2563 successor.</li>
2564
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2565<li>Dependence is transitive.</li>
2566
2567</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2568
2569<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames91fc0902011-10-13 23:04:49 +0000[diff] [blame]2570 to trap. If they have side effects, they evoke their side effects as if each
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2571 operand with a trap value were undef. If they have externally-visible side
2572 effects, the behavior is undefined.</p>
2573
2574<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2575
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2576<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2577entry:
2578 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2579 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2580 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2581 store i32 0, i32* %trap_yet_again ; undefined behavior
2582
2583 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2584 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2585
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2586 store volatile i32 %trap, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2587
2588 %narrowaddr = bitcast i32* @g to i16*
2589 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2590 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2591 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2592
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2593 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2594 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2595
2596true:
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2597 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2598 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2599 br label %end
2600
2601end:
2602 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2603 ; Both edges into this PHI are
2604 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2605 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2606
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2607 store volatile i32 0, i32* @g ; This would depend on the store in %true
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2608 ; if %cmp is true, or the store in %entry
2609 ; otherwise, so this is undefined behavior.
2610
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2611 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2612 ; The same branch again, but this time the
2613 ; true block doesn't have side effects.
2614
2615second_true:
2616 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2617 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2618
2619second_end:
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2620 store volatile i32 0, i32* @g ; This time, the instruction always depends
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2621 ; on the store in %end. Also, it is
2622 ; control-equivalent to %end, so this is
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2623 ; well-defined (again, ignoring earlier
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2624 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2625</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2626
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2627</div>
2628
2629<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2630<h3>
2631 <a name="blockaddress">Addresses of Basic Blocks</a>
2632</h3>
2633
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2634<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2635
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2636<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2637
2638<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2639 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2640 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2641
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2642<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2643 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2644 comparisons against null. Pointer equality tests between labels addresses
2645 results in undefined behavior &mdash; though, again, comparison against null
2646 is ok, and no label is equal to the null pointer. This may be passed around
2647 as an opaque pointer sized value as long as the bits are not inspected. This
2648 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2649 long as the original value is reconstituted before the <tt>indirectbr</tt>
2650 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2651
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2652<p>Finally, some targets may provide defined semantics when using the value as
2653 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2654
2655</div>
2656
2657
2658<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2659<h3>
2660 <a name="constantexprs">Constant Expressions</a>
2661</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2662
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2663<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2664
2665<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2666 to be used as constants. Constant expressions may be of
2667 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2668 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2669 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2670
2671<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2672 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2673 <dd>Truncate a constant to another type. The bit size of CST must be larger
2674 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2675
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2676 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2677 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2678 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2679
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2680 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2681 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2682 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2683
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2684 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2685 <dd>Truncate a floating point constant to another floating point type. The
2686 size of CST must be larger than the size of TYPE. Both types must be
2687 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2688
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2689 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2690 <dd>Floating point extend a constant to another type. The size of CST must be
2691 smaller or equal to the size of TYPE. Both types must be floating
2692 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2693
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2694 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2695 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2696 constant. TYPE must be a scalar or vector integer type. CST must be of
2697 scalar or vector floating point type. Both CST and TYPE must be scalars,
2698 or vectors of the same number of elements. If the value won't fit in the
2699 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2700
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2701 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2702 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2703 constant. TYPE must be a scalar or vector integer type. CST must be of
2704 scalar or vector floating point type. Both CST and TYPE must be scalars,
2705 or vectors of the same number of elements. If the value won't fit in the
2706 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2707
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2708 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2709 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2710 constant. TYPE must be a scalar or vector floating point type. CST must be
2711 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2712 vectors of the same number of elements. If the value won't fit in the
2713 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2714
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2715 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2716 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2717 constant. TYPE must be a scalar or vector floating point type. CST must be
2718 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2719 vectors of the same number of elements. If the value won't fit in the
2720 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2721
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2722 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2723 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2724 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2725 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2726 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2727
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2729 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2730 type. CST must be of integer type. The CST value is zero extended,
2731 truncated, or unchanged to make it fit in a pointer size. This one is
2732 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2733
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2734 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2735 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2736 are the same as those for the <a href="#i_bitcast">bitcast
2737 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2738
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2740 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2741 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2742 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2743 instruction, the index list may have zero or more indexes, which are
2744 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2745
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2746 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2747 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2748
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2750 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2751
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2753 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2754
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2756 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2757 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2758
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2761 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2762
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2764 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2765 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2766
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2767 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2768 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2769 constants. The index list is interpreted in a similar manner as indices in
2770 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2771 index value must be specified.</dd>
2772
2773 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2774 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2775 constants. The index list is interpreted in a similar manner as indices in
2776 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2777 index value must be specified.</dd>
2778
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2779 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2780 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2781 be any of the <a href="#binaryops">binary</a>
2782 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2783 on operands are the same as those for the corresponding instruction
2784 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2785</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2786
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2787</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2788
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2789</div>
2790
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2791<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2792<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2793<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2794<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2795<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2796<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2797<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2798</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2799
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2800<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2801
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2802<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2803 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2804 a special value. This value represents the inline assembler as a string
2805 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2806 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2807 expression has side effects, and a flag indicating whether the function
2808 containing the asm needs to align its stack conservatively. An example
2809 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2810
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2811<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2812i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2813</pre>
2814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2815<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2816 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2817 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2818
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2819<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2820%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2821</pre>
2822
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2823<p>Inline asms with side effects not visible in the constraint list must be
2824 marked as having side effects. This is done through the use of the
2825 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2826
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2827<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2828call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2829</pre>
2830
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2831<p>In some cases inline asms will contain code that will not work unless the
2832 stack is aligned in some way, such as calls or SSE instructions on x86,
2833 yet will not contain code that does that alignment within the asm.
2834 The compiler should make conservative assumptions about what the asm might
2835 contain and should generate its usual stack alignment code in the prologue
2836 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2837
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2838<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2839call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2840</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2841
2842<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2843 first.</p>
2844
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2845<!--
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2846<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2847 documented here. Constraints on what can be done (e.g. duplication, moving,
2848 etc need to be documented). This is probably best done by reference to
2849 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2850 -->
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2851
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2852<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2853<h4>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2854 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2855</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2856
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2857<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2858
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2859<p>The call instructions that wrap inline asm nodes may have a
2860 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2861 integers. If present, the code generator will use the integer as the
2862 location cookie value when report errors through the <tt>LLVMContext</tt>
2863 error reporting mechanisms. This allows a front-end to correlate backend
2864 errors that occur with inline asm back to the source code that produced it.
2865 For example:</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2866
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2867<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2868call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2869...
2870!42 = !{ i32 1234567 }
2871</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2872
2873<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame^]2874 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2875 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2876
2877</div>
2878
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2879</div>
2880
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2881<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2882<h3>
2883 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2884</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2885
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2886<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2887
2888<p>LLVM IR allows metadata to be attached to instructions in the program that
2889 can convey extra information about the code to the optimizers and code
2890 generator. One example application of metadata is source-level debug
2891 information. There are two metadata primitives: strings and nodes. All
2892 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2893 preceding exclamation point ('<tt>!</tt>').</p>
2894
2895<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2896 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2897 "<tt>xx</tt>" is the two digit hex code. For example:
2898 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2899
2900<p>Metadata nodes are represented with notation similar to structure constants
2901 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2902 exclamation point). Metadata nodes can have any values as their operand. For
2903 example:</p>
2904
2905<div class="doc_code">
2906<pre>
2907!{ metadata !"test\00", i32 10}
2908</pre>
2909</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2910
2911<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2912 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2913 example:</p>
2914
2915<div class="doc_code">
2916<pre>
2917!foo = metadata !{!4, !3}
2918</pre>
2919</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2920
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2921<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2922 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2923
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2924<div class="doc_code">
2925<pre>
2926call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2927</pre>
2928</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2929
2930<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2931 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2932 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2933
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2934<div class="doc_code">
2935<pre>
2936%indvar.next = add i64 %indvar, 1, !dbg !21
2937</pre>
2938</div>
2939
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2940<p>More information about specific metadata nodes recognized by the optimizers
2941 and code generator is found below.</p>
2942
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2943<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2944<h4>
2945 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2946</h4>
2947
2948<div>
2949
2950<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2951 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2952 a type system of a higher level language. This can be used to implement
2953 typical C/C++ TBAA, but it can also be used to implement custom alias
2954 analysis behavior for other languages.</p>
2955
2956<p>The current metadata format is very simple. TBAA metadata nodes have up to
2957 three fields, e.g.:</p>
2958
2959<div class="doc_code">
2960<pre>
2961!0 = metadata !{ metadata !"an example type tree" }
2962!1 = metadata !{ metadata !"int", metadata !0 }
2963!2 = metadata !{ metadata !"float", metadata !0 }
2964!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2965</pre>
2966</div>
2967
2968<p>The first field is an identity field. It can be any value, usually
2969 a metadata string, which uniquely identifies the type. The most important
2970 name in the tree is the name of the root node. Two trees with
2971 different root node names are entirely disjoint, even if they
2972 have leaves with common names.</p>
2973
2974<p>The second field identifies the type's parent node in the tree, or
2975 is null or omitted for a root node. A type is considered to alias
2976 all of its descendants and all of its ancestors in the tree. Also,
2977 a type is considered to alias all types in other trees, so that
2978 bitcode produced from multiple front-ends is handled conservatively.</p>
2979
2980<p>If the third field is present, it's an integer which if equal to 1
2981 indicates that the type is "constant" (meaning
2982 <tt>pointsToConstantMemory</tt> should return true; see
2983 <a href="AliasAnalysis.html#OtherItfs">other useful
2984 <tt>AliasAnalysis</tt> methods</a>).</p>
2985
2986</div>
2987
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2988<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]2989<h4>
2990 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2991</h4>
2992
2993<div>
2994
2995<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
2996 point type. It expresses the maximum relative error of the result of
2997 that instruction, in ULPs. ULP is defined as follows:</p>
2998
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]2999<blockquote>
3000
3001<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3002 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3003 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3004 distance between the two non-equal finite floating-point numbers nearest
3005 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3006
3007</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3008
3009<p>The maximum relative error may be any rational number. The metadata node
3010 shall consist of a pair of unsigned integers respectively representing
3011 the numerator and denominator. For example, 2.5 ULP:</p>
3012
3013<div class="doc_code">
3014<pre>
3015!0 = metadata !{ i32 5, i32 2 }
3016</pre>
3017</div>
3018
3019</div>
3020
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3021</div>
3022
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3023</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3024
3025<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3026<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3027 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3028</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3029<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3030<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3031<p>LLVM has a number of "magic" global variables that contain data that affect
3032code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3033of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3034section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3035by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3036
3037<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3038<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3039<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3040</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3041
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3042<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3043
3044<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3045href="#linkage_appending">appending linkage</a>. This array contains a list of
3046pointers to global variables and functions which may optionally have a pointer
3047cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3048
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3049<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3050<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3051@X = global i8 4
3052@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3053
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3054@llvm.used = appending global [2 x i8*] [
3055 i8* @X,
3056 i8* bitcast (i32* @Y to i8*)
3057], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3058</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3059</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3060
3061<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3062 compiler, assembler, and linker are required to treat the symbol as if there
3063 is a reference to the global that it cannot see. For example, if a variable
3064 has internal linkage and no references other than that from
3065 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3066 represent references from inline asms and other things the compiler cannot
3067 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3068
3069<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3070 object file to prevent the assembler and linker from molesting the
3071 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3072
3073</div>
3074
3075<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3076<h3>
3077 <a name="intg_compiler_used">
3078 The '<tt>llvm.compiler.used</tt>' Global Variable
3079 </a>
3080</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3081
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3082<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3083
3084<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3085 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3086 touching the symbol. On targets that support it, this allows an intelligent
3087 linker to optimize references to the symbol without being impeded as it would
3088 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3089
3090<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3091 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3092
3093</div>
3094
3095<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3096<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3097<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3098</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3099
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3100<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3101
3102<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3103<pre>
3104%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3105@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3106</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3107</div>
3108
3109<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3110 functions and associated priorities. The functions referenced by this array
3111 will be called in ascending order of priority (i.e. lowest first) when the
3112 module is loaded. The order of functions with the same priority is not
3113 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3114
3115</div>
3116
3117<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3118<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3119<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3120</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3121
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3122<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3123
3124<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3125<pre>
3126%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3127@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3128</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3129</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3130
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3131<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3132 and associated priorities. The functions referenced by this array will be
3133 called in descending order of priority (i.e. highest first) when the module
3134 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3135
3136</div>
3137
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3138</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3139
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3140<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3141<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3142<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3143
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3144<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3145
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3146<p>The LLVM instruction set consists of several different classifications of
3147 instructions: <a href="#terminators">terminator
3148 instructions</a>, <a href="#binaryops">binary instructions</a>,
3149 <a href="#bitwiseops">bitwise binary instructions</a>,
3150 <a href="#memoryops">memory instructions</a>, and
3151 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3152
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3153<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3154<h3>
3155 <a name="terminators">Terminator Instructions</a>
3156</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3157
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3158<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3159
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3160<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3161 in a program ends with a "Terminator" instruction, which indicates which
3162 block should be executed after the current block is finished. These
3163 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3164 control flow, not values (the one exception being the
3165 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3166
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3167<p>The terminator instructions are:
3168 '<a href="#i_ret"><tt>ret</tt></a>',
3169 '<a href="#i_br"><tt>br</tt></a>',
3170 '<a href="#i_switch"><tt>switch</tt></a>',
3171 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3172 '<a href="#i_invoke"><tt>invoke</tt></a>',
3173 '<a href="#i_unwind"><tt>unwind</tt></a>',
3174 '<a href="#i_resume"><tt>resume</tt></a>', and
3175 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3176
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3177<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3178<h4>
3179 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3180</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3181
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3182<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3184<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3185<pre>
3186 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3187 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3188</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3189
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3190<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3191<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3192 a value) from a function back to the caller.</p>
3193
3194<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3195 value and then causes control flow, and one that just causes control flow to
3196 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3197
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3198<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3199<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3200 return value. The type of the return value must be a
3201 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3202
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3203<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3204 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3205 value or a return value with a type that does not match its type, or if it
3206 has a void return type and contains a '<tt>ret</tt>' instruction with a
3207 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3209<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3210<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3211 the calling function's context. If the caller is a
3212 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3213 instruction after the call. If the caller was an
3214 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3215 the beginning of the "normal" destination block. If the instruction returns
3216 a value, that value shall set the call or invoke instruction's return
3217 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3218
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3219<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3220<pre>
3221 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3222 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3223 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3224</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3225
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3226</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3227<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3228<h4>
3229 <a name="i_br">'<tt>br</tt>' Instruction</a>
3230</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3231
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3232<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3233
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3234<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3236 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3237 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3238</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3239
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3240<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3242 different basic block in the current function. There are two forms of this
3243 instruction, corresponding to a conditional branch and an unconditional
3244 branch.</p>
3245
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3246<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3247<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3248 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3249 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3250 target.</p>
3251
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3252<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3253<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3254 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3255 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3256 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3257
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3259<pre>
3260Test:
3261 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3262 br i1 %cond, label %IfEqual, label %IfUnequal
3263IfEqual:
3264 <a href="#i_ret">ret</a> i32 1
3265IfUnequal:
3266 <a href="#i_ret">ret</a> i32 0
3267</pre>
3268
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3269</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3270
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3271<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3272<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3273 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3274</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3275
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3276<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3277
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3278<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3279<pre>
3280 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3281</pre>
3282
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3283<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3284<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3285 several different places. It is a generalization of the '<tt>br</tt>'
3286 instruction, allowing a branch to occur to one of many possible
3287 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3288
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3289<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3290<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3291 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3292 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3293 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3294
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3295<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3296<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3297 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3298 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3299 transferred to the corresponding destination; otherwise, control flow is
3300 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3301
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3302<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3303<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3304 <tt>switch</tt> instruction, this instruction may be code generated in
3305 different ways. For example, it could be generated as a series of chained
3306 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3307
3308<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3309<pre>
3310 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3311 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3312 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3313
3314 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3315 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3316
3317 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3318 switch i32 %val, label %otherwise [ i32 0, label %onzero
3319 i32 1, label %onone
3320 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3321</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3322
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3323</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3324
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3325
3326<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3327<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3328 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3329</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3330
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3331<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3332
3333<h5>Syntax:</h5>
3334<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3335 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3336</pre>
3337
3338<h5>Overview:</h5>
3339
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3340<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3341 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3342 "<tt>address</tt>". Address must be derived from a <a
3343 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3344
3345<h5>Arguments:</h5>
3346
3347<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3348 rest of the arguments indicate the full set of possible destinations that the
3349 address may point to. Blocks are allowed to occur multiple times in the
3350 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3351
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3352<p>This destination list is required so that dataflow analysis has an accurate
3353 understanding of the CFG.</p>
3354
3355<h5>Semantics:</h5>
3356
3357<p>Control transfers to the block specified in the address argument. All
3358 possible destination blocks must be listed in the label list, otherwise this
3359 instruction has undefined behavior. This implies that jumps to labels
3360 defined in other functions have undefined behavior as well.</p>
3361
3362<h5>Implementation:</h5>
3363
3364<p>This is typically implemented with a jump through a register.</p>
3365
3366<h5>Example:</h5>
3367<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3368 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3369</pre>
3370
3371</div>
3372
3373
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3374<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3375<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3376 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3377</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3378
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3379<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3380
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3381<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3382<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3383 &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 Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]3384 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3385</pre>
3386
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3387<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3388<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3389 function, with the possibility of control flow transfer to either the
3390 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3391 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3392 control flow will return to the "normal" label. If the callee (or any
3393 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3394 instruction, control is interrupted and continued at the dynamically nearest
3395 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3396
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3397<p>The '<tt>exception</tt>' label is a
3398 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3399 exception. As such, '<tt>exception</tt>' label is required to have the
3400 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3401 the information about about the behavior of the program after unwinding
3402 happens, as its first non-PHI instruction. The restrictions on the
3403 "<tt>landingpad</tt>" instruction's tightly couples it to the
3404 "<tt>invoke</tt>" instruction, so that the important information contained
3405 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3406 code motion.</p>
3407
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3408<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3409<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3410
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3411<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3412 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3413 convention</a> the call should use. If none is specified, the call
3414 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3415
3416 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3418 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3419
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3420 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3421 function value being invoked. In most cases, this is a direct function
3422 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3423 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3424
3425 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3426 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3427
3428 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3429 signature argument types and parameter attributes. All arguments must be
3430 of <a href="#t_firstclass">first class</a> type. If the function
3431 signature indicates the function accepts a variable number of arguments,
3432 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3433
3434 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3435 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3436
3437 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3438 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3439
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3440 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3441 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3442 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3443</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3445<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3446<p>This instruction is designed to operate as a standard
3447 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3448 primary difference is that it establishes an association with a label, which
3449 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3450
3451<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3453 exception. Additionally, this is important for implementation of
3454 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3455
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3456<p>For the purposes of the SSA form, the definition of the value returned by the
3457 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3458 block to the "normal" label. If the callee unwinds then no return value is
3459 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3460
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3461<p>Note that the code generator does not yet completely support unwind, and
3462that the invoke/unwind semantics are likely to change in future versions.</p>
3463
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3464<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3465<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3466 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3467 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3468 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3469 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3470</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3471
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3472</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3473
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3474<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3475
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3476<h4>
3477 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3478</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3479
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3480<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3481
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3482<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3483<pre>
3484 unwind
3485</pre>
3486
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3487<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3488<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489 at the first callee in the dynamic call stack which used
3490 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3491 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3492
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3493<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3494<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495 immediately halt. The dynamic call stack is then searched for the
3496 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3497 Once found, execution continues at the "exceptional" destination block
3498 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3499 instruction in the dynamic call chain, undefined behavior results.</p>
3500
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3501<p>Note that the code generator does not yet completely support unwind, and
3502that the invoke/unwind semantics are likely to change in future versions.</p>
3503
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3504</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3505
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3506 <!-- _______________________________________________________________________ -->
3507
3508<h4>
3509 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3510</h4>
3511
3512<div>
3513
3514<h5>Syntax:</h5>
3515<pre>
3516 resume &lt;type&gt; &lt;value&gt;
3517</pre>
3518
3519<h5>Overview:</h5>
3520<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3521 successors.</p>
3522
3523<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3524<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3525 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3526 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3527
3528<h5>Semantics:</h5>
3529<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3530 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3531 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3532
3533<h5>Example:</h5>
3534<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3535 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3536</pre>
3537
3538</div>
3539
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3540<!-- _______________________________________________________________________ -->
3541
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3542<h4>
3543 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3544</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3545
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3546<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3547
3548<h5>Syntax:</h5>
3549<pre>
3550 unreachable
3551</pre>
3552
3553<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3554<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3555 instruction is used to inform the optimizer that a particular portion of the
3556 code is not reachable. This can be used to indicate that the code after a
3557 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3558
3559<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3560<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3561
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3562</div>
3563
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3564</div>
3565
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3566<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3567<h3>
3568 <a name="binaryops">Binary Operations</a>
3569</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3570
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3571<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3572
3573<p>Binary operators are used to do most of the computation in a program. They
3574 require two operands of the same type, execute an operation on them, and
3575 produce a single value. The operands might represent multiple data, as is
3576 the case with the <a href="#t_vector">vector</a> data type. The result value
3577 has the same type as its operands.</p>
3578
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3579<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3580
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3581<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3582<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3583 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3584</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3585
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3586<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3587
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3588<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3589<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3590 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3591 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3592 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3593 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3594</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3595
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3596<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3597<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3598
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3599<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3600<p>The two arguments to the '<tt>add</tt>' instruction must
3601 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3602 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3604<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3605<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3606
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3607<p>If the sum has unsigned overflow, the result returned is the mathematical
3608 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3609
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3610<p>Because LLVM integers use a two's complement representation, this instruction
3611 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3612
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3613<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3614 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3615 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3616 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3617 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3618
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3619<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3620<pre>
3621 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3622</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3623
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3624</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3626<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3627<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3628 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3629</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3630
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3631<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3632
3633<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3634<pre>
3635 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3636</pre>
3637
3638<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3639<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3640
3641<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3642<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3643 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3644 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3645
3646<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3647<p>The value produced is the floating point sum of the two operands.</p>
3648
3649<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3650<pre>
3651 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3652</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3653
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3654</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3655
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3656<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3657<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3658 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3659</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3660
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3661<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3662
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3663<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3664<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3665 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3666 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3667 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3668 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3669</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3670
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3671<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3672<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3673 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3674
3675<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3676 '<tt>neg</tt>' instruction present in most other intermediate
3677 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3678
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3679<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3680<p>The two arguments to the '<tt>sub</tt>' instruction must
3681 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3682 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3683
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3684<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3685<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3686
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3687<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3688 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3689 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3690
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3691<p>Because LLVM integers use a two's complement representation, this instruction
3692 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3693
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3694<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3695 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3696 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3697 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3698 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3699
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3700<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3701<pre>
3702 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3703 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3704</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3705
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3706</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3707
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3708<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3709<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3710 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3711</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3712
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3713<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3714
3715<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3716<pre>
3717 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3718</pre>
3719
3720<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3721<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3722 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3723
3724<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3725 '<tt>fneg</tt>' instruction present in most other intermediate
3726 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3727
3728<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3729<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3730 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3731 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3732
3733<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3734<p>The value produced is the floating point difference of the two operands.</p>
3735
3736<h5>Example:</h5>
3737<pre>
3738 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3739 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3740</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3742</div>
3743
3744<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3745<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3746 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3747</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3748
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3749<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3750
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3751<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3752<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3753 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3754 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3755 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3756 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3757</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3758
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3759<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3760<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3761
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3762<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3763<p>The two arguments to the '<tt>mul</tt>' instruction must
3764 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3765 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3766
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3767<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3768<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3769
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3770<p>If the result of the multiplication has unsigned overflow, the result
3771 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3772 width of the result.</p>
3773
3774<p>Because LLVM integers use a two's complement representation, and the result
3775 is the same width as the operands, this instruction returns the correct
3776 result for both signed and unsigned integers. If a full product
3777 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3778 be sign-extended or zero-extended as appropriate to the width of the full
3779 product.</p>
3780
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3781<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3782 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3783 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3784 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3785 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3786
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3787<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3788<pre>
3789 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3790</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3791
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3792</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3793
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3794<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3795<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3796 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3797</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3798
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3799<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3800
3801<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3802<pre>
3803 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3804</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3805
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3806<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3808
3809<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3810<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3811 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3812 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3813
3814<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3815<p>The value produced is the floating point product of the two operands.</p>
3816
3817<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3818<pre>
3819 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3820</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3821
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3822</div>
3823
3824<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3825<h4>
3826 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3827</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3829<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3830
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3831<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3832<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3833 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3834 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3835</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3836
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3837<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3838<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3839
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3840<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3841<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3842 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3843 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3844
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3845<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3846<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3847
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3848<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3849 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3850
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3851<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3852
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3853<p>If the <tt>exact</tt> keyword is present, the result value of the
3854 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3855 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3856
3857
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3858<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3859<pre>
3860 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3861</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3862
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3863</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3864
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3865<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3866<h4>
3867 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3868</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3869
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3870<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3871
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3872<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3873<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3874 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3875 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3876</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3877
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3878<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3879<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3880
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3881<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3882<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3884 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3885
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3886<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3887<p>The value produced is the signed integer quotient of the two operands rounded
3888 towards zero.</p>
3889
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3890<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3891 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3892
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3893<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3894 undefined behavior; this is a rare case, but can occur, for example, by doing
3895 a 32-bit division of -2147483648 by -1.</p>
3896
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3897<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3898 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohmane501ff72010-07-11 00:08:34 +0000[diff] [blame]3899 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3900
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3901<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3902<pre>
3903 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3904</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3906</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3908<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3909<h4>
3910 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3911</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3912
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3913<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3914
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3915<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3916<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3917 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3918</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3919
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3920<h5>Overview:</h5>
3921<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3922
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3923<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3924<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3925 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3926 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3927
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3928<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3929<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3930
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3931<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3932<pre>
3933 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3934</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3935
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3936</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3937
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3938<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3939<h4>
3940 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3941</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3942
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3943<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3945<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946<pre>
3947 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3948</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3950<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3952 division of its two arguments.</p>
3953
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3954<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3955<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3956 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3957 values. Both arguments must have identical types.</p>
3958
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3959<h5>Semantics:</h5>
3960<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3961 This instruction always performs an unsigned division to get the
3962 remainder.</p>
3963
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3964<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3965 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3966
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3967<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3968
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3969<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3970<pre>
3971 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3972</pre>
3973
3974</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3975
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3976<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3977<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3978 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3979</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3980
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3981<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3982
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3983<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3984<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3985 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3986</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3987
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3988<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3989<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3990 division of its two operands. This instruction can also take
3991 <a href="#t_vector">vector</a> versions of the values in which case the
3992 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3993
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3994<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3995<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3996 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3997 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3998
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3999<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4000<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]4001 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4002 <i>modulo</i> operator (where the result is either zero or has the same sign
4003 as the divisor, <tt>op2</tt>) of a value.
4004 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4005 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4006 Math Forum</a>. For a table of how this is implemented in various languages,
4007 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4008 Wikipedia: modulo operation</a>.</p>
4009
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4010<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4011 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4012
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4013<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4014 Overflow also leads to undefined behavior; this is a rare case, but can
4015 occur, for example, by taking the remainder of a 32-bit division of
4016 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4017 lets srem be implemented using instructions that return both the result of
4018 the division and the remainder.)</p>
4019
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4020<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021<pre>
4022 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4023</pre>
4024
4025</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4026
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4027<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4028<h4>
4029 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4030</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4031
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4032<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4033
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4034<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4035<pre>
4036 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4037</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4038
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4039<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4041 its two operands.</p>
4042
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4043<h5>Arguments:</h5>
4044<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4045 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4046 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4047
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4048<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4049<p>This instruction returns the <i>remainder</i> of a division. The remainder
4050 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4051
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4052<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4053<pre>
4054 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4055</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4056
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4057</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4058
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4059</div>
4060
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4061<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4062<h3>
4063 <a name="bitwiseops">Bitwise Binary Operations</a>
4064</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4065
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4066<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4067
4068<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4069 program. They are generally very efficient instructions and can commonly be
4070 strength reduced from other instructions. They require two operands of the
4071 same type, execute an operation on them, and produce a single value. The
4072 resulting value is the same type as its operands.</p>
4073
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4074<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4075<h4>
4076 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4077</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4078
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4079<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4080
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4081<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4083 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4084 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4085 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4086 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4087</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4088
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4089<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4090<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4091 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4092
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4093<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4094<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4095 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4096 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4097
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4098<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4099<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4100 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4101 is (statically or dynamically) negative or equal to or larger than the number
4102 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4103 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4104 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4105
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4106<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4107 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattnerf10dfdc2011-02-09 16:44:44 +0000[diff] [blame]4108 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4109 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4110 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4111 they would if the shift were expressed as a mul instruction with the same
4112 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4113
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4114<h5>Example:</h5>
4115<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4116 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4117 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4118 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4119 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4120 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4121</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4122
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4123</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4125<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4126<h4>
4127 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4128</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4130<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4132<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4133<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4134 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4135 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4136</pre>
4137
4138<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4139<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4140 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4141
4142<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4143<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4144 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4145 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4146
4147<h5>Semantics:</h5>
4148<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4149 significant bits of the result will be filled with zero bits after the shift.
4150 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4151 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4152 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4153 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4154
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4155<p>If the <tt>exact</tt> keyword is present, the result value of the
4156 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4157 shifted out are non-zero.</p>
4158
4159
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4160<h5>Example:</h5>
4161<pre>
4162 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4163 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4164 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4165 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4166 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4167 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4168</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4169
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4170</div>
4171
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4172<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4173<h4>
4174 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4175</h4>
4176
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4177<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4178
4179<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4181 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4182 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4183</pre>
4184
4185<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4186<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4187 operand shifted to the right a specified number of bits with sign
4188 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4189
4190<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4191<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4192 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4193 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4194
4195<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4196<p>This instruction always performs an arithmetic shift right operation, The
4197 most significant bits of the result will be filled with the sign bit
4198 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4199 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4200 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4201 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4202
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4203<p>If the <tt>exact</tt> keyword is present, the result value of the
4204 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4205 shifted out are non-zero.</p>
4206
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4207<h5>Example:</h5>
4208<pre>
4209 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4210 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4211 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4212 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4213 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4214 &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 Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4215</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4216
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4217</div>
4218
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4219<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4220<h4>
4221 <a name="i_and">'<tt>and</tt>' Instruction</a>
4222</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4223
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4224<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4226<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4227<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4228 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4229</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4230
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4231<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4232<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4233 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4235<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4236<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4237 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4238 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4239
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4240<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4241<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4242
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4243<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4244 <tbody>
4245 <tr>
4246 <td>In0</td>
4247 <td>In1</td>
4248 <td>Out</td>
4249 </tr>
4250 <tr>
4251 <td>0</td>
4252 <td>0</td>
4253 <td>0</td>
4254 </tr>
4255 <tr>
4256 <td>0</td>
4257 <td>1</td>
4258 <td>0</td>
4259 </tr>
4260 <tr>
4261 <td>1</td>
4262 <td>0</td>
4263 <td>0</td>
4264 </tr>
4265 <tr>
4266 <td>1</td>
4267 <td>1</td>
4268 <td>1</td>
4269 </tr>
4270 </tbody>
4271</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4272
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4273<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4274<pre>
4275 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4276 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4277 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4278</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4279</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4280<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4281<h4>
4282 <a name="i_or">'<tt>or</tt>' Instruction</a>
4283</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4284
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4285<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4286
4287<h5>Syntax:</h5>
4288<pre>
4289 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4290</pre>
4291
4292<h5>Overview:</h5>
4293<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4294 two operands.</p>
4295
4296<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4297<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4298 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4299 values. Both arguments must have identical types.</p>
4300
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4301<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4302<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4303
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4304<table border="1" cellspacing="0" cellpadding="4">
4305 <tbody>
4306 <tr>
4307 <td>In0</td>
4308 <td>In1</td>
4309 <td>Out</td>
4310 </tr>
4311 <tr>
4312 <td>0</td>
4313 <td>0</td>
4314 <td>0</td>
4315 </tr>
4316 <tr>
4317 <td>0</td>
4318 <td>1</td>
4319 <td>1</td>
4320 </tr>
4321 <tr>
4322 <td>1</td>
4323 <td>0</td>
4324 <td>1</td>
4325 </tr>
4326 <tr>
4327 <td>1</td>
4328 <td>1</td>
4329 <td>1</td>
4330 </tr>
4331 </tbody>
4332</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4334<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335<pre>
4336 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4337 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4338 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4339</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4341</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4342
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4343<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4344<h4>
4345 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4346</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4347
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4348<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4350<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351<pre>
4352 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4353</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4354
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4355<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4356<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4357 its two operands. The <tt>xor</tt> is used to implement the "one's
4358 complement" operation, which is the "~" operator in C.</p>
4359
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4360<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4361<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4362 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4363 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4364
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4365<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4366<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4367
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4368<table border="1" cellspacing="0" cellpadding="4">
4369 <tbody>
4370 <tr>
4371 <td>In0</td>
4372 <td>In1</td>
4373 <td>Out</td>
4374 </tr>
4375 <tr>
4376 <td>0</td>
4377 <td>0</td>
4378 <td>0</td>
4379 </tr>
4380 <tr>
4381 <td>0</td>
4382 <td>1</td>
4383 <td>1</td>
4384 </tr>
4385 <tr>
4386 <td>1</td>
4387 <td>0</td>
4388 <td>1</td>
4389 </tr>
4390 <tr>
4391 <td>1</td>
4392 <td>1</td>
4393 <td>0</td>
4394 </tr>
4395 </tbody>
4396</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4397
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4398<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4399<pre>
4400 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4401 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4402 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4403 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4404</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4405
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4406</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4407
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4408</div>
4409
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4410<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4411<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4412 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4413</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4414
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4415<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4416
4417<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4418 target-independent manner. These instructions cover the element-access and
4419 vector-specific operations needed to process vectors effectively. While LLVM
4420 does directly support these vector operations, many sophisticated algorithms
4421 will want to use target-specific intrinsics to take full advantage of a
4422 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4423
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4424<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4425<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4426 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4427</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4428
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4429<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4430
4431<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4432<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4433 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4434</pre>
4435
4436<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4437<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4438 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4439
4440
4441<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4442<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4443 of <a href="#t_vector">vector</a> type. The second operand is an index
4444 indicating the position from which to extract the element. The index may be
4445 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4446
4447<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4448<p>The result is a scalar of the same type as the element type of
4449 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4450 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4451 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4452
4453<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4454<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4455 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4456</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4457
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4458</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4459
4460<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4461<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4462 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4463</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4464
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4465<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4466
4467<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4468<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4469 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4470</pre>
4471
4472<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4473<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4474 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4475
4476<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4477<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4478 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4479 whose type must equal the element type of the first operand. The third
4480 operand is an index indicating the position at which to insert the value.
4481 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4482
4483<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4484<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4485 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4486 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4487 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4488
4489<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4490<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4491 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4492</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4493
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4494</div>
4495
4496<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4497<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4498 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4499</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4500
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4501<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4502
4503<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4504<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4505 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4506</pre>
4507
4508<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4509<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4510 from two input vectors, returning a vector with the same element type as the
4511 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4512
4513<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4514<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4515 with types that match each other. The third argument is a shuffle mask whose
4516 element type is always 'i32'. The result of the instruction is a vector
4517 whose length is the same as the shuffle mask and whose element type is the
4518 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4519
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4520<p>The shuffle mask operand is required to be a constant vector with either
4521 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4522
4523<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4524<p>The elements of the two input vectors are numbered from left to right across
4525 both of the vectors. The shuffle mask operand specifies, for each element of
4526 the result vector, which element of the two input vectors the result element
4527 gets. The element selector may be undef (meaning "don't care") and the
4528 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4529
4530<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4531<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4532 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4533 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4534 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4535 &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.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4536 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4537 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4538 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4539 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4540</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4541
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4542</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4543
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4544</div>
4545
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4546<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4547<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4548 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4549</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4550
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4551<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4552
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4553<p>LLVM supports several instructions for working with
4554 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4555
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4556<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4557<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4558 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4559</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4560
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4561<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4562
4563<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4564<pre>
4565 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4566</pre>
4567
4568<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4569<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4570 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4571
4572<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4573<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4574 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4575 <a href="#t_array">array</a> type. The operands are constant indices to
4576 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4577 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4578 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4579 <ul>
4580 <li>Since the value being indexed is not a pointer, the first index is
4581 omitted and assumed to be zero.</li>
4582 <li>At least one index must be specified.</li>
4583 <li>Not only struct indices but also array indices must be in
4584 bounds.</li>
4585 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4586
4587<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4588<p>The result is the value at the position in the aggregate specified by the
4589 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4590
4591<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4592<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4593 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4594</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4595
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4596</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4597
4598<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4599<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4600 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4601</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4602
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4603<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4604
4605<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4606<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4607 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt;{, &lt;idx&gt;}* <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4608</pre>
4609
4610<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4611<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4612 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4613
4614<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4615<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4616 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4617 <a href="#t_array">array</a> type. The second operand is a first-class
4618 value to insert. The following operands are constant indices indicating
4619 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4620 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4621 value to insert must have the same type as the value identified by the
4622 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4623
4624<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4625<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4626 that of <tt>val</tt> except that the value at the position specified by the
4627 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4628
4629<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4630<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4631 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4632 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4633 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4634</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4635
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4636</div>
4637
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4638</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4639
4640<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4641<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4642 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4643</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4644
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4645<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4646
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4647<p>A key design point of an SSA-based representation is how it represents
4648 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4649 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4650 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4651
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4652<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4653<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4654 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4655</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4656
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4657<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4658
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4659<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4660<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4661 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4662</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4663
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4664<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4665<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4666 currently executing function, to be automatically released when this function
4667 returns to its caller. The object is always allocated in the generic address
4668 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4670<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671<p>The '<tt>alloca</tt>' instruction
4672 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4673 runtime stack, returning a pointer of the appropriate type to the program.
4674 If "NumElements" is specified, it is the number of elements allocated,
4675 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4676 specified, the value result of the allocation is guaranteed to be aligned to
4677 at least that boundary. If not specified, or if zero, the target can choose
4678 to align the allocation on any convenient boundary compatible with the
4679 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4680
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4681<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4682
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4683<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4684<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4685 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4686 memory is automatically released when the function returns. The
4687 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4688 variables that must have an address available. When the function returns
4689 (either with the <tt><a href="#i_ret">ret</a></tt>
4690 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4691 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4692
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4693<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4694<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4695 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4696 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4697 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4698 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4699</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4700
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4701</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4702
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4703<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4704<h4>
4705 <a name="i_load">'<tt>load</tt>' Instruction</a>
4706</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4707
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4708<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4709
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4710<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4711<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4712 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4713 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4714 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4715</pre>
4716
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4717<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4718<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4719
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4720<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4722 from which to load. The pointer must point to
4723 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4724 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4725 number or order of execution of this <tt>load</tt> with other <a
4726 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4727
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4728<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4729 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4730 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4731 not valid on <code>load</code> instructions. Atomic loads produce <a
4732 href="#memorymodel">defined</a> results when they may see multiple atomic
4733 stores. The type of the pointee must be an integer type whose bit width
4734 is a power of two greater than or equal to eight and less than or equal
4735 to a target-specific size limit. <code>align</code> must be explicitly
4736 specified on atomic loads, and the load has undefined behavior if the
4737 alignment is not set to a value which is at least the size in bytes of
4738 the pointee. <code>!nontemporal</code> does not have any defined semantics
4739 for atomic loads.</p>
4740
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4741<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4742 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4743 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4744 alignment for the target. It is the responsibility of the code emitter to
4745 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4746 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4747 produce less efficient code. An alignment of 1 is always safe.</p>
4748
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4749<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4750 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4751 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4752 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4753 and code generator that this load is not expected to be reused in the cache.
4754 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4755 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4756
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4757<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4758<p>The location of memory pointed to is loaded. If the value being loaded is of
4759 scalar type then the number of bytes read does not exceed the minimum number
4760 of bytes needed to hold all bits of the type. For example, loading an
4761 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4762 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4763 is undefined if the value was not originally written using a store of the
4764 same type.</p>
4765
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4766<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4767<pre>
4768 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4769 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4770 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4771</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4772
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4773</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4774
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4775<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4776<h4>
4777 <a name="i_store">'<tt>store</tt>' Instruction</a>
4778</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4779
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4780<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4782<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4784 store [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4785 store atomic [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4786</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4787
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4788<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4789<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4790
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4791<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4792<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4793 and an address at which to store it. The type of the
4794 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4795 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4796 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4797 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4798 order of execution of this <tt>store</tt> with other <a
4799 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4800
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4801<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4802 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4803 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4804 valid on <code>store</code> instructions. Atomic loads produce <a
4805 href="#memorymodel">defined</a> results when they may see multiple atomic
4806 stores. The type of the pointee must be an integer type whose bit width
4807 is a power of two greater than or equal to eight and less than or equal
4808 to a target-specific size limit. <code>align</code> must be explicitly
4809 specified on atomic stores, and the store has undefined behavior if the
4810 alignment is not set to a value which is at least the size in bytes of
4811 the pointee. <code>!nontemporal</code> does not have any defined semantics
4812 for atomic stores.</p>
4813
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4814<p>The optional constant "align" argument specifies the alignment of the
4815 operation (that is, the alignment of the memory address). A value of 0 or an
4816 omitted "align" argument means that the operation has the preferential
4817 alignment for the target. It is the responsibility of the code emitter to
4818 ensure that the alignment information is correct. Overestimating the
4819 alignment results in an undefined behavior. Underestimating the alignment may
4820 produce less efficient code. An alignment of 1 is always safe.</p>
4821
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4822<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4823 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4824 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4825 instruction tells the optimizer and code generator that this load is
4826 not expected to be reused in the cache. The code generator may
4827 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4828 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4829
4830
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4831<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4832<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4833 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4834 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4835 does not exceed the minimum number of bytes needed to hold all bits of the
4836 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4837 writing a value of a type like <tt>i20</tt> with a size that is not an
4838 integral number of bytes, it is unspecified what happens to the extra bits
4839 that do not belong to the type, but they will typically be overwritten.</p>
4840
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4841<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4842<pre>
4843 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4844 store i32 3, i32* %ptr <i>; yields {void}</i>
4845 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4846</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4847
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4848</div>
4849
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4850<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4851<h4>
4852<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4853</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4854
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4855<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4856
4857<h5>Syntax:</h5>
4858<pre>
4859 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4860</pre>
4861
4862<h5>Overview:</h5>
4863<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4864between operations.</p>
4865
4866<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4867href="#ordering">ordering</a> argument which defines what
4868<i>synchronizes-with</i> edges they add. They can only be given
4869<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4870<code>seq_cst</code> orderings.</p>
4871
4872<h5>Semantics:</h5>
4873<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4874semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4875<code>acquire</code> ordering semantics if and only if there exist atomic
4876operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4877<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4878<var>X</var> modifies <var>M</var> (either directly or through some side effect
4879of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4880<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4881<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4882than an explicit <code>fence</code>, one (but not both) of the atomic operations
4883<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4884<code>acquire</code> (resp.) ordering constraint and still
4885<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4886<i>happens-before</i> edge.</p>
4887
4888<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4889having both <code>acquire</code> and <code>release</code> semantics specified
4890above, participates in the global program order of other <code>seq_cst</code>
4891operations and/or fences.</p>
4892
4893<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4894specifies that the fence only synchronizes with other fences in the same
4895thread. (This is useful for interacting with signal handlers.)</p>
4896
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4897<h5>Example:</h5>
4898<pre>
4899 fence acquire <i>; yields {void}</i>
4900 fence singlethread seq_cst <i>; yields {void}</i>
4901</pre>
4902
4903</div>
4904
4905<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4906<h4>
4907<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4908</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4909
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4910<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4911
4912<h5>Syntax:</h5>
4913<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4914 cmpxchg [volatile] &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;cmp&gt;, &lt;ty&gt; &lt;new&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4915</pre>
4916
4917<h5>Overview:</h5>
4918<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4919It loads a value in memory and compares it to a given value. If they are
4920equal, it stores a new value into the memory.</p>
4921
4922<h5>Arguments:</h5>
4923<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4924address to operate on, a value to compare to the value currently be at that
4925address, and a new value to place at that address if the compared values are
4926equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4927bit width is a power of two greater than or equal to eight and less than
4928or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4929'<var>&lt;new&gt;</var>' must have the same type, and the type of
4930'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4931<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4932optimizer is not allowed to modify the number or order of execution
4933of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4934operations</a>.</p>
4935
4936<!-- FIXME: Extend allowed types. -->
4937
4938<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4939<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4940
4941<p>The optional "<code>singlethread</code>" argument declares that the
4942<code>cmpxchg</code> is only atomic with respect to code (usually signal
4943handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4944cmpxchg is atomic with respect to all other code in the system.</p>
4945
4946<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4947the size in memory of the operand.
4948
4949<h5>Semantics:</h5>
4950<p>The contents of memory at the location specified by the
4951'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4952'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4953'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4954is returned.
4955
4956<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4957purpose of identifying <a href="#release_sequence">release sequences</a>. A
4958failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4959parameter determined by dropping any <code>release</code> part of the
4960<code>cmpxchg</code>'s ordering.</p>
4961
4962<!--
4963FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4964optimization work on ARM.)
4965
4966FIXME: Is a weaker ordering constraint on failure helpful in practice?
4967-->
4968
4969<h5>Example:</h5>
4970<pre>
4971entry:
4972 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4973 <a href="#i_br">br</a> label %loop
4974
4975loop:
4976 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4977 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4978 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4979 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4980 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4981
4982done:
4983 ...
4984</pre>
4985
4986</div>
4987
4988<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4989<h4>
4990<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4991</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4992
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4993<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4994
4995<h5>Syntax:</h5>
4996<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4997 atomicrmw [volatile] &lt;operation&gt; &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;value&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4998</pre>
4999
5000<h5>Overview:</h5>
5001<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5002
5003<h5>Arguments:</h5>
5004<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5005operation to apply, an address whose value to modify, an argument to the
5006operation. The operation must be one of the following keywords:</p>
5007<ul>
5008 <li>xchg</li>
5009 <li>add</li>
5010 <li>sub</li>
5011 <li>and</li>
5012 <li>nand</li>
5013 <li>or</li>
5014 <li>xor</li>
5015 <li>max</li>
5016 <li>min</li>
5017 <li>umax</li>
5018 <li>umin</li>
5019</ul>
5020
5021<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5022bit width is a power of two greater than or equal to eight and less than
5023or equal to a target-specific size limit. The type of the
5024'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5025If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5026optimizer is not allowed to modify the number or order of execution of this
5027<code>atomicrmw</code> with other <a href="#volatile">volatile
5028 operations</a>.</p>
5029
5030<!-- FIXME: Extend allowed types. -->
5031
5032<h5>Semantics:</h5>
5033<p>The contents of memory at the location specified by the
5034'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5035back. The original value at the location is returned. The modification is
5036specified by the <var>operation</var> argument:</p>
5037
5038<ul>
5039 <li>xchg: <code>*ptr = val</code></li>
5040 <li>add: <code>*ptr = *ptr + val</code></li>
5041 <li>sub: <code>*ptr = *ptr - val</code></li>
5042 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5043 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5044 <li>or: <code>*ptr = *ptr | val</code></li>
5045 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5046 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5047 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5048 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5049 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5050</ul>
5051
5052<h5>Example:</h5>
5053<pre>
5054 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5055</pre>
5056
5057</div>
5058
5059<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5060<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5061 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5062</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5063
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5064<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5065
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5066<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5067<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5068 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5069 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5070</pre>
5071
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5072<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5073<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5074 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5075 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5076
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5077<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5078<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5079 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080 elements of the aggregate object are indexed. The interpretation of each
5081 index is dependent on the type being indexed into. The first index always
5082 indexes the pointer value given as the first argument, the second index
5083 indexes a value of the type pointed to (not necessarily the value directly
5084 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5085 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5086 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5087 can never be pointers, since that would require loading the pointer before
5088 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5089
5090<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5091 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5092 integer <b>constants</b> are allowed. When indexing into an array, pointer
5093 or vector, integers of any width are allowed, and they are not required to be
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5094 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5095
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5096<p>For example, let's consider a C code fragment and how it gets compiled to
5097 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5098
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5099<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5100struct RT {
5101 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5102 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5103 char C;
5104};
5105struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5106 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5107 double Y;
5108 struct RT Z;
5109};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5110
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5111int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5112 return &amp;s[1].Z.B[5][13];
5113}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5114</pre>
5115
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5116<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5117
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5118<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]5119%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5120%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5121
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5122define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5123entry:
5124 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5125 ret i32* %reg
5126}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5127</pre>
5128
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5129<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5130<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5131 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5132 }</tt>' type, a structure. The second index indexes into the third element
5133 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5134 i8 }</tt>' type, another structure. The third index indexes into the second
5135 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5136 array. The two dimensions of the array are subscripted into, yielding an
5137 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5138 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5139
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5140<p>Note that it is perfectly legal to index partially through a structure,
5141 returning a pointer to an inner element. Because of this, the LLVM code for
5142 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5143
5144<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5145 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5146 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]5147 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5148 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5149 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5150 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5151 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5152 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5153</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5154
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5155<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5156 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5157 base pointer is not an <i>in bounds</i> address of an allocated object,
5158 or if any of the addresses that would be formed by successive addition of
5159 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5160 precise signed arithmetic are not an <i>in bounds</i> address of that
5161 allocated object. The <i>in bounds</i> addresses for an allocated object
5162 are all the addresses that point into the object, plus the address one
5163 byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5164
5165<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5166 the base address with silently-wrapping two's complement arithmetic. If the
5167 offsets have a different width from the pointer, they are sign-extended or
5168 truncated to the width of the pointer. The result value of the
5169 <tt>getelementptr</tt> may be outside the object pointed to by the base
5170 pointer. The result value may not necessarily be used to access memory
5171 though, even if it happens to point into allocated storage. See the
5172 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5173 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5174
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5175<p>The getelementptr instruction is often confusing. For some more insight into
5176 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5177
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5178<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5179<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5180 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5181 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5182 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5183 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5184 <i>; yields i8*:eptr</i>
5185 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5186 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5187 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5188</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5189
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5190</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5191
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5192</div>
5193
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5194<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5195<h3>
5196 <a name="convertops">Conversion Operations</a>
5197</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5198
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5199<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5200
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5201<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5202 which all take a single operand and a type. They perform various bit
5203 conversions on the operand.</p>
5204
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5205<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5206<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5207 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5208</h4>
5209
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5210<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5211
5212<h5>Syntax:</h5>
5213<pre>
5214 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5215</pre>
5216
5217<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5218<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5219 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5220
5221<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5222<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5223 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5224 of the same number of integers.
5225 The bit size of the <tt>value</tt> must be larger than
5226 the bit size of the destination type, <tt>ty2</tt>.
5227 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5228
5229<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5230<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5231 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5232 source size must be larger than the destination size, <tt>trunc</tt> cannot
5233 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5234
5235<h5>Example:</h5>
5236<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5237 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5238 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5239 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5240 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5241</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5242
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5243</div>
5244
5245<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5246<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5247 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5248</h4>
5249
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5250<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5251
5252<h5>Syntax:</h5>
5253<pre>
5254 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5255</pre>
5256
5257<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5258<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5259 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5260
5261
5262<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5263<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5264 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5265 of the same number of integers.
5266 The bit size of the <tt>value</tt> must be smaller than
5267 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5268 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5269
5270<h5>Semantics:</h5>
5271<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5272 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5273
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5274<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5275
5276<h5>Example:</h5>
5277<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5278 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5279 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5280 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5281</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5282
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5283</div>
5284
5285<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5286<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5287 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5288</h4>
5289
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5290<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5291
5292<h5>Syntax:</h5>
5293<pre>
5294 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5295</pre>
5296
5297<h5>Overview:</h5>
5298<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5299
5300<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5301<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5302 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5303 of the same number of integers.
5304 The bit size of the <tt>value</tt> must be smaller than
5305 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5306 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5307
5308<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5309<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5310 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5311 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5312
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5313<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5314
5315<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5316<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5317 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5318 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5319 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5320</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5321
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5322</div>
5323
5324<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5325<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5326 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5327</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5328
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5329<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5330
5331<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5332<pre>
5333 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5334</pre>
5335
5336<h5>Overview:</h5>
5337<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5338 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5339
5340<h5>Arguments:</h5>
5341<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5342 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5343 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5344 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5345 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5346
5347<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5348<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5349 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5350 <a href="#t_floating">floating point</a> type. If the value cannot fit
5351 within the destination type, <tt>ty2</tt>, then the results are
5352 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5353
5354<h5>Example:</h5>
5355<pre>
5356 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5357 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5358</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5359
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5360</div>
5361
5362<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5363<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5364 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5365</h4>
5366
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5367<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5368
5369<h5>Syntax:</h5>
5370<pre>
5371 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5372</pre>
5373
5374<h5>Overview:</h5>
5375<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5376 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5377
5378<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5379<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5380 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5381 a <a href="#t_floating">floating point</a> type to cast it to. The source
5382 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5383
5384<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5385<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5386 <a href="#t_floating">floating point</a> type to a larger
5387 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5388 used to make a <i>no-op cast</i> because it always changes bits. Use
5389 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5390
5391<h5>Example:</h5>
5392<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5393 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5394 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5395</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5396
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5397</div>
5398
5399<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5400<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5401 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5402</h4>
5403
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5404<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5405
5406<h5>Syntax:</h5>
5407<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5408 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5409</pre>
5410
5411<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5412<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5413 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5414
5415<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5416<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5417 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5418 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5419 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5420 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5421
5422<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5423<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5424 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5425 towards zero) unsigned integer value. If the value cannot fit
5426 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5427
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5428<h5>Example:</h5>
5429<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5430 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5431 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5432 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5433</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5434
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5435</div>
5436
5437<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5438<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5439 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5440</h4>
5441
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5442<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5443
5444<h5>Syntax:</h5>
5445<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5446 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5447</pre>
5448
5449<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5450<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5451 <a href="#t_floating">floating point</a> <tt>value</tt> to
5452 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5453
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5454<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5455<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5456 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5457 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5458 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5459 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5460
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5461<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5462<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5463 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5464 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5465 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5466
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5467<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5468<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5469 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5470 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5471 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5472</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5473
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5474</div>
5475
5476<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5477<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5478 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5479</h4>
5480
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5481<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5482
5483<h5>Syntax:</h5>
5484<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5485 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5486</pre>
5487
5488<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5489<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5490 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5491
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5492<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5493<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5494 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5495 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5496 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5497 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5498
5499<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5500<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5501 integer quantity and converts it to the corresponding floating point
5502 value. If the value cannot fit in the floating point value, the results are
5503 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5504
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5505<h5>Example:</h5>
5506<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5507 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5508 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5509</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5510
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5511</div>
5512
5513<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5514<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5515 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5516</h4>
5517
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5518<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5519
5520<h5>Syntax:</h5>
5521<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5522 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5523</pre>
5524
5525<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5526<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5527 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5528
5529<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5530<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5531 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5532 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5533 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5534 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5535
5536<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5537<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5538 quantity and converts it to the corresponding floating point value. If the
5539 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5540
5541<h5>Example:</h5>
5542<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5543 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5544 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5545</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5546
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5547</div>
5548
5549<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5550<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5551 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5552</h4>
5553
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5554<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5555
5556<h5>Syntax:</h5>
5557<pre>
5558 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5559</pre>
5560
5561<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5562<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5563 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5564
5565<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5566<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5567 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5568 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5569
5570<h5>Semantics:</h5>
5571<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5572 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5573 truncating or zero extending that value to the size of the integer type. If
5574 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5575 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5576 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5577 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5578
5579<h5>Example:</h5>
5580<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5581 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5582 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5583</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5584
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5585</div>
5586
5587<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5588<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5589 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5590</h4>
5591
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5592<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5593
5594<h5>Syntax:</h5>
5595<pre>
5596 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5597</pre>
5598
5599<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5600<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5601 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5602
5603<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5604<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5605 value to cast, and a type to cast it to, which must be a
5606 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5607
5608<h5>Semantics:</h5>
5609<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5610 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5611 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5612 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5613 than the size of a pointer then a zero extension is done. If they are the
5614 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5615
5616<h5>Example:</h5>
5617<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5618 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5619 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5620 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5621</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5622
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5623</div>
5624
5625<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5626<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5627 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5628</h4>
5629
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5630<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5631
5632<h5>Syntax:</h5>
5633<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5634 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5635</pre>
5636
5637<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5638<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5639 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5640
5641<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5642<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5643 non-aggregate first class value, and a type to cast it to, which must also be
5644 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5645 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5646 identical. If the source type is a pointer, the destination type must also be
5647 a pointer. This instruction supports bitwise conversion of vectors to
5648 integers and to vectors of other types (as long as they have the same
5649 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5650
5651<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5652<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5653 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5654 this conversion. The conversion is done as if the <tt>value</tt> had been
5655 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5656 be converted to other pointer types with this instruction. To convert
5657 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5658 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5659
5660<h5>Example:</h5>
5661<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5662 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5663 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5664 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5665</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5666
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5667</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5668
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5669</div>
5670
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5671<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5672<h3>
5673 <a name="otherops">Other Operations</a>
5674</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5675
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5676<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5677
5678<p>The instructions in this category are the "miscellaneous" instructions, which
5679 defy better classification.</p>
5680
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5681<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5682<h4>
5683 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5684</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5685
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5686<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5687
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5688<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5689<pre>
5690 &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 Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5691</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5692
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5693<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5694<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5695 boolean values based on comparison of its two integer, integer vector, or
5696 pointer operands.</p>
5697
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5698<h5>Arguments:</h5>
5699<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5700 the condition code indicating the kind of comparison to perform. It is not a
5701 value, just a keyword. The possible condition code are:</p>
5702
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5703<ol>
5704 <li><tt>eq</tt>: equal</li>
5705 <li><tt>ne</tt>: not equal </li>
5706 <li><tt>ugt</tt>: unsigned greater than</li>
5707 <li><tt>uge</tt>: unsigned greater or equal</li>
5708 <li><tt>ult</tt>: unsigned less than</li>
5709 <li><tt>ule</tt>: unsigned less or equal</li>
5710 <li><tt>sgt</tt>: signed greater than</li>
5711 <li><tt>sge</tt>: signed greater or equal</li>
5712 <li><tt>slt</tt>: signed less than</li>
5713 <li><tt>sle</tt>: signed less or equal</li>
5714</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5715
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5716<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5717 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5718 typed. They must also be identical types.</p>
5719
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5720<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5721<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5722 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5723 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5724 result, as follows:</p>
5725
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5726<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5727 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5728 <tt>false</tt> otherwise. No sign interpretation is necessary or
5729 performed.</li>
5730
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5731 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5732 <tt>false</tt> otherwise. No sign interpretation is necessary or
5733 performed.</li>
5734
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5735 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5736 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5737
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5738 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5739 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5740 to <tt>op2</tt>.</li>
5741
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5742 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5743 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5744
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5745 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5746 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5747
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5748 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5749 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5750
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5751 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5752 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5753 to <tt>op2</tt>.</li>
5754
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5755 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5756 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5757
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5758 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5759 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5760</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5762<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5763 values are compared as if they were integers.</p>
5764
5765<p>If the operands are integer vectors, then they are compared element by
5766 element. The result is an <tt>i1</tt> vector with the same number of elements
5767 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5768
5769<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5770<pre>
5771 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5772 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5773 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5774 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5775 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5776 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5777</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5778
5779<p>Note that the code generator does not yet support vector types with
5780 the <tt>icmp</tt> instruction.</p>
5781
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5782</div>
5783
5784<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5785<h4>
5786 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5787</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5788
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5789<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5790
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5791<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792<pre>
5793 &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 Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5794</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5795
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5796<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5797<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5798 values based on comparison of its operands.</p>
5799
5800<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5801(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5802
5803<p>If the operands are floating point vectors, then the result type is a vector
5804 of boolean with the same number of elements as the operands being
5805 compared.</p>
5806
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5807<h5>Arguments:</h5>
5808<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5809 the condition code indicating the kind of comparison to perform. It is not a
5810 value, just a keyword. The possible condition code are:</p>
5811
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5812<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5813 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5814 <li><tt>oeq</tt>: ordered and equal</li>
5815 <li><tt>ogt</tt>: ordered and greater than </li>
5816 <li><tt>oge</tt>: ordered and greater than or equal</li>
5817 <li><tt>olt</tt>: ordered and less than </li>
5818 <li><tt>ole</tt>: ordered and less than or equal</li>
5819 <li><tt>one</tt>: ordered and not equal</li>
5820 <li><tt>ord</tt>: ordered (no nans)</li>
5821 <li><tt>ueq</tt>: unordered or equal</li>
5822 <li><tt>ugt</tt>: unordered or greater than </li>
5823 <li><tt>uge</tt>: unordered or greater than or equal</li>
5824 <li><tt>ult</tt>: unordered or less than </li>
5825 <li><tt>ule</tt>: unordered or less than or equal</li>
5826 <li><tt>une</tt>: unordered or not equal</li>
5827 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5828 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5829</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5830
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5831<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832 <i>unordered</i> means that either operand may be a QNAN.</p>
5833
5834<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5835 a <a href="#t_floating">floating point</a> type or
5836 a <a href="#t_vector">vector</a> of floating point type. They must have
5837 identical types.</p>
5838
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5839<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5840<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5841 according to the condition code given as <tt>cond</tt>. If the operands are
5842 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5843 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5844 follows:</p>
5845
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5846<ol>
5847 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5848
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5849 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5851
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5852 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5853 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5854
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5855 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5856 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5857
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5858 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5859 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5860
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5861 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5862 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5863
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5864 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5865 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5866
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5867 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5868
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5869 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5870 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5871
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5872 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5873 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5874
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5875 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5876 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5877
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5878 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5879 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5880
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5881 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5882 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5883
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5884 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5885 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5886
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5887 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5888
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5889 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5890</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5891
5892<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5893<pre>
5894 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5895 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5896 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5897 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5898</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5899
5900<p>Note that the code generator does not yet support vector types with
5901 the <tt>fcmp</tt> instruction.</p>
5902
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5903</div>
5904
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5905<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5906<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5907 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5908</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5909
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5910<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5911
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5912<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5913<pre>
5914 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5915</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5916
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5917<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5918<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5919 SSA graph representing the function.</p>
5920
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5921<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5922<p>The type of the incoming values is specified with the first type field. After
5923 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5924 one pair for each predecessor basic block of the current block. Only values
5925 of <a href="#t_firstclass">first class</a> type may be used as the value
5926 arguments to the PHI node. Only labels may be used as the label
5927 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5928
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p>There must be no non-phi instructions between the start of a basic block and
5930 the PHI instructions: i.e. PHI instructions must be first in a basic
5931 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5932
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5933<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5934 occur on the edge from the corresponding predecessor block to the current
5935 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5936 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5937
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5938<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5939<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5940 specified by the pair corresponding to the predecessor basic block that
5941 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5942
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5943<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5944<pre>
5945Loop: ; Infinite loop that counts from 0 on up...
5946 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5947 %nextindvar = add i32 %indvar, 1
5948 br label %Loop
5949</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5950
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5951</div>
5952
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5953<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5954<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5955 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5956</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5957
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5958<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5959
5960<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5961<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5962 &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>
5963
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5964 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5965</pre>
5966
5967<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5968<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5969 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5970
5971
5972<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5973<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5974 values indicating the condition, and two values of the
5975 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5976 vectors and the condition is a scalar, then entire vectors are selected, not
5977 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5978
5979<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5980<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5981 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5982
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5983<p>If the condition is a vector of i1, then the value arguments must be vectors
5984 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5985
5986<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5987<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5988 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5989</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5990
5991<p>Note that the code generator does not yet support conditions
5992 with vector type.</p>
5993
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5994</div>
5995
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5996<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5997<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5998 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5999</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6000
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6001<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6002
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6003<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6004<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6005 &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 Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6006</pre>
6007
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6008<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6009<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6010
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6011<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6012<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6013
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6014<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6015 <li>The optional "tail" marker indicates that the callee function does not
6016 access any allocas or varargs in the caller. Note that calls may be
6017 marked "tail" even if they do not occur before
6018 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6019 present, the function call is eligible for tail call optimization,
6020 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6021 optimized into a jump</a>. The code generator may optimize calls marked
6022 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6023 sibling call optimization</a> when the caller and callee have
6024 matching signatures, or 2) forced tail call optimization when the
6025 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6026 <ul>
6027 <li>Caller and callee both have the calling
6028 convention <tt>fastcc</tt>.</li>
6029 <li>The call is in tail position (ret immediately follows call and ret
6030 uses value of call or is void).</li>
6031 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6032 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6033 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6034 constraints are met.</a></li>
6035 </ul>
6036 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6037
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6039 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6040 defaults to using C calling conventions. The calling convention of the
6041 call must match the calling convention of the target function, or else the
6042 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6043
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6044 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6045 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6046 '<tt>inreg</tt>' attributes are valid here.</li>
6047
6048 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6049 type of the return value. Functions that return no value are marked
6050 <tt><a href="#t_void">void</a></tt>.</li>
6051
6052 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6053 being invoked. The argument types must match the types implied by this
6054 signature. This type can be omitted if the function is not varargs and if
6055 the function type does not return a pointer to a function.</li>
6056
6057 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6058 be invoked. In most cases, this is a direct function invocation, but
6059 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6060 to function value.</li>
6061
6062 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6063 signature argument types and parameter attributes. All arguments must be
6064 of <a href="#t_firstclass">first class</a> type. If the function
6065 signature indicates the function accepts a variable number of arguments,
6066 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6067
6068 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6069 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6070 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6071</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6072
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6073<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6075 a specified function, with its incoming arguments bound to the specified
6076 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6077 function, control flow continues with the instruction after the function
6078 call, and the return value of the function is bound to the result
6079 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6080
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6081<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6082<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6083 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6084 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6085 %X = tail call i32 @foo() <i>; yields i32</i>
6086 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6087 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6088
6089 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6090 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6091 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6092 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6093 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6094 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6095</pre>
6096
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6097<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6098standard C99 library as being the C99 library functions, and may perform
6099optimizations or generate code for them under that assumption. This is
6100something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6101freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6102
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6103</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6104
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6105<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6106<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6107 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6108</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6109
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6110<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6111
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6112<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6113<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6114 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6115</pre>
6116
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6117<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6118<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6119 the "variable argument" area of a function call. It is used to implement the
6120 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6121
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6122<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6123<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6124 argument. It returns a value of the specified argument type and increments
6125 the <tt>va_list</tt> to point to the next argument. The actual type
6126 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6127
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6128<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6129<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6130 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6131 to the next argument. For more information, see the variable argument
6132 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6133
6134<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6135 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6136 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6137
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6138<p><tt>va_arg</tt> is an LLVM instruction instead of
6139 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6140 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6141
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6142<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6143<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6144
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6145<p>Note that the code generator does not yet fully support va_arg on many
6146 targets. Also, it does not currently support va_arg with aggregate types on
6147 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6148
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6149</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6150
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6151<!-- _______________________________________________________________________ -->
6152<h4>
6153 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6154</h4>
6155
6156<div>
6157
6158<h5>Syntax:</h5>
6159<pre>
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6160 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6161 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6162
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6163 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6164 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6165</pre>
6166
6167<h5>Overview:</h5>
6168<p>The '<tt>landingpad</tt>' instruction is used by
6169 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6170 system</a> to specify that a basic block is a landing pad &mdash; one where
6171 the exception lands, and corresponds to the code found in the
6172 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6173 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6174 re-entry to the function. The <tt>resultval</tt> has the
6175 type <tt>somety</tt>.</p>
6176
6177<h5>Arguments:</h5>
6178<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6179 function associated with the unwinding mechanism. The optional
6180 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6181
6182<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6183 or <tt>filter</tt> &mdash; and contains the global variable representing the
6184 "type" that may be caught or filtered respectively. Unlike the
6185 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6186 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6187 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6188 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6189
6190<h5>Semantics:</h5>
6191<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6192 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6193 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6194 calling conventions, how the personality function results are represented in
6195 LLVM IR is target specific.</p>
6196
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6197<p>The clauses are applied in order from top to bottom. If two
6198 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendlinga503fc02011-08-08 07:58:58 +0000[diff] [blame]6199 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6200
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6201<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6202
6203<ul>
6204 <li>A landing pad block is a basic block which is the unwind destination of an
6205 '<tt>invoke</tt>' instruction.</li>
6206 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6207 first non-PHI instruction.</li>
6208 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6209 pad block.</li>
6210 <li>A basic block that is not a landing pad block may not include a
6211 '<tt>landingpad</tt>' instruction.</li>
6212 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6213 personality function.</li>
6214</ul>
6215
6216<h5>Example:</h5>
6217<pre>
6218 ;; A landing pad which can catch an integer.
6219 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6220 catch i8** @_ZTIi
6221 ;; A landing pad that is a cleanup.
6222 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6223 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6224 ;; A landing pad which can catch an integer and can only throw a double.
6225 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6226 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6227 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6228</pre>
6229
6230</div>
6231
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6232</div>
6233
6234</div>
6235
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6236<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6237<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6238<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6239
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6240<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6241
6242<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243 well known names and semantics and are required to follow certain
6244 restrictions. Overall, these intrinsics represent an extension mechanism for
6245 the LLVM language that does not require changing all of the transformations
6246 in LLVM when adding to the language (or the bitcode reader/writer, the
6247 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6248
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6249<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6250 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6251 begin with this prefix. Intrinsic functions must always be external
6252 functions: you cannot define the body of intrinsic functions. Intrinsic
6253 functions may only be used in call or invoke instructions: it is illegal to
6254 take the address of an intrinsic function. Additionally, because intrinsic
6255 functions are part of the LLVM language, it is required if any are added that
6256 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6257
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6258<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6259 family of functions that perform the same operation but on different data
6260 types. Because LLVM can represent over 8 million different integer types,
6261 overloading is used commonly to allow an intrinsic function to operate on any
6262 integer type. One or more of the argument types or the result type can be
6263 overloaded to accept any integer type. Argument types may also be defined as
6264 exactly matching a previous argument's type or the result type. This allows
6265 an intrinsic function which accepts multiple arguments, but needs all of them
6266 to be of the same type, to only be overloaded with respect to a single
6267 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6268
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6269<p>Overloaded intrinsics will have the names of its overloaded argument types
6270 encoded into its function name, each preceded by a period. Only those types
6271 which are overloaded result in a name suffix. Arguments whose type is matched
6272 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6273 can take an integer of any width and returns an integer of exactly the same
6274 integer width. This leads to a family of functions such as
6275 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6276 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6277 suffix is required. Because the argument's type is matched against the return
6278 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6279
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6280<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6281 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6282
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6283<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6284<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6285 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6286</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6287
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6288<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6289
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6290<p>Variable argument support is defined in LLVM with
6291 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6292 intrinsic functions. These functions are related to the similarly named
6293 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6294
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6295<p>All of these functions operate on arguments that use a target-specific value
6296 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6297 not define what this type is, so all transformations should be prepared to
6298 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6299
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6300<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6301 instruction and the variable argument handling intrinsic functions are
6302 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6303
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6304<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6305define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6306 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6307 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6308 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6309 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6310
6311 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6312 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6313
6314 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6315 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6316 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6317 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6318 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6319
6320 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6321 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6322 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6323}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6324
6325declare void @llvm.va_start(i8*)
6326declare void @llvm.va_copy(i8*, i8*)
6327declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6328</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6329
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6330<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6331<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6332 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6333</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6334
6335
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6336<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6337
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6338<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339<pre>
6340 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6341</pre>
6342
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6343<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6344<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6345 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6346
6347<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6348<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6349
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6350<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6351<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6352 macro available in C. In a target-dependent way, it initializes
6353 the <tt>va_list</tt> element to which the argument points, so that the next
6354 call to <tt>va_arg</tt> will produce the first variable argument passed to
6355 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6356 need to know the last argument of the function as the compiler can figure
6357 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6358
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6359</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6360
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6361<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6362<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6363 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6364</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6365
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6366<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6368<h5>Syntax:</h5>
6369<pre>
6370 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6371</pre>
6372
6373<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6374<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6375 which has been initialized previously
6376 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6377 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6378
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6379<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6380<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6381
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6382<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6383<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6384 macro available in C. In a target-dependent way, it destroys
6385 the <tt>va_list</tt> element to which the argument points. Calls
6386 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6387 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6388 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6389
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6390</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6391
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6392<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6393<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6394 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6395</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6396
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6397<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6398
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6399<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6400<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6401 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6402</pre>
6403
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6404<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6405<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6406 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6407
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6408<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6409<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6410 The second argument is a pointer to a <tt>va_list</tt> element to copy
6411 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6412
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6413<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6414<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6415 macro available in C. In a target-dependent way, it copies the
6416 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6417 element. This intrinsic is necessary because
6418 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6419 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6420
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6421</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6422
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6423</div>
6424
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6425<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6426<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6427 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6428</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6429
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6430<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6431
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6432<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6433Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6434intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6435roots on the stack</a>, as well as garbage collector implementations that
6436require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6437barriers. Front-ends for type-safe garbage collected languages should generate
6438these intrinsics to make use of the LLVM garbage collectors. For more details,
6439see <a href="GarbageCollection.html">Accurate Garbage Collection with
6440LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6441
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6442<p>The garbage collection intrinsics only operate on objects in the generic
6443 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6444
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6445<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6446<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6447 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6448</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6449
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6450<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6451
6452<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6453<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6454 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6455</pre>
6456
6457<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6458<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6459 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6460
6461<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6462<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6463 root pointer. The second pointer (which must be either a constant or a
6464 global value address) contains the meta-data to be associated with the
6465 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6466
6467<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6468<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6469 location. At compile-time, the code generator generates information to allow
6470 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6471 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6472 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6473
6474</div>
6475
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6476<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6477<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6478 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6479</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6480
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6481<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6482
6483<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6484<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6485 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6486</pre>
6487
6488<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6489<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6490 locations, allowing garbage collector implementations that require read
6491 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6492
6493<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6494<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6495 allocated from the garbage collector. The first object is a pointer to the
6496 start of the referenced object, if needed by the language runtime (otherwise
6497 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6498
6499<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6500<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6501 instruction, but may be replaced with substantially more complex code by the
6502 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6503 may only be used in a function which <a href="#gc">specifies a GC
6504 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6505
6506</div>
6507
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6508<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6509<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6510 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6511</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6512
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6513<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6514
6515<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6516<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6517 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6518</pre>
6519
6520<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6521<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6522 locations, allowing garbage collector implementations that require write
6523 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6524
6525<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6526<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6527 object to store it to, and the third is the address of the field of Obj to
6528 store to. If the runtime does not require a pointer to the object, Obj may
6529 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6530
6531<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6532<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6533 instruction, but may be replaced with substantially more complex code by the
6534 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6535 may only be used in a function which <a href="#gc">specifies a GC
6536 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6537
6538</div>
6539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6540</div>
6541
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6542<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6543<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6544 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6545</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6546
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6547<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6548
6549<p>These intrinsics are provided by LLVM to expose special features that may
6550 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6551
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6552<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6553<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6554 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6555</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6556
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6557<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6558
6559<h5>Syntax:</h5>
6560<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6561 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6562</pre>
6563
6564<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6565<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6566 target-specific value indicating the return address of the current function
6567 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6568
6569<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6570<p>The argument to this intrinsic indicates which function to return the address
6571 for. Zero indicates the calling function, one indicates its caller, etc.
6572 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6573
6574<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6575<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6576 indicating the return address of the specified call frame, or zero if it
6577 cannot be identified. The value returned by this intrinsic is likely to be
6578 incorrect or 0 for arguments other than zero, so it should only be used for
6579 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6580
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6581<p>Note that calling this intrinsic does not prevent function inlining or other
6582 aggressive transformations, so the value returned may not be that of the
6583 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6584
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6585</div>
6586
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6587<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6588<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6589 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6590</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6591
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6592<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6593
6594<h5>Syntax:</h5>
6595<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6596 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6597</pre>
6598
6599<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6600<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6601 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6602
6603<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6604<p>The argument to this intrinsic indicates which function to return the frame
6605 pointer for. Zero indicates the calling function, one indicates its caller,
6606 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6607
6608<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6609<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6610 indicating the frame address of the specified call frame, or zero if it
6611 cannot be identified. The value returned by this intrinsic is likely to be
6612 incorrect or 0 for arguments other than zero, so it should only be used for
6613 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6614
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6615<p>Note that calling this intrinsic does not prevent function inlining or other
6616 aggressive transformations, so the value returned may not be that of the
6617 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6618
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6619</div>
6620
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6621<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6622<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6623 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6624</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6625
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6626<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6627
6628<h5>Syntax:</h5>
6629<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6630 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6631</pre>
6632
6633<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6634<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6635 of the function stack, for use
6636 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6637 useful for implementing language features like scoped automatic variable
6638 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6639
6640<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6641<p>This intrinsic returns a opaque pointer value that can be passed
6642 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6643 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6644 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6645 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6646 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6647 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6648
6649</div>
6650
6651<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6652<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6653 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6654</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6655
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6656<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6657
6658<h5>Syntax:</h5>
6659<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6660 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6661</pre>
6662
6663<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6664<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6665 the function stack to the state it was in when the
6666 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6667 executed. This is useful for implementing language features like scoped
6668 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6669
6670<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6671<p>See the description
6672 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6673
6674</div>
6675
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6676<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6677<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6678 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6679</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6680
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6681<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6682
6683<h5>Syntax:</h5>
6684<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6685 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6686</pre>
6687
6688<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6689<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6690 insert a prefetch instruction if supported; otherwise, it is a noop.
6691 Prefetches have no effect on the behavior of the program but can change its
6692 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6693
6694<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6695<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6696 specifier determining if the fetch should be for a read (0) or write (1),
6697 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6698 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6699 specifies whether the prefetch is performed on the data (1) or instruction (0)
6700 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6701 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6702
6703<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6704<p>This intrinsic does not modify the behavior of the program. In particular,
6705 prefetches cannot trap and do not produce a value. On targets that support
6706 this intrinsic, the prefetch can provide hints to the processor cache for
6707 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6708
6709</div>
6710
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6711<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6712<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6713 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6714</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6715
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6716<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6717
6718<h5>Syntax:</h5>
6719<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6720 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6721</pre>
6722
6723<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6724<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6725 Counter (PC) in a region of code to simulators and other tools. The method
6726 is target specific, but it is expected that the marker will use exported
6727 symbols to transmit the PC of the marker. The marker makes no guarantees
6728 that it will remain with any specific instruction after optimizations. It is
6729 possible that the presence of a marker will inhibit optimizations. The
6730 intended use is to be inserted after optimizations to allow correlations of
6731 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6732
6733<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6734<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6735
6736<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6737<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6738 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6739
6740</div>
6741
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6742<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6743<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6744 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6745</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6746
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6747<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6748
6749<h5>Syntax:</h5>
6750<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6751 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6752</pre>
6753
6754<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6755<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6756 counter register (or similar low latency, high accuracy clocks) on those
6757 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6758 should map to RPCC. As the backing counters overflow quickly (on the order
6759 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6760
6761<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6762<p>When directly supported, reading the cycle counter should not modify any
6763 memory. Implementations are allowed to either return a application specific
6764 value or a system wide value. On backends without support, this is lowered
6765 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6766
6767</div>
6768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6769</div>
6770
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6771<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6772<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6773 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6774</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6775
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6776<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6777
6778<p>LLVM provides intrinsics for a few important standard C library functions.
6779 These intrinsics allow source-language front-ends to pass information about
6780 the alignment of the pointer arguments to the code generator, providing
6781 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6782
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6783<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6784<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6785 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6786</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6787
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6788<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6789
6790<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6791<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6792 integer bit width and for different address spaces. Not all targets support
6793 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6794
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6795<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6796 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6797 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6798 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6799 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6800</pre>
6801
6802<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6803<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6804 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6805
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6806<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6807 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6808 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6809
6810<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6811
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6812<p>The first argument is a pointer to the destination, the second is a pointer
6813 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6814 number of bytes to copy, the fourth argument is the alignment of the
6815 source and destination locations, and the fifth is a boolean indicating a
6816 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6817
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6818<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6819 then the caller guarantees that both the source and destination pointers are
6820 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6821
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6822<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6823 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6824 The detailed access behavior is not very cleanly specified and it is unwise
6825 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6826
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6827<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6828
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6829<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6830 source location to the destination location, which are not allowed to
6831 overlap. It copies "len" bytes of memory over. If the argument is known to
6832 be aligned to some boundary, this can be specified as the fourth argument,
6833 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6834
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6835</div>
6836
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6837<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6838<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6839 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6840</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6841
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6842<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6843
6844<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6845<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6846 width and for different address space. Not all targets support all bit
6847 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6848
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6849<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6850 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6851 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6852 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6853 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6854</pre>
6855
6856<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6857<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6858 source location to the destination location. It is similar to the
6859 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6860 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6861
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6862<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6863 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6864 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6865
6866<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6868<p>The first argument is a pointer to the destination, the second is a pointer
6869 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6870 number of bytes to copy, the fourth argument is the alignment of the
6871 source and destination locations, and the fifth is a boolean indicating a
6872 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6873
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6874<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6875 then the caller guarantees that the source and destination pointers are
6876 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6877
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6878<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6879 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6880 The detailed access behavior is not very cleanly specified and it is unwise
6881 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6882
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6883<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6884
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6885<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6886 source location to the destination location, which may overlap. It copies
6887 "len" bytes of memory over. If the argument is known to be aligned to some
6888 boundary, this can be specified as the fourth argument, otherwise it should
6889 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6890
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6891</div>
6892
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6893<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6894<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6895 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6896</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6897
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6898<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6899
6900<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6901<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6902 width and for different address spaces. However, not all targets support all
6903 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6904
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6905<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6906 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6907 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6908 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6909 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6910</pre>
6911
6912<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6913<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6914 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6916<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6917 intrinsic does not return a value and takes extra alignment/volatile
6918 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6919
6920<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6921<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6922 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6924 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6925
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6926<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6927 then the caller guarantees that the destination pointer is aligned to that
6928 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6929
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6930<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6931 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6932 The detailed access behavior is not very cleanly specified and it is unwise
6933 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6934
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6935<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6936<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6937 at the destination location. If the argument is known to be aligned to some
6938 boundary, this can be specified as the fourth argument, otherwise it should
6939 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6940
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6941</div>
6942
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6943<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6944<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6945 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6946</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6947
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6948<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6949
6950<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6951<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6952 floating point or vector of floating point type. Not all targets support all
6953 types however.</p>
6954
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6955<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6956 declare float @llvm.sqrt.f32(float %Val)
6957 declare double @llvm.sqrt.f64(double %Val)
6958 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6959 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6960 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6961</pre>
6962
6963<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6964<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6965 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6966 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6967 behavior for negative numbers other than -0.0 (which allows for better
6968 optimization, because there is no need to worry about errno being
6969 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6970
6971<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6972<p>The argument and return value are floating point numbers of the same
6973 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6974
6975<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6976<p>This function returns the sqrt of the specified operand if it is a
6977 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6978
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6979</div>
6980
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6981<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6982<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6983 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6984</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6985
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6986<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6987
6988<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6989<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6990 floating point or vector of floating point type. Not all targets support all
6991 types however.</p>
6992
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6993<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6994 declare float @llvm.powi.f32(float %Val, i32 %power)
6995 declare double @llvm.powi.f64(double %Val, i32 %power)
6996 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6997 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6998 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6999</pre>
7000
7001<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7002<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7003 specified (positive or negative) power. The order of evaluation of
7004 multiplications is not defined. When a vector of floating point type is
7005 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7006
7007<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7008<p>The second argument is an integer power, and the first is a value to raise to
7009 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7010
7011<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7012<p>This function returns the first value raised to the second power with an
7013 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7014
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7015</div>
7016
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7017<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7018<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7019 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7020</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7021
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7022<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7023
7024<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7025<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7026 floating point or vector of floating point type. Not all targets support all
7027 types however.</p>
7028
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7029<pre>
7030 declare float @llvm.sin.f32(float %Val)
7031 declare double @llvm.sin.f64(double %Val)
7032 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7033 declare fp128 @llvm.sin.f128(fp128 %Val)
7034 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7035</pre>
7036
7037<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7038<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7039
7040<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7041<p>The argument and return value are floating point numbers of the same
7042 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7043
7044<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7045<p>This function returns the sine of the specified operand, returning the same
7046 values as the libm <tt>sin</tt> functions would, and handles error conditions
7047 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7048
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7049</div>
7050
7051<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7052<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7053 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7054</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7055
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7056<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7057
7058<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7059<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7060 floating point or vector of floating point type. Not all targets support all
7061 types however.</p>
7062
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7063<pre>
7064 declare float @llvm.cos.f32(float %Val)
7065 declare double @llvm.cos.f64(double %Val)
7066 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7067 declare fp128 @llvm.cos.f128(fp128 %Val)
7068 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7069</pre>
7070
7071<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7072<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7073
7074<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075<p>The argument and return value are floating point numbers of the same
7076 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7077
7078<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7079<p>This function returns the cosine of the specified operand, returning the same
7080 values as the libm <tt>cos</tt> functions would, and handles error conditions
7081 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7082
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7083</div>
7084
7085<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7086<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7087 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7088</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7089
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7090<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7091
7092<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7093<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7094 floating point or vector of floating point type. Not all targets support all
7095 types however.</p>
7096
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7097<pre>
7098 declare float @llvm.pow.f32(float %Val, float %Power)
7099 declare double @llvm.pow.f64(double %Val, double %Power)
7100 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7101 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7102 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7103</pre>
7104
7105<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7106<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7107 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7108
7109<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7110<p>The second argument is a floating point power, and the first is a value to
7111 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7112
7113<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7114<p>This function returns the first value raised to the second power, returning
7115 the same values as the libm <tt>pow</tt> functions would, and handles error
7116 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7117
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7118</div>
7119
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7120<!-- _______________________________________________________________________ -->
7121<h4>
7122 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7123</h4>
7124
7125<div>
7126
7127<h5>Syntax:</h5>
7128<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7129 floating point or vector of floating point type. Not all targets support all
7130 types however.</p>
7131
7132<pre>
7133 declare float @llvm.exp.f32(float %Val)
7134 declare double @llvm.exp.f64(double %Val)
7135 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7136 declare fp128 @llvm.exp.f128(fp128 %Val)
7137 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7138</pre>
7139
7140<h5>Overview:</h5>
7141<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7142
7143<h5>Arguments:</h5>
7144<p>The argument and return value are floating point numbers of the same
7145 type.</p>
7146
7147<h5>Semantics:</h5>
7148<p>This function returns the same values as the libm <tt>exp</tt> functions
7149 would, and handles error conditions in the same way.</p>
7150
7151</div>
7152
7153<!-- _______________________________________________________________________ -->
7154<h4>
7155 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7156</h4>
7157
7158<div>
7159
7160<h5>Syntax:</h5>
7161<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7162 floating point or vector of floating point type. Not all targets support all
7163 types however.</p>
7164
7165<pre>
7166 declare float @llvm.log.f32(float %Val)
7167 declare double @llvm.log.f64(double %Val)
7168 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7169 declare fp128 @llvm.log.f128(fp128 %Val)
7170 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7171</pre>
7172
7173<h5>Overview:</h5>
7174<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7175
7176<h5>Arguments:</h5>
7177<p>The argument and return value are floating point numbers of the same
7178 type.</p>
7179
7180<h5>Semantics:</h5>
7181<p>This function returns the same values as the libm <tt>log</tt> functions
7182 would, and handles error conditions in the same way.</p>
7183
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7184</div>
7185
7186<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7187<h4>
7188 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7189</h4>
7190
7191<div>
7192
7193<h5>Syntax:</h5>
7194<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7195 floating point or vector of floating point type. Not all targets support all
7196 types however.</p>
7197
7198<pre>
7199 declare float @llvm.fma.f32(float %a, float %b, float %c)
7200 declare double @llvm.fma.f64(double %a, double %b, double %c)
7201 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7202 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7203 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7204</pre>
7205
7206<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7207<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7208 operation.</p>
7209
7210<h5>Arguments:</h5>
7211<p>The argument and return value are floating point numbers of the same
7212 type.</p>
7213
7214<h5>Semantics:</h5>
7215<p>This function returns the same values as the libm <tt>fma</tt> functions
7216 would.</p>
7217
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7218</div>
7219
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7220</div>
7221
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7222<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7223<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7224 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7225</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7226
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7227<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7228
7229<p>LLVM provides intrinsics for a few important bit manipulation operations.
7230 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7231
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7232<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7233<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7234 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7235</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7236
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7237<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7238
7239<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7240<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7241 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7242
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7243<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7244 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7245 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7246 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7247</pre>
7248
7249<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7250<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7251 values with an even number of bytes (positive multiple of 16 bits). These
7252 are useful for performing operations on data that is not in the target's
7253 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7254
7255<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7256<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7257 and low byte of the input i16 swapped. Similarly,
7258 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7259 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7260 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7261 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7262 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7263 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7264
7265</div>
7266
7267<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7268<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7269 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7270</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7271
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7272<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7273
7274<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7275<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7276 width, or on any vector with integer elements. Not all targets support all
7277 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7278
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7279<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7280 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7281 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7282 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7283 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7284 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7285 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7286</pre>
7287
7288<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7289<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7290 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7291
7292<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7293<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7294 integer type, or a vector with integer elements.
7295 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7296
7297<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7298<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7299 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7300
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7301</div>
7302
7303<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7304<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7305 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7306</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7307
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7308<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7309
7310<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7311<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7312 integer bit width, or any vector whose elements are integers. Not all
7313 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7314
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7315<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7316 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7317 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7318 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7319 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7320 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7321 declare &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src;gt)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7322</pre>
7323
7324<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7325<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7326 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7327
7328<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7329<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7330 integer type, or any vector type with integer element type.
7331 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7332
7333<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7334<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7335 zeros in a variable, or within each element of the vector if the operation
7336 is of vector type. If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7337 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7338
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7339</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7340
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7341<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7342<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7343 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7344</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7345
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7346<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7347
7348<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7349<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7350 integer bit width, or any vector of integer elements. Not all targets
7351 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7352
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7353<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7354 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7355 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7356 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7357 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7358 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7359 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7360</pre>
7361
7362<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7363<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7364 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7365
7366<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7368 integer type, or a vectory with integer element type.. The return type
7369 must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7370
7371<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7372<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7373 zeros in a variable, or within each element of a vector.
7374 If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7375 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7376
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7377</div>
7378
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7379</div>
7380
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7381<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7382<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7383 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7384</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7385
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7386<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7387
7388<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7389
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7390<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7391<h4>
7392 <a name="int_sadd_overflow">
7393 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7394 </a>
7395</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7396
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7397<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7398
7399<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7400<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7401 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7402
7403<pre>
7404 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7405 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7406 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7407</pre>
7408
7409<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7410<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7411 a signed addition of the two arguments, and indicate whether an overflow
7412 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7413
7414<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7415<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7416 be of integer types of any bit width, but they must have the same bit
7417 width. The second element of the result structure must be of
7418 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7419 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7420
7421<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7422<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7423 a signed addition of the two variables. They return a structure &mdash; the
7424 first element of which is the signed summation, and the second element of
7425 which is a bit specifying if the signed summation resulted in an
7426 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7427
7428<h5>Examples:</h5>
7429<pre>
7430 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7431 %sum = extractvalue {i32, i1} %res, 0
7432 %obit = extractvalue {i32, i1} %res, 1
7433 br i1 %obit, label %overflow, label %normal
7434</pre>
7435
7436</div>
7437
7438<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7439<h4>
7440 <a name="int_uadd_overflow">
7441 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7442 </a>
7443</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7444
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7445<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7446
7447<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7448<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7449 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7450
7451<pre>
7452 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7453 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7454 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7455</pre>
7456
7457<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7458<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7459 an unsigned addition of the two arguments, and indicate whether a carry
7460 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7461
7462<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7463<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7464 be of integer types of any bit width, but they must have the same bit
7465 width. The second element of the result structure must be of
7466 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7467 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7468
7469<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7470<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7471 an unsigned addition of the two arguments. They return a structure &mdash;
7472 the first element of which is the sum, and the second element of which is a
7473 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7474
7475<h5>Examples:</h5>
7476<pre>
7477 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7478 %sum = extractvalue {i32, i1} %res, 0
7479 %obit = extractvalue {i32, i1} %res, 1
7480 br i1 %obit, label %carry, label %normal
7481</pre>
7482
7483</div>
7484
7485<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7486<h4>
7487 <a name="int_ssub_overflow">
7488 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7489 </a>
7490</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7491
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7492<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7493
7494<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7495<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7496 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7497
7498<pre>
7499 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7500 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7501 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7502</pre>
7503
7504<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7505<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7506 a signed subtraction of the two arguments, and indicate whether an overflow
7507 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7508
7509<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7510<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7511 be of integer types of any bit width, but they must have the same bit
7512 width. The second element of the result structure must be of
7513 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7514 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7515
7516<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7517<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7518 a signed subtraction of the two arguments. They return a structure &mdash;
7519 the first element of which is the subtraction, and the second element of
7520 which is a bit specifying if the signed subtraction resulted in an
7521 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7522
7523<h5>Examples:</h5>
7524<pre>
7525 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7526 %sum = extractvalue {i32, i1} %res, 0
7527 %obit = extractvalue {i32, i1} %res, 1
7528 br i1 %obit, label %overflow, label %normal
7529</pre>
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7534<h4>
7535 <a name="int_usub_overflow">
7536 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7537 </a>
7538</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7540<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7541
7542<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7543<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7544 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7545
7546<pre>
7547 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7548 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7549 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7550</pre>
7551
7552<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7553<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7554 an unsigned subtraction of the two arguments, and indicate whether an
7555 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7556
7557<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7558<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7559 be of integer types of any bit width, but they must have the same bit
7560 width. The second element of the result structure must be of
7561 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7562 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7563
7564<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7565<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7566 an unsigned subtraction of the two arguments. They return a structure &mdash;
7567 the first element of which is the subtraction, and the second element of
7568 which is a bit specifying if the unsigned subtraction resulted in an
7569 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7570
7571<h5>Examples:</h5>
7572<pre>
7573 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7574 %sum = extractvalue {i32, i1} %res, 0
7575 %obit = extractvalue {i32, i1} %res, 1
7576 br i1 %obit, label %overflow, label %normal
7577</pre>
7578
7579</div>
7580
7581<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7582<h4>
7583 <a name="int_smul_overflow">
7584 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7585 </a>
7586</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7587
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7588<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7589
7590<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7591<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7592 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7593
7594<pre>
7595 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7596 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7597 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7598</pre>
7599
7600<h5>Overview:</h5>
7601
7602<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7603 a signed multiplication of the two arguments, and indicate whether an
7604 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7605
7606<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7607<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7608 be of integer types of any bit width, but they must have the same bit
7609 width. The second element of the result structure must be of
7610 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7611 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7612
7613<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7614<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7615 a signed multiplication of the two arguments. They return a structure &mdash;
7616 the first element of which is the multiplication, and the second element of
7617 which is a bit specifying if the signed multiplication resulted in an
7618 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7619
7620<h5>Examples:</h5>
7621<pre>
7622 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7623 %sum = extractvalue {i32, i1} %res, 0
7624 %obit = extractvalue {i32, i1} %res, 1
7625 br i1 %obit, label %overflow, label %normal
7626</pre>
7627
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7628</div>
7629
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7630<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7631<h4>
7632 <a name="int_umul_overflow">
7633 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7634 </a>
7635</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7636
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7637<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7638
7639<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7640<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7641 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7642
7643<pre>
7644 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7645 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7646 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7647</pre>
7648
7649<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7650<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7651 a unsigned multiplication of the two arguments, and indicate whether an
7652 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7653
7654<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7655<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7656 be of integer types of any bit width, but they must have the same bit
7657 width. The second element of the result structure must be of
7658 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7659 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7660
7661<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7662<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7663 an unsigned multiplication of the two arguments. They return a structure
7664 &mdash; the first element of which is the multiplication, and the second
7665 element of which is a bit specifying if the unsigned multiplication resulted
7666 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7667
7668<h5>Examples:</h5>
7669<pre>
7670 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7671 %sum = extractvalue {i32, i1} %res, 0
7672 %obit = extractvalue {i32, i1} %res, 1
7673 br i1 %obit, label %overflow, label %normal
7674</pre>
7675
7676</div>
7677
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7678</div>
7679
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7680<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7681<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7682 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7683</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7684
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7685<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7686
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7687<p>Half precision floating point is a storage-only format. This means that it is
7688 a dense encoding (in memory) but does not support computation in the
7689 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7690
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7691<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7692 value as an i16, then convert it to float with <a
7693 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7694 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7695 double etc). To store the value back to memory, it is first converted to
7696 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7697 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7698 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7699
7700<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7701<h4>
7702 <a name="int_convert_to_fp16">
7703 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7704 </a>
7705</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7706
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7707<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7708
7709<h5>Syntax:</h5>
7710<pre>
7711 declare i16 @llvm.convert.to.fp16(f32 %a)
7712</pre>
7713
7714<h5>Overview:</h5>
7715<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7716 a conversion from single precision floating point format to half precision
7717 floating point format.</p>
7718
7719<h5>Arguments:</h5>
7720<p>The intrinsic function contains single argument - the value to be
7721 converted.</p>
7722
7723<h5>Semantics:</h5>
7724<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7725 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7726 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7727 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7728
7729<h5>Examples:</h5>
7730<pre>
7731 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7732 store i16 %res, i16* @x, align 2
7733</pre>
7734
7735</div>
7736
7737<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7738<h4>
7739 <a name="int_convert_from_fp16">
7740 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7741 </a>
7742</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7743
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7744<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7745
7746<h5>Syntax:</h5>
7747<pre>
7748 declare f32 @llvm.convert.from.fp16(i16 %a)
7749</pre>
7750
7751<h5>Overview:</h5>
7752<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7753 a conversion from half precision floating point format to single precision
7754 floating point format.</p>
7755
7756<h5>Arguments:</h5>
7757<p>The intrinsic function contains single argument - the value to be
7758 converted.</p>
7759
7760<h5>Semantics:</h5>
7761<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7762 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7763 precision floating point format. The input half-float value is represented by
7764 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7765
7766<h5>Examples:</h5>
7767<pre>
7768 %a = load i16* @x, align 2
7769 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7770</pre>
7771
7772</div>
7773
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7774</div>
7775
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7776<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7777<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7778 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7779</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7780
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7781<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7782
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7783<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7784 prefix), are described in
7785 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7786 Level Debugging</a> document.</p>
7787
7788</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7789
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7790<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7791<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7792 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7793</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7794
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7795<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7796
7797<p>The LLVM exception handling intrinsics (which all start with
7798 <tt>llvm.eh.</tt> prefix), are described in
7799 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7800 Handling</a> document.</p>
7801
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7802</div>
7803
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7804<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7805<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7806 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7807</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7808
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7809<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7810
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7811<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7812 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7813 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7814 function pointer lacking the nest parameter - the caller does not need to
7815 provide a value for it. Instead, the value to use is stored in advance in a
7816 "trampoline", a block of memory usually allocated on the stack, which also
7817 contains code to splice the nest value into the argument list. This is used
7818 to implement the GCC nested function address extension.</p>
7819
7820<p>For example, if the function is
7821 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7822 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7823 follows:</p>
7824
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7825<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7826 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7827 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7828 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7829 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7830 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7831</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7832
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7833<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7834 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7835
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7836<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7837<h4>
7838 <a name="int_it">
7839 '<tt>llvm.init.trampoline</tt>' Intrinsic
7840 </a>
7841</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7842
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7843<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7844
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7845<h5>Syntax:</h5>
7846<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7847 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7848</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7849
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7850<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7851<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7852 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7853
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7854<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7855<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7856 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7857 sufficiently aligned block of memory; this memory is written to by the
7858 intrinsic. Note that the size and the alignment are target-specific - LLVM
7859 currently provides no portable way of determining them, so a front-end that
7860 generates this intrinsic needs to have some target-specific knowledge.
7861 The <tt>func</tt> argument must hold a function bitcast to
7862 an <tt>i8*</tt>.</p>
7863
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7864<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7865<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7866 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7867 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7868 which can be <a href="#int_trampoline">bitcast (to a new function) and
7869 called</a>. The new function's signature is the same as that of
7870 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7871 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7872 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7873 with the same argument list, but with <tt>nval</tt> used for the missing
7874 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7875 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7876 to the returned function pointer is undefined.</p>
7877</div>
7878
7879<!-- _______________________________________________________________________ -->
7880<h4>
7881 <a name="int_at">
7882 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7883 </a>
7884</h4>
7885
7886<div>
7887
7888<h5>Syntax:</h5>
7889<pre>
7890 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7891</pre>
7892
7893<h5>Overview:</h5>
7894<p>This performs any required machine-specific adjustment to the address of a
7895 trampoline (passed as <tt>tramp</tt>).</p>
7896
7897<h5>Arguments:</h5>
7898<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7899 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7900 </a>.</p>
7901
7902<h5>Semantics:</h5>
7903<p>On some architectures the address of the code to be executed needs to be
7904 different to the address where the trampoline is actually stored. This
7905 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7906 after performing the required machine specific adjustments.
7907 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7908 executed</a>.
7909</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7910
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7911</div>
7912
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7913</div>
7914
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7915<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7916<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7917 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7918</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7919
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7920<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7921
7922<p>This class of intrinsics exists to information about the lifetime of memory
7923 objects and ranges where variables are immutable.</p>
7924
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7925<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7926<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7927 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7928</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7929
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7930<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7931
7932<h5>Syntax:</h5>
7933<pre>
7934 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7935</pre>
7936
7937<h5>Overview:</h5>
7938<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7939 object's lifetime.</p>
7940
7941<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7942<p>The first argument is a constant integer representing the size of the
7943 object, or -1 if it is variable sized. The second argument is a pointer to
7944 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7945
7946<h5>Semantics:</h5>
7947<p>This intrinsic indicates that before this point in the code, the value of the
7948 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]7949 never be used and has an undefined value. A load from the pointer that
7950 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7951 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7952
7953</div>
7954
7955<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7956<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7957 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7958</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7959
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7960<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7961
7962<h5>Syntax:</h5>
7963<pre>
7964 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7965</pre>
7966
7967<h5>Overview:</h5>
7968<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7969 object's lifetime.</p>
7970
7971<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7972<p>The first argument is a constant integer representing the size of the
7973 object, or -1 if it is variable sized. The second argument is a pointer to
7974 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7975
7976<h5>Semantics:</h5>
7977<p>This intrinsic indicates that after this point in the code, the value of the
7978 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7979 never be used and has an undefined value. Any stores into the memory object
7980 following this intrinsic may be removed as dead.
7981
7982</div>
7983
7984<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7985<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7986 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7987</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7988
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7989<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7990
7991<h5>Syntax:</h5>
7992<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]7993 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7994</pre>
7995
7996<h5>Overview:</h5>
7997<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7998 a memory object will not change.</p>
7999
8000<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8001<p>The first argument is a constant integer representing the size of the
8002 object, or -1 if it is variable sized. The second argument is a pointer to
8003 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8004
8005<h5>Semantics:</h5>
8006<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8007 the return value, the referenced memory location is constant and
8008 unchanging.</p>
8009
8010</div>
8011
8012<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8013<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8014 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8015</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8016
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8017<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8018
8019<h5>Syntax:</h5>
8020<pre>
8021 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8022</pre>
8023
8024<h5>Overview:</h5>
8025<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8026 a memory object are mutable.</p>
8027
8028<h5>Arguments:</h5>
8029<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8030 The second argument is a constant integer representing the size of the
8031 object, or -1 if it is variable sized and the third argument is a pointer
8032 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8033
8034<h5>Semantics:</h5>
8035<p>This intrinsic indicates that the memory is mutable again.</p>
8036
8037</div>
8038
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8039</div>
8040
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8041<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8042<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8043 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8044</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8045
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8046<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8047
8048<p>This class of intrinsics is designed to be generic and has no specific
8049 purpose.</p>
8050
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8051<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8052<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8053 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8054</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8055
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8056<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8057
8058<h5>Syntax:</h5>
8059<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8060 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8061</pre>
8062
8063<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8064<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8065
8066<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8067<p>The first argument is a pointer to a value, the second is a pointer to a
8068 global string, the third is a pointer to a global string which is the source
8069 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8070
8071<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8072<p>This intrinsic allows annotation of local variables with arbitrary strings.
8073 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8074 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8075 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8076
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8077</div>
8078
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8079<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8080<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8081 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8082</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8083
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8084<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8085
8086<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8087<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8088 any integer bit width.</p>
8089
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8090<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8091 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8092 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8093 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8094 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8095 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8096</pre>
8097
8098<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8099<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8100
8101<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8102<p>The first argument is an integer value (result of some expression), the
8103 second is a pointer to a global string, the third is a pointer to a global
8104 string which is the source file name, and the last argument is the line
8105 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8106
8107<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8108<p>This intrinsic allows annotations to be put on arbitrary expressions with
8109 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8110 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8111 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8112
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8113</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8114
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8115<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8116<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8117 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8118</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8119
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8120<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8121
8122<h5>Syntax:</h5>
8123<pre>
8124 declare void @llvm.trap()
8125</pre>
8126
8127<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8128<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8129
8130<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8131<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8132
8133<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8134<p>This intrinsics is lowered to the target dependent trap instruction. If the
8135 target does not have a trap instruction, this intrinsic will be lowered to
8136 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8137
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8138</div>
8139
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8140<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8141<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8142 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8143</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8144
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8145<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8146
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8147<h5>Syntax:</h5>
8148<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8149 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8150</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8151
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8152<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8153<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8154 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8155 ensure that it is placed on the stack before local variables.</p>
8156
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8157<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8158<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8159 arguments. The first argument is the value loaded from the stack
8160 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8161 that has enough space to hold the value of the guard.</p>
8162
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8163<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8164<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8165 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8166 stack. This is to ensure that if a local variable on the stack is
8167 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8168 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8169 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8170 function.</p>
8171
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8172</div>
8173
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8174<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8175<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8176 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8177</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8178
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8179<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8180
8181<h5>Syntax:</h5>
8182<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8183 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8184 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8185</pre>
8186
8187<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8188<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8189 the optimizers to determine at compile time whether a) an operation (like
8190 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8191 runtime check for overflow isn't necessary. An object in this context means
8192 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8193
8194<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8195<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8196 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8197 is a boolean 0 or 1. This argument determines whether you want the
8198 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8199 1, variables are not allowed.</p>
8200
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8201<h5>Semantics:</h5>
8202<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8203 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8204 depending on the <tt>type</tt> argument, if the size cannot be determined at
8205 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8206
8207</div>
8208
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8209</div>
8210
8211</div>
8212
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8213<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8214<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8215<address>
8216 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8217 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8218 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8219 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8220
8221 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8222 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8223 Last modified: $Date$
8224</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8225
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8226</body>
8227</html>