Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / 5fd147f97eb5e4935176f539017727ce74889bc9 / . / llvm / docs / LangRef.html
blob: 2329bdb1c8bb36e55414c7d92b1cee9cef4a06c7 [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>
Jakub Staszak5fd147f2011-12-04 20:44:25 +0000[diff] [blame^]291 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
292 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
293 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
294 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]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>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]309 <li><a href="#int_expect">
310 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]323<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]324<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]325
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]326<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]337<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]338<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]339
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]340<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]360
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]361<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]362<h4>
363 <a name="wellformed">Well-Formedness</a>
364</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]365
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]366<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]372
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375</pre>
376
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]383
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]384</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]385
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]386</div>
387
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]391<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]393
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]394<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]439
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]440<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
443
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]444<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]445
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]446<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]447%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448</pre>
449
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]450<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]452<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]453%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
454%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]455%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456</pre>
457
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]458<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
459 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]461<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]463 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]464
465 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]466 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]468 <li>Unnamed temporaries are numbered sequentially</li>
469</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]471<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]472 demonstrating instructions, we will follow an instruction with a comment that
473 defines the type and name of value produced. Comments are shown in italic
474 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]475
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]476</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]477
478<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]479<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]480<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]481<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]482<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]483<h3>
484 <a name="modulestructure">Module Structure</a>
485</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]486
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]487<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]488
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]489<p>LLVM programs are composed of "Module"s, each of which is a translation unit
490 of the input programs. Each module consists of functions, global variables,
491 and symbol table entries. Modules may be combined together with the LLVM
492 linker, which merges function (and global variable) definitions, resolves
493 forward declarations, and merges symbol table entries. Here is an example of
494 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]495
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]496<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]497<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]498<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]499
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]500<i>; External declaration of the puts function</i>&nbsp;
501<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]502
503<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]504define i32 @main() { <i>; i32()* </i>&nbsp;
505 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
506 %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]507
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]508 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
509 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
510 <a href="#i_ret">ret</a> i32 0&nbsp;
511}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]512
513<i>; Named metadata</i>
514!1 = metadata !{i32 41}
515!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]516</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]517
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518<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]519 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]520 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]521 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
522 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]524<p>In general, a module is made up of a list of global values, where both
525 functions and global variables are global values. Global values are
526 represented by a pointer to a memory location (in this case, a pointer to an
527 array of char, and a pointer to a function), and have one of the
528 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]529
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]530</div>
531
532<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]533<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]534 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]535</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]536
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]537<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]538
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]539<p>All Global Variables and Functions have one of the following types of
540 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]541
542<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]544 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
545 by objects in the current module. In particular, linking code into a
546 module with an private global value may cause the private to be renamed as
547 necessary to avoid collisions. Because the symbol is private to the
548 module, all references can be updated. This doesn't show up in any symbol
549 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]550
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]552 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
553 assembler and evaluated by the linker. Unlike normal strong symbols, they
554 are removed by the linker from the final linked image (executable or
555 dynamic library).</dd>
556
557 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
558 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
559 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
560 linker. The symbols are removed by the linker from the final linked image
561 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]562
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]563 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
565 of the object is not taken. For instance, functions that had an inline
566 definition, but the compiler decided not to inline it. Note,
567 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
568 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
569 visibility. The symbols are removed by the linker from the final linked
570 image (executable or dynamic library).</dd>
571
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]572 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]573 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]574 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
575 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]576
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]578 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]579 into the object file corresponding to the LLVM module. They exist to
580 allow inlining and other optimizations to take place given knowledge of
581 the definition of the global, which is known to be somewhere outside the
582 module. Globals with <tt>available_externally</tt> linkage are allowed to
583 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
584 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]585
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]586 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]587 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]588 the same name when linkage occurs. This can be used to implement
589 some forms of inline functions, templates, or other code which must be
590 generated in each translation unit that uses it, but where the body may
591 be overridden with a more definitive definition later. Unreferenced
592 <tt>linkonce</tt> globals are allowed to be discarded. Note that
593 <tt>linkonce</tt> linkage does not actually allow the optimizer to
594 inline the body of this function into callers because it doesn't know if
595 this definition of the function is the definitive definition within the
596 program or whether it will be overridden by a stronger definition.
597 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
598 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]599
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]600 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]601 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
602 <tt>linkonce</tt> linkage, except that unreferenced globals with
603 <tt>weak</tt> linkage may not be discarded. This is used for globals that
604 are declared "weak" in C source code.</dd>
605
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]607 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
608 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
609 global scope.
610 Symbols with "<tt>common</tt>" linkage are merged in the same way as
611 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]613 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]614 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
615 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]616
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]619 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]620 pointer to array type. When two global variables with appending linkage
621 are linked together, the two global arrays are appended together. This is
622 the LLVM, typesafe, equivalent of having the system linker append together
623 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]624
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]625 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]626 <dd>The semantics of this linkage follow the ELF object file model: the symbol
627 is weak until linked, if not linked, the symbol becomes null instead of
628 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]629
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
631 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]632 <dd>Some languages allow differing globals to be merged, such as two functions
633 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]634 that only equivalent globals are ever merged (the "one definition rule"
635 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]636 and <tt>weak_odr</tt> linkage types to indicate that the global will only
637 be merged with equivalent globals. These linkage types are otherwise the
638 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]639
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]641 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]642 visible, meaning that it participates in linkage and can be used to
643 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]644</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]645
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]646<p>The next two types of linkage are targeted for Microsoft Windows platform
647 only. They are designed to support importing (exporting) symbols from (to)
648 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]650<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]651 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]652 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]653 or variable via a global pointer to a pointer that is set up by the DLL
654 exporting the symbol. On Microsoft Windows targets, the pointer name is
655 formed by combining <code>__imp_</code> and the function or variable
656 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]658 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]659 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]660 pointer to a pointer in a DLL, so that it can be referenced with the
661 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
662 name is formed by combining <code>__imp_</code> and the function or
663 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]664</dl>
665
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]666<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
667 another module defined a "<tt>.LC0</tt>" variable and was linked with this
668 one, one of the two would be renamed, preventing a collision. Since
669 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
670 declarations), they are accessible outside of the current module.</p>
671
672<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]673 other than <tt>external</tt>, <tt>dllimport</tt>
674 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]676<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]677 or <tt>weak_odr</tt> linkages.</p>
678
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]679</div>
680
681<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]682<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]683 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]684</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]685
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]686<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]687
688<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]689 and <a href="#i_invoke">invokes</a> can all have an optional calling
690 convention specified for the call. The calling convention of any pair of
691 dynamic caller/callee must match, or the behavior of the program is
692 undefined. The following calling conventions are supported by LLVM, and more
693 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]694
695<dl>
696 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]698 specified) matches the target C calling conventions. This calling
699 convention supports varargs function calls and tolerates some mismatch in
700 the declared prototype and implemented declaration of the function (as
701 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702
703 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]704 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]705 (e.g. by passing things in registers). This calling convention allows the
706 target to use whatever tricks it wants to produce fast code for the
707 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]708 (Application Binary Interface).
709 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]710 when this or the GHC convention is used.</a> This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713
714 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]715 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]716 as possible under the assumption that the call is not commonly executed.
717 As such, these calls often preserve all registers so that the call does
718 not break any live ranges in the caller side. This calling convention
719 does not support varargs and requires the prototype of all callees to
720 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]721
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]722 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
723 <dd>This calling convention has been implemented specifically for use by the
724 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
725 It passes everything in registers, going to extremes to achieve this by
726 disabling callee save registers. This calling convention should not be
727 used lightly but only for specific situations such as an alternative to
728 the <em>register pinning</em> performance technique often used when
729 implementing functional programming languages.At the moment only X86
730 supports this convention and it has the following limitations:
731 <ul>
732 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
733 floating point types are supported.</li>
734 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
735 6 floating point parameters.</li>
736 </ul>
737 This calling convention supports
738 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
739 requires both the caller and callee are using it.
740 </dd>
741
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]742 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]743 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]744 target-specific calling conventions to be used. Target specific calling
745 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]746</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]747
748<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]749 support Pascal conventions or any other well-known target-independent
750 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]751
752</div>
753
754<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]755<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]756 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]757</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]758
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]759<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]760
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]761<p>All Global Variables and Functions have one of the following visibility
762 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]763
764<dl>
765 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]766 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]767 that the declaration is visible to other modules and, in shared libraries,
768 means that the declared entity may be overridden. On Darwin, default
769 visibility means that the declaration is visible to other modules. Default
770 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771
772 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]773 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]774 object if they are in the same shared object. Usually, hidden visibility
775 indicates that the symbol will not be placed into the dynamic symbol
776 table, so no other module (executable or shared library) can reference it
777 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]778
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]779 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]780 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]781 the dynamic symbol table, but that references within the defining module
782 will bind to the local symbol. That is, the symbol cannot be overridden by
783 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]784</dl>
785
786</div>
787
788<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]789<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]790 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]791</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]792
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]793<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]794
795<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]796 it easier to read the IR and make the IR more condensed (particularly when
797 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]799<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800%mytype = type { %mytype*, i32 }
801</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]802
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]804 "<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]805 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]806
807<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]808 and that you can therefore specify multiple names for the same type. This
809 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
810 uses structural typing, the name is not part of the type. When printing out
811 LLVM IR, the printer will pick <em>one name</em> to render all types of a
812 particular shape. This means that if you have code where two different
813 source types end up having the same LLVM type, that the dumper will sometimes
814 print the "wrong" or unexpected type. This is an important design point and
815 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]816
817</div>
818
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]819<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]820<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]821 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]822</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]823
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]824<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]825
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]826<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]827 instead of run-time. Global variables may optionally be initialized, may
828 have an explicit section to be placed in, and may have an optional explicit
829 alignment specified. A variable may be defined as "thread_local", which
830 means that it will not be shared by threads (each thread will have a
831 separated copy of the variable). A variable may be defined as a global
832 "constant," which indicates that the contents of the variable
833 will <b>never</b> be modified (enabling better optimization, allowing the
834 global data to be placed in the read-only section of an executable, etc).
835 Note that variables that need runtime initialization cannot be marked
836 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]837
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]838<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
839 constant, even if the final definition of the global is not. This capability
840 can be used to enable slightly better optimization of the program, but
841 requires the language definition to guarantee that optimizations based on the
842 'constantness' are valid for the translation units that do not include the
843 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]845<p>As SSA values, global variables define pointer values that are in scope
846 (i.e. they dominate) all basic blocks in the program. Global variables
847 always define a pointer to their "content" type because they describe a
848 region of memory, and all memory objects in LLVM are accessed through
849 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]850
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]851<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
852 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]853 like this can be merged with other constants if they have the same
854 initializer. Note that a constant with significant address <em>can</em>
855 be merged with a <tt>unnamed_addr</tt> constant, the result being a
856 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]857
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]858<p>A global variable may be declared to reside in a target-specific numbered
859 address space. For targets that support them, address spaces may affect how
860 optimizations are performed and/or what target instructions are used to
861 access the variable. The default address space is zero. The address space
862 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]863
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]864<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]865 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]866
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]867<p>An explicit alignment may be specified for a global, which must be a power
868 of 2. If not present, or if the alignment is set to zero, the alignment of
869 the global is set by the target to whatever it feels convenient. If an
870 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]871 alignment. Targets and optimizers are not allowed to over-align the global
872 if the global has an assigned section. In this case, the extra alignment
873 could be observable: for example, code could assume that the globals are
874 densely packed in their section and try to iterate over them as an array,
875 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]876
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]877<p>For example, the following defines a global in a numbered address space with
878 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]879
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]880<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]881@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]882</pre>
883
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]884</div>
885
886
887<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]888<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]889 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]890</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]891
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]892<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]893
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]894<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]895 optional <a href="#linkage">linkage type</a>, an optional
896 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>,
898 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#paramattrs">parameter attribute</a> for the return type, a function
900 name, a (possibly empty) argument list (each with optional
901 <a href="#paramattrs">parameter attributes</a>), optional
902 <a href="#fnattrs">function attributes</a>, an optional section, an optional
903 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
904 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]905
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]906<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
907 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]908 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]909 <a href="#callingconv">calling convention</a>,
910 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]911 <a href="#paramattrs">parameter attribute</a> for the return type, a function
912 name, a possibly empty list of arguments, an optional alignment, and an
913 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]914
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]915<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]916 (Control Flow Graph) for the function. Each basic block may optionally start
917 with a label (giving the basic block a symbol table entry), contains a list
918 of instructions, and ends with a <a href="#terminators">terminator</a>
919 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]920
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]921<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]922 executed on entrance to the function, and it is not allowed to have
923 predecessor basic blocks (i.e. there can not be any branches to the entry
924 block of a function). Because the block can have no predecessors, it also
925 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]927<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]928 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]929
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]930<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]931 the alignment is set to zero, the alignment of the function is set by the
932 target to whatever it feels convenient. If an explicit alignment is
933 specified, the function is forced to have at least that much alignment. All
934 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]935
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]936<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]937 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]938
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]939<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]940<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]941define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
943 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
944 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
945 [<a href="#gc">gc</a>] { ... }
946</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]947
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]948</div>
949
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]950<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]951<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]952 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]953</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]954
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]955<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]956
957<p>Aliases act as "second name" for the aliasee value (which can be either
958 function, global variable, another alias or bitcast of global value). Aliases
959 may have an optional <a href="#linkage">linkage type</a>, and an
960 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]961
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]962<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]963<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]964@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]965</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]966
967</div>
968
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]969<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]970<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]971 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]972</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]973
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]974<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]975
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]976<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]977 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]978 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]979
980<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]981<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]982; Some unnamed metadata nodes, which are referenced by the named metadata.
983!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]984!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]985!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]986; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]987!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]988</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]989
990</div>
991
992<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]993<h3>
994 <a name="paramattrs">Parameter Attributes</a>
995</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]996
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]997<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]998
999<p>The return type and each parameter of a function type may have a set of
1000 <i>parameter attributes</i> associated with them. Parameter attributes are
1001 used to communicate additional information about the result or parameters of
1002 a function. Parameter attributes are considered to be part of the function,
1003 not of the function type, so functions with different parameter attributes
1004 can have the same function type.</p>
1005
1006<p>Parameter attributes are simple keywords that follow the type specified. If
1007 multiple parameter attributes are needed, they are space separated. For
1008 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1009
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1010<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1011declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1012declare i32 @atoi(i8 zeroext)
1013declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1014</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1015
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1016<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1017 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1021<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1022 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1023 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1024 should be zero-extended to the extent required by the target's ABI (which
1025 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1026 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1030 should be sign-extended to the extent required by the target's ABI (which
1031 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1032 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1033
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1034 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1035 <dd>This indicates that this parameter or return value should be treated in a
1036 special target-dependent fashion during while emitting code for a function
1037 call or return (usually, by putting it in a register as opposed to memory,
1038 though some targets use it to distinguish between two different kinds of
1039 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1040
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1041 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1042 <dd><p>This indicates that the pointer parameter should really be passed by
1043 value to the function. The attribute implies that a hidden copy of the
1044 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1045 is made between the caller and the callee, so the callee is unable to
1046 modify the value in the callee. This attribute is only valid on LLVM
1047 pointer arguments. It is generally used to pass structs and arrays by
1048 value, but is also valid on pointers to scalars. The copy is considered
1049 to belong to the caller not the callee (for example,
1050 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1051 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1052 values.</p>
1053
1054 <p>The byval attribute also supports specifying an alignment with
1055 the align attribute. It indicates the alignment of the stack slot to
1056 form and the known alignment of the pointer specified to the call site. If
1057 the alignment is not specified, then the code generator makes a
1058 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1059
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1060 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This indicates that the pointer parameter specifies the address of a
1062 structure that is the return value of the function in the source program.
1063 This pointer must be guaranteed by the caller to be valid: loads and
1064 stores to the structure may be assumed by the callee to not to trap. This
1065 may only be applied to the first parameter. This is not a valid attribute
1066 for return values. </dd>
1067
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1069 <dd>This indicates that pointer values
1070 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1071 value do not alias pointer values which are not <i>based</i> on it,
1072 ignoring certain "irrelevant" dependencies.
1073 For a call to the parent function, dependencies between memory
1074 references from before or after the call and from those during the call
1075 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1076 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1077 The caller shares the responsibility with the callee for ensuring that
1078 these requirements are met.
1079 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1080 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1081<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1082 Note that this definition of <tt>noalias</tt> is intentionally
1083 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1084 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1085<br>
1086 For function return values, C99's <tt>restrict</tt> is not meaningful,
1087 while LLVM's <tt>noalias</tt> is.
1088 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1089
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1090 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1091 <dd>This indicates that the callee does not make any copies of the pointer
1092 that outlive the callee itself. This is not a valid attribute for return
1093 values.</dd>
1094
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1095 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1096 <dd>This indicates that the pointer parameter can be excised using the
1097 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1098 attribute for return values.</dd>
1099</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1100
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1101</div>
1102
1103<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1104<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1105 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1106</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1107
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1108<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1109
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1110<p>Each function may specify a garbage collector name, which is simply a
1111 string:</p>
1112
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1113<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1114define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1115</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1116
1117<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1118 collector which will cause the compiler to alter its output in order to
1119 support the named garbage collection algorithm.</p>
1120
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1121</div>
1122
1123<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1124<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1125 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1126</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1127
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1128<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1129
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1130<p>Function attributes are set to communicate additional information about a
1131 function. Function attributes are considered to be part of the function, not
1132 of the function type, so functions with different parameter attributes can
1133 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1134
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1135<p>Function attributes are simple keywords that follow the type specified. If
1136 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1137
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1138<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1139define void @f() noinline { ... }
1140define void @f() alwaysinline { ... }
1141define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1142define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1143</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1144
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1145<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1146 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1147 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1148 the backend should forcibly align the stack pointer. Specify the
1149 desired alignment, which must be a power of two, in parentheses.
1150
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1151 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1152 <dd>This attribute indicates that the inliner should attempt to inline this
1153 function into callers whenever possible, ignoring any active inlining size
1154 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1155
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1156 <dt><tt><b>nonlazybind</b></tt></dt>
1157 <dd>This attribute suppresses lazy symbol binding for the function. This
1158 may make calls to the function faster, at the cost of extra program
1159 startup time if the function is not called during program startup.</dd>
1160
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1161 <dt><tt><b>inlinehint</b></tt></dt>
1162 <dd>This attribute indicates that the source code contained a hint that inlining
1163 this function is desirable (such as the "inline" keyword in C/C++). It
1164 is just a hint; it imposes no requirements on the inliner.</dd>
1165
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1166 <dt><tt><b>naked</b></tt></dt>
1167 <dd>This attribute disables prologue / epilogue emission for the function.
1168 This can have very system-specific consequences.</dd>
1169
1170 <dt><tt><b>noimplicitfloat</b></tt></dt>
1171 <dd>This attributes disables implicit floating point instructions.</dd>
1172
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1173 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1174 <dd>This attribute indicates that the inliner should never inline this
1175 function in any situation. This attribute may not be used together with
1176 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1177
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1178 <dt><tt><b>noredzone</b></tt></dt>
1179 <dd>This attribute indicates that the code generator should not use a red
1180 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1181
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This function attribute indicates that the function never returns
1184 normally. This produces undefined behavior at runtime if the function
1185 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1186
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1187 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1188 <dd>This function attribute indicates that the function never returns with an
1189 unwind or exceptional control flow. If the function does unwind, its
1190 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1191
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1192 <dt><tt><b>optsize</b></tt></dt>
1193 <dd>This attribute suggests that optimization passes and code generator passes
1194 make choices that keep the code size of this function low, and otherwise
1195 do optimizations specifically to reduce code size.</dd>
1196
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This attribute indicates that the function computes its result (or decides
1199 to unwind an exception) based strictly on its arguments, without
1200 dereferencing any pointer arguments or otherwise accessing any mutable
1201 state (e.g. memory, control registers, etc) visible to caller functions.
1202 It does not write through any pointer arguments
1203 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1204 changes any state visible to callers. This means that it cannot unwind
1205 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1206 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1207
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute indicates that the function does not write through any
1210 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1211 arguments) or otherwise modify any state (e.g. memory, control registers,
1212 etc) visible to caller functions. It may dereference pointer arguments
1213 and read state that may be set in the caller. A readonly function always
1214 returns the same value (or unwinds an exception identically) when called
1215 with the same set of arguments and global state. It cannot unwind an
1216 exception by calling the <tt>C++</tt> exception throwing methods, but may
1217 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1218
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1219 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1220 <dd>This attribute indicates that the function should emit a stack smashing
1221 protector. It is in the form of a "canary"&mdash;a random value placed on
1222 the stack before the local variables that's checked upon return from the
1223 function to see if it has been overwritten. A heuristic is used to
1224 determine if a function needs stack protectors or not.<br>
1225<br>
1226 If a function that has an <tt>ssp</tt> attribute is inlined into a
1227 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1228 function will have an <tt>ssp</tt> attribute.</dd>
1229
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1230 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1231 <dd>This attribute indicates that the function should <em>always</em> emit a
1232 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1233 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1234<br>
1235 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1236 function that doesn't have an <tt>sspreq</tt> attribute or which has
1237 an <tt>ssp</tt> attribute, then the resulting function will have
1238 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1239
1240 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1241 <dd>This attribute indicates that the ABI being targeted requires that
1242 an unwind table entry be produce for this function even if we can
1243 show that no exceptions passes by it. This is normally the case for
1244 the ELF x86-64 abi, but it can be disabled for some compilation
1245 units.</dd>
1246
Rafael Espindolacc349c82011-10-03 14:45:37 +0000[diff] [blame]1247 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1248 <dd>This attribute indicates that this function can return
1249 twice. The C <code>setjmp</code> is an example of such a function.
1250 The compiler disables some optimizations (like tail calls) in the caller of
1251 these functions.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1252</dl>
1253
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1254</div>
1255
1256<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1257<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1258 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1259</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1260
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1261<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1262
1263<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1264 the GCC "file scope inline asm" blocks. These blocks are internally
1265 concatenated by LLVM and treated as a single unit, but may be separated in
1266 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1267
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1268<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1269module asm "inline asm code goes here"
1270module asm "more can go here"
1271</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1272
1273<p>The strings can contain any character by escaping non-printable characters.
1274 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]1275 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1276
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1277<p>The inline asm code is simply printed to the machine code .s file when
1278 assembly code is generated.</p>
1279
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1280</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1281
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1282<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1283<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1284 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1285</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1287<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1288
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1289<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1290 data is to be laid out in memory. The syntax for the data layout is
1291 simply:</p>
1292
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1293<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1294target datalayout = "<i>layout specification</i>"
1295</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1296
1297<p>The <i>layout specification</i> consists of a list of specifications
1298 separated by the minus sign character ('-'). Each specification starts with
1299 a letter and may include other information after the letter to define some
1300 aspect of the data layout. The specifications accepted are as follows:</p>
1301
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1302<dl>
1303 <dt><tt>E</tt></dt>
1304 <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]1305 bits with the most significance have the lowest address location.</dd>
1306
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1307 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1308 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1309 the bits with the least significance have the lowest address
1310 location.</dd>
1311
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1312 <dt><tt>S<i>size</i></tt></dt>
1313 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1314 of stack variables is limited to the natural stack alignment to avoid
1315 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1316 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1317 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1318
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1320 <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]1321 <i>preferred</i> alignments. All sizes are in bits. Specifying
1322 the <i>pref</i> alignment is optional. If omitted, the
1323 preceding <tt>:</tt> should be omitted too.</dd>
1324
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1325 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1326 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1327 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1328
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1329 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1330 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1331 <i>size</i>.</dd>
1332
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1333 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1334 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1335 <i>size</i>. Only values of <i>size</i> that are supported by the target
1336 will work. 32 (float) and 64 (double) are supported on all targets;
1337 80 or 128 (different flavors of long double) are also supported on some
1338 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1339
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1340 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1341 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1342 <i>size</i>.</dd>
1343
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1344 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1345 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1346 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1347
1348 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1349 <dd>This specifies a set of native integer widths for the target CPU
1350 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1351 "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]1352 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1353 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1354</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1355
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1356<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1357 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1358 specifications in the <tt>datalayout</tt> keyword. The default specifications
1359 are given in this list:</p>
1360
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1361<ul>
1362 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1363 <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]1364 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1365 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1366 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1367 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1368 <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]1369 alignment of 64-bits</li>
1370 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1371 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1372 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1373 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1374 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1375 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1376</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1377
1378<p>When LLVM is determining the alignment for a given type, it uses the
1379 following rules:</p>
1380
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1381<ol>
1382 <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]1383 specification is used.</li>
1384
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1385 <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]1386 smallest integer type that is larger than the bitwidth of the sought type
1387 is used. If none of the specifications are larger than the bitwidth then
1388 the the largest integer type is used. For example, given the default
1389 specifications above, the i7 type will use the alignment of i8 (next
1390 largest) while both i65 and i256 will use the alignment of i64 (largest
1391 specified).</li>
1392
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1393 <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]1394 largest vector type that is smaller than the sought vector type will be
1395 used as a fall back. This happens because &lt;128 x double&gt; can be
1396 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1397</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1398
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1399<p>The function of the data layout string may not be what you expect. Notably,
1400 this is not a specification from the frontend of what alignment the code
1401 generator should use.</p>
1402
1403<p>Instead, if specified, the target data layout is required to match what the
1404 ultimate <em>code generator</em> expects. This string is used by the
1405 mid-level optimizers to
1406 improve code, and this only works if it matches what the ultimate code
1407 generator uses. If you would like to generate IR that does not embed this
1408 target-specific detail into the IR, then you don't have to specify the
1409 string. This will disable some optimizations that require precise layout
1410 information, but this also prevents those optimizations from introducing
1411 target specificity into the IR.</p>
1412
1413
1414
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1415</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1416
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1417<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1418<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1419 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1420</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1421
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1422<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1423
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1424<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1425with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1426is undefined. Pointer values are associated with address ranges
1427according to the following rules:</p>
1428
1429<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1430 <li>A pointer value is associated with the addresses associated with
1431 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1432 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1433 range of the variable's storage.</li>
1434 <li>The result value of an allocation instruction is associated with
1435 the address range of the allocated storage.</li>
1436 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1437 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1438 <li>An integer constant other than zero or a pointer value returned
1439 from a function not defined within LLVM may be associated with address
1440 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1441 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1442 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1443</ul>
1444
1445<p>A pointer value is <i>based</i> on another pointer value according
1446 to the following rules:</p>
1447
1448<ul>
1449 <li>A pointer value formed from a
1450 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1451 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1452 <li>The result value of a
1453 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1454 of the <tt>bitcast</tt>.</li>
1455 <li>A pointer value formed by an
1456 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1457 pointer values that contribute (directly or indirectly) to the
1458 computation of the pointer's value.</li>
1459 <li>The "<i>based</i> on" relationship is transitive.</li>
1460</ul>
1461
1462<p>Note that this definition of <i>"based"</i> is intentionally
1463 similar to the definition of <i>"based"</i> in C99, though it is
1464 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1465
1466<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1467<tt><a href="#i_load">load</a></tt> merely indicates the size and
1468alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1469interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1470<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1471and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1472
1473<p>Consequently, type-based alias analysis, aka TBAA, aka
1474<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1475LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1476additional information which specialized optimization passes may use
1477to implement type-based alias analysis.</p>
1478
1479</div>
1480
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1481<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1482<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1483 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1484</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1485
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1486<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1487
1488<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1489href="#i_store"><tt>store</tt></a>s, and <a
1490href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1491The optimizers must not change the number of volatile operations or change their
1492order of execution relative to other volatile operations. The optimizers
1493<i>may</i> change the order of volatile operations relative to non-volatile
1494operations. This is not Java's "volatile" and has no cross-thread
1495synchronization behavior.</p>
1496
1497</div>
1498
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1499<!-- ======================================================================= -->
1500<h3>
1501 <a name="memmodel">Memory Model for Concurrent Operations</a>
1502</h3>
1503
1504<div>
1505
1506<p>The LLVM IR does not define any way to start parallel threads of execution
1507or to register signal handlers. Nonetheless, there are platform-specific
1508ways to create them, and we define LLVM IR's behavior in their presence. This
1509model is inspired by the C++0x memory model.</p>
1510
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1511<p>For a more informal introduction to this model, see the
1512<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1513
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1514<p>We define a <i>happens-before</i> partial order as the least partial order
1515that</p>
1516<ul>
1517 <li>Is a superset of single-thread program order, and</li>
1518 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1519 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1520 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1521 creation, thread joining, etc., and by atomic instructions.
1522 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1523 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1524</ul>
1525
1526<p>Note that program order does not introduce <i>happens-before</i> edges
1527between a thread and signals executing inside that thread.</p>
1528
1529<p>Every (defined) read operation (load instructions, memcpy, atomic
1530loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1531(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1532stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1533initialized globals are considered to have a write of the initializer which is
1534atomic and happens before any other read or write of the memory in question.
1535For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1536any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1537
1538<ul>
1539 <li>If <var>write<sub>1</sub></var> happens before
1540 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1541 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1542 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1543 <li>If <var>R<sub>byte</sub></var> happens before
1544 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1545 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1546</ul>
1547
1548<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1549<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1550 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1551 is supposed to give guarantees which can support
1552 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1553 addresses which do not behave like normal memory. It does not generally
1554 provide cross-thread synchronization.)
1555 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1556 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1557 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1558 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1559 <var>R<sub>byte</sub></var> returns the value written by that
1560 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1561 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1562 <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]1563 values written. See the <a href="#ordering">Atomic Memory Ordering
1564 Constraints</a> section for additional constraints on how the choice
1565 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1566 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1567</ul>
1568
1569<p><var>R</var> returns the value composed of the series of bytes it read.
1570This implies that some bytes within the value may be <tt>undef</tt>
1571<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1572defines the semantics of the operation; it doesn't mean that targets will
1573emit more than one instruction to read the series of bytes.</p>
1574
1575<p>Note that in cases where none of the atomic intrinsics are used, this model
1576places only one restriction on IR transformations on top of what is required
1577for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1578otherwise be stored is not allowed in general. (Specifically, in the case
1579where another thread might write to and read from an address, introducing a
1580store can change a load that may see exactly one write into a load that may
1581see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1582
1583<!-- FIXME: This model assumes all targets where concurrency is relevant have
1584a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1585none of the backends currently in the tree fall into this category; however,
1586there might be targets which care. If there are, we want a paragraph
1587like the following:
1588
1589Targets may specify that stores narrower than a certain width are not
1590available; on such a target, for the purposes of this model, treat any
1591non-atomic write with an alignment or width less than the minimum width
1592as if it writes to the relevant surrounding bytes.
1593-->
1594
1595</div>
1596
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1597<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1598<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1599 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1600</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1601
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1602<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1603
1604<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1605<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1606<a href="#i_fence"><code>fence</code></a>,
1607<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1608<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1609that determines which other atomic instructions on the same address they
1610<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1611but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1612check those specs (see spec references in the
1613<a href="Atomic.html#introduction">atomics guide</a>).
1614<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1615treat these orderings somewhat differently since they don't take an address.
1616See that instruction's documentation for details.</p>
1617
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1618<p>For a simpler introduction to the ordering constraints, see the
1619<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1620
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1621<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1622<dt><code>unordered</code></dt>
1623<dd>The set of values that can be read is governed by the happens-before
1624partial order. A value cannot be read unless some operation wrote it.
1625This is intended to provide a guarantee strong enough to model Java's
1626non-volatile shared variables. This ordering cannot be specified for
1627read-modify-write operations; it is not strong enough to make them atomic
1628in any interesting way.</dd>
1629<dt><code>monotonic</code></dt>
1630<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1631total order for modifications by <code>monotonic</code> operations on each
1632address. All modification orders must be compatible with the happens-before
1633order. There is no guarantee that the modification orders can be combined to
1634a global total order for the whole program (and this often will not be
1635possible). The read in an atomic read-modify-write operation
1636(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1637<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1638reads the value in the modification order immediately before the value it
1639writes. If one atomic read happens before another atomic read of the same
1640address, the later read must see the same value or a later value in the
1641address's modification order. This disallows reordering of
1642<code>monotonic</code> (or stronger) operations on the same address. If an
1643address is written <code>monotonic</code>ally by one thread, and other threads
1644<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1645eventually see the write. This corresponds to the C++0x/C1x
1646<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1647<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1648<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1649a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1650operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1651<dt><code>release</code></dt>
1652<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1653writes a value which is subsequently read by an <code>acquire</code> operation,
1654it <i>synchronizes-with</i> that operation. (This isn't a complete
1655description; see the C++0x definition of a release sequence.) This corresponds
1656to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1657<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1658<code>acquire</code> and <code>release</code> operation on its address.
1659This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1660<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1661<dd>In addition to the guarantees of <code>acq_rel</code>
1662(<code>acquire</code> for an operation which only reads, <code>release</code>
1663for an operation which only writes), there is a global total order on all
1664sequentially-consistent operations on all addresses, which is consistent with
1665the <i>happens-before</i> partial order and with the modification orders of
1666all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1667preceding write to the same address in this global order. This corresponds
1668to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1669</dl>
1670
1671<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1672it only <i>synchronizes with</i> or participates in modification and seq_cst
1673total orderings with other operations running in the same thread (for example,
1674in signal handlers).</p>
1675
1676</div>
1677
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1678</div>
1679
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1680<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1681<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1682<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1683
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1684<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1685
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1686<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1687 intermediate representation. Being typed enables a number of optimizations
1688 to be performed on the intermediate representation directly, without having
1689 to do extra analyses on the side before the transformation. A strong type
1690 system makes it easier to read the generated code and enables novel analyses
1691 and transformations that are not feasible to perform on normal three address
1692 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1693
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1694<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1695<h3>
1696 <a name="t_classifications">Type Classifications</a>
1697</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1698
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1699<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1700
1701<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1702
1703<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1704 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1705 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1706 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1707 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1708 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1709 </tr>
1710 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1711 <td><a href="#t_floating">floating point</a></td>
1712 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1713 </tr>
1714 <tr>
1715 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1716 <td><a href="#t_integer">integer</a>,
1717 <a href="#t_floating">floating point</a>,
1718 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1719 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1720 <a href="#t_struct">structure</a>,
1721 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1722 <a href="#t_label">label</a>,
1723 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1724 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1725 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1726 <tr>
1727 <td><a href="#t_primitive">primitive</a></td>
1728 <td><a href="#t_label">label</a>,
1729 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1730 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1732 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1733 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1734 </tr>
1735 <tr>
1736 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1737 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1738 <a href="#t_function">function</a>,
1739 <a href="#t_pointer">pointer</a>,
1740 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1741 <a href="#t_vector">vector</a>,
1742 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1743 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1744 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1745 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1746</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1747
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1748<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1749 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1750 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1751
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1753
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1755<h3>
1756 <a name="t_primitive">Primitive Types</a>
1757</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1758
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1759<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1760
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1761<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1762 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1763
1764<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1765<h4>
1766 <a name="t_integer">Integer Type</a>
1767</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1769<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1770
1771<h5>Overview:</h5>
1772<p>The integer type is a very simple type that simply specifies an arbitrary
1773 bit width for the integer type desired. Any bit width from 1 bit to
1774 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1775
1776<h5>Syntax:</h5>
1777<pre>
1778 iN
1779</pre>
1780
1781<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1782 value.</p>
1783
1784<h5>Examples:</h5>
1785<table class="layout">
1786 <tr class="layout">
1787 <td class="left"><tt>i1</tt></td>
1788 <td class="left">a single-bit integer.</td>
1789 </tr>
1790 <tr class="layout">
1791 <td class="left"><tt>i32</tt></td>
1792 <td class="left">a 32-bit integer.</td>
1793 </tr>
1794 <tr class="layout">
1795 <td class="left"><tt>i1942652</tt></td>
1796 <td class="left">a really big integer of over 1 million bits.</td>
1797 </tr>
1798</table>
1799
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1800</div>
1801
1802<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1803<h4>
1804 <a name="t_floating">Floating Point Types</a>
1805</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1806
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1807<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1808
1809<table>
1810 <tbody>
1811 <tr><th>Type</th><th>Description</th></tr>
1812 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1813 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1814 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1815 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1816 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1817 </tbody>
1818</table>
1819
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1820</div>
1821
1822<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1823<h4>
1824 <a name="t_x86mmx">X86mmx Type</a>
1825</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1826
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1827<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1828
1829<h5>Overview:</h5>
1830<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>
1831
1832<h5>Syntax:</h5>
1833<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1834 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1835</pre>
1836
1837</div>
1838
1839<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1840<h4>
1841 <a name="t_void">Void Type</a>
1842</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1843
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1844<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1845
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1846<h5>Overview:</h5>
1847<p>The void type does not represent any value and has no size.</p>
1848
1849<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1850<pre>
1851 void
1852</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1853
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1854</div>
1855
1856<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1857<h4>
1858 <a name="t_label">Label Type</a>
1859</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1860
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1861<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1862
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1863<h5>Overview:</h5>
1864<p>The label type represents code labels.</p>
1865
1866<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1867<pre>
1868 label
1869</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1870
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1871</div>
1872
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1873<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1874<h4>
1875 <a name="t_metadata">Metadata Type</a>
1876</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1877
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1878<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1879
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1880<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1881<p>The metadata type represents embedded metadata. No derived types may be
1882 created from metadata except for <a href="#t_function">function</a>
1883 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1884
1885<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1886<pre>
1887 metadata
1888</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1889
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1890</div>
1891
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1892</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1893
1894<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1895<h3>
1896 <a name="t_derived">Derived Types</a>
1897</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1898
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1899<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1900
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1901<p>The real power in LLVM comes from the derived types in the system. This is
1902 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1903 useful types. Each of these types contain one or more element types which
1904 may be a primitive type, or another derived type. For example, it is
1905 possible to have a two dimensional array, using an array as the element type
1906 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1907
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1908<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1909<h4>
1910 <a name="t_aggregate">Aggregate Types</a>
1911</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1912
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1913<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1914
1915<p>Aggregate Types are a subset of derived types that can contain multiple
1916 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1917 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1918 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1919
1920</div>
1921
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1922<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1923<h4>
1924 <a name="t_array">Array Type</a>
1925</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1926
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1927<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1929<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1930<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1931 sequentially in memory. The array type requires a size (number of elements)
1932 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1933
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1934<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1935<pre>
1936 [&lt;# elements&gt; x &lt;elementtype&gt;]
1937</pre>
1938
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1939<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1940 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1941
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1942<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1943<table class="layout">
1944 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1945 <td class="left"><tt>[40 x i32]</tt></td>
1946 <td class="left">Array of 40 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>[41 x i32]</tt></td>
1950 <td class="left">Array of 41 32-bit integer values.</td>
1951 </tr>
1952 <tr class="layout">
1953 <td class="left"><tt>[4 x i8]</tt></td>
1954 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1955 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1956</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1957<p>Here are some examples of multidimensional arrays:</p>
1958<table class="layout">
1959 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1960 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1961 <td class="left">3x4 array of 32-bit integer values.</td>
1962 </tr>
1963 <tr class="layout">
1964 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1965 <td class="left">12x10 array of single precision floating point values.</td>
1966 </tr>
1967 <tr class="layout">
1968 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1969 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1970 </tr>
1971</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1972
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1973<p>There is no restriction on indexing beyond the end of the array implied by
1974 a static type (though there are restrictions on indexing beyond the bounds
1975 of an allocated object in some cases). This means that single-dimension
1976 'variable sized array' addressing can be implemented in LLVM with a zero
1977 length array type. An implementation of 'pascal style arrays' in LLVM could
1978 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1979
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1980</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1981
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1982<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1983<h4>
1984 <a name="t_function">Function Type</a>
1985</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1986
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1987<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1988
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1990<p>The function type can be thought of as a function signature. It consists of
1991 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]1992 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1993
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1995<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1996 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1997</pre>
1998
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1999<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]2000 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2001 which indicates that the function takes a variable number of arguments.
2002 Variable argument functions can access their arguments with
2003 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2004 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2005 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2007<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2008<table class="layout">
2009 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2010 <td class="left"><tt>i32 (i32)</tt></td>
2011 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2012 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2013 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2014 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2015 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2016 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2017 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2018 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2019 </td>
2020 </tr><tr class="layout">
2021 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2022 <td class="left">A vararg function that takes at least one
2023 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2024 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2025 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2026 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2027 </tr><tr class="layout">
2028 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2029 <td class="left">A function taking an <tt>i32</tt>, returning a
2030 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2031 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2032 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2033</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2034
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2035</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2036
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2037<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2038<h4>
2039 <a name="t_struct">Structure Type</a>
2040</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2041
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2042<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2043
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2045<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2046 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]2047
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2048<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2049 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2050 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2051 Structures in registers are accessed using the
2052 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2053 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2054
2055<p>Structures may optionally be "packed" structures, which indicate that the
2056 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2057 the elements. In non-packed structs, padding between field types is inserted
2058 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2059 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2060
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2061<p>Structures can either be "literal" or "identified". A literal structure is
2062 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2063 types are always defined at the top level with a name. Literal types are
2064 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2065 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]2066 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2067</p>
2068
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2070<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2071 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2072 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2073</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2074
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2076<table class="layout">
2077 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2078 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2079 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2080 </tr>
2081 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2082 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2083 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2084 second element is a <a href="#t_pointer">pointer</a> to a
2085 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2086 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2087 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2088 <tr class="layout">
2089 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2090 <td class="left">A packed struct known to be 5 bytes in size.</td>
2091 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2092</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2093
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2094</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2095
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2096<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2097<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2098 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2099</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2100
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2101<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2102
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2103<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2104<p>Opaque structure types are used to represent named structure types that do
2105 not have a body specified. This corresponds (for example) to the C notion of
2106 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2107
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2108<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2109<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2110 %X = type opaque
2111 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2112</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2113
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2114<h5>Examples:</h5>
2115<table class="layout">
2116 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2117 <td class="left"><tt>opaque</tt></td>
2118 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2119 </tr>
2120</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2121
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2122</div>
2123
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2124
2125
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2126<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2127<h4>
2128 <a name="t_pointer">Pointer Type</a>
2129</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2130
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2131<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2132
2133<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2134<p>The pointer type is used to specify memory locations.
2135 Pointers are commonly used to reference objects in memory.</p>
2136
2137<p>Pointer types may have an optional address space attribute defining the
2138 numbered address space where the pointed-to object resides. The default
2139 address space is number zero. The semantics of non-zero address
2140 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2141
2142<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2143 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2144
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2145<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2146<pre>
2147 &lt;type&gt; *
2148</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2149
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2150<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2151<table class="layout">
2152 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2153 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2154 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2155 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2156 </tr>
2157 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2158 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2159 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2160 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2161 <tt>i32</tt>.</td>
2162 </tr>
2163 <tr class="layout">
2164 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2165 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2166 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2167 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2168</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2169
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2170</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2171
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2172<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2173<h4>
2174 <a name="t_vector">Vector Type</a>
2175</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2176
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2177<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2178
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2179<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2180<p>A vector type is a simple derived type that represents a vector of elements.
2181 Vector types are used when multiple primitive data are operated in parallel
2182 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2183 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2184 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2185
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2186<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2187<pre>
2188 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2189</pre>
2190
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2191<p>The number of elements is a constant integer value larger than 0; elementtype
2192 may be any integer or floating point type. Vectors of size zero are not
2193 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2194
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2195<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2196<table class="layout">
2197 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2198 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2199 <td class="left">Vector of 4 32-bit integer values.</td>
2200 </tr>
2201 <tr class="layout">
2202 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2203 <td class="left">Vector of 8 32-bit floating-point values.</td>
2204 </tr>
2205 <tr class="layout">
2206 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2207 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2208 </tr>
2209</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2211</div>
2212
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2213</div>
2214
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2215</div>
2216
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2217<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2218<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2219<!-- *********************************************************************** -->
2220
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2221<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2222
2223<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2224 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2225
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2226<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2227<h3>
2228 <a name="simpleconstants">Simple Constants</a>
2229</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2230
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2231<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2232
2233<dl>
2234 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2235 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2236 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2237
2238 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2239 <dd>Standard integers (such as '4') are constants of
2240 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2241 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2242
2243 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2244 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2245 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2246 notation (see below). The assembler requires the exact decimal value of a
2247 floating-point constant. For example, the assembler accepts 1.25 but
2248 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2249 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2250
2251 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2252 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2253 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2254</dl>
2255
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2256<p>The one non-intuitive notation for constants is the hexadecimal form of
2257 floating point constants. For example, the form '<tt>double
2258 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2259 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2260 constants are required (and the only time that they are generated by the
2261 disassembler) is when a floating point constant must be emitted but it cannot
2262 be represented as a decimal floating point number in a reasonable number of
2263 digits. For example, NaN's, infinities, and other special values are
2264 represented in their IEEE hexadecimal format so that assembly and disassembly
2265 do not cause any bits to change in the constants.</p>
2266
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2267<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2268 represented using the 16-digit form shown above (which matches the IEEE754
2269 representation for double); float values must, however, be exactly
2270 representable as IEE754 single precision. Hexadecimal format is always used
2271 for long double, and there are three forms of long double. The 80-bit format
2272 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2273 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2274 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2275 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2276 currently supported target uses this format. Long doubles will only work if
2277 they match the long double format on your target. All hexadecimal formats
2278 are big-endian (sign bit at the left).</p>
2279
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2280<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2281</div>
2282
2283<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2284<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2285<a name="aggregateconstants"></a> <!-- old anchor -->
2286<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2287</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2288
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2289<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2290
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2291<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2292 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2293
2294<dl>
2295 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2296 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2297 type definitions (a comma separated list of elements, surrounded by braces
2298 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2299 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2300 Structure constants must have <a href="#t_struct">structure type</a>, and
2301 the number and types of elements must match those specified by the
2302 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2303
2304 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2305 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2306 definitions (a comma separated list of elements, surrounded by square
2307 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2308 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2309 the number and types of elements must match those specified by the
2310 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2311
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2312 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2313 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2314 definitions (a comma separated list of elements, surrounded by
2315 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2316 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2317 have <a href="#t_vector">vector type</a>, and the number and types of
2318 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2319
2320 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2321 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2322 value to zero of <em>any</em> type, including scalar and
2323 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2324 This is often used to avoid having to print large zero initializers
2325 (e.g. for large arrays) and is always exactly equivalent to using explicit
2326 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2327
2328 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2329 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2330 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2331 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2332 be interpreted as part of the instruction stream, metadata is a place to
2333 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2334</dl>
2335
2336</div>
2337
2338<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2339<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2340 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2341</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2342
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2343<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2344
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2345<p>The addresses of <a href="#globalvars">global variables</a>
2346 and <a href="#functionstructure">functions</a> are always implicitly valid
2347 (link-time) constants. These constants are explicitly referenced when
2348 the <a href="#identifiers">identifier for the global</a> is used and always
2349 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2350 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2351
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2352<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2353@X = global i32 17
2354@Y = global i32 42
2355@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2356</pre>
2357
2358</div>
2359
2360<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2361<h3>
2362 <a name="undefvalues">Undefined Values</a>
2363</h3>
2364
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2365<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2366
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2367<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]2368 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2369 Undefined values may be of any type (other than '<tt>label</tt>'
2370 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2371
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2372<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2373 program is well defined no matter what value is used. This gives the
2374 compiler more freedom to optimize. Here are some examples of (potentially
2375 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2376
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2377
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2378<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2379 %A = add %X, undef
2380 %B = sub %X, undef
2381 %C = xor %X, undef
2382Safe:
2383 %A = undef
2384 %B = undef
2385 %C = undef
2386</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2387
2388<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]2389 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]2390
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2391<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2392 %A = or %X, undef
2393 %B = and %X, undef
2394Safe:
2395 %A = -1
2396 %B = 0
2397Unsafe:
2398 %A = undef
2399 %B = undef
2400</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2401
2402<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2403 For example, if <tt>%X</tt> has a zero bit, then the output of the
2404 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2405 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2406 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2407 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2408 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2409 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2410 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2411
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2412<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2413 %A = select undef, %X, %Y
2414 %B = select undef, 42, %Y
2415 %C = select %X, %Y, undef
2416Safe:
2417 %A = %X (or %Y)
2418 %B = 42 (or %Y)
2419 %C = %Y
2420Unsafe:
2421 %A = undef
2422 %B = undef
2423 %C = undef
2424</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2425
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2426<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2427 branch) conditions can go <em>either way</em>, but they have to come from one
2428 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2429 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2430 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2431 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2432 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2433 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2434
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2435<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2436 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2437
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2438 %B = undef
2439 %C = xor %B, %B
2440
2441 %D = undef
2442 %E = icmp lt %D, 4
2443 %F = icmp gte %D, 4
2444
2445Safe:
2446 %A = undef
2447 %B = undef
2448 %C = undef
2449 %D = undef
2450 %E = undef
2451 %F = undef
2452</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2453
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2454<p>This example points out that two '<tt>undef</tt>' operands are not
2455 necessarily the same. This can be surprising to people (and also matches C
2456 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2457 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2458 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2459 its value over its "live range". This is true because the variable doesn't
2460 actually <em>have a live range</em>. Instead, the value is logically read
2461 from arbitrary registers that happen to be around when needed, so the value
2462 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2463 need to have the same semantics or the core LLVM "replace all uses with"
2464 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2465
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2466<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2467 %A = fdiv undef, %X
2468 %B = fdiv %X, undef
2469Safe:
2470 %A = undef
2471b: unreachable
2472</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2473
2474<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2475 value</em> and <em>undefined behavior</em>. An undefined value (like
2476 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2477 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2478 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2479 defined on SNaN's. However, in the second example, we can make a more
2480 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2481 arbitrary value, we are allowed to assume that it could be zero. Since a
2482 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2483 the operation does not execute at all. This allows us to delete the divide and
2484 all code after it. Because the undefined operation "can't happen", the
2485 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2486
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2487<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2488a: store undef -> %X
2489b: store %X -> undef
2490Safe:
2491a: &lt;deleted&gt;
2492b: unreachable
2493</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2494
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2495<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2496 undefined value can be assumed to not have any effect; we can assume that the
2497 value is overwritten with bits that happen to match what was already there.
2498 However, a store <em>to</em> an undefined location could clobber arbitrary
2499 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2500
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2501</div>
2502
2503<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2504<h3>
2505 <a name="trapvalues">Trap Values</a>
2506</h3>
2507
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2508<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2509
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2510<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2511 instead of representing an unspecified bit pattern, they represent the
2512 fact that an instruction or constant expression which cannot evoke side
2513 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2514 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2515
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2516<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]2517 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2518 <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]2519
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2520<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2521
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2522<ul>
2523<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2524 their operands.</li>
2525
2526<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2527 to their dynamic predecessor basic block.</li>
2528
2529<li>Function arguments depend on the corresponding actual argument values in
2530 the dynamic callers of their functions.</li>
2531
2532<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2533 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2534 control back to them.</li>
2535
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2536<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2537 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2538 or exception-throwing call instructions that dynamically transfer control
2539 back to them.</li>
2540
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2541<li>Non-volatile loads and stores depend on the most recent stores to all of the
2542 referenced memory addresses, following the order in the IR
2543 (including loads and stores implied by intrinsics such as
2544 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2545
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2546<!-- TODO: In the case of multiple threads, this only applies if the store
2547 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2548
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2549<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2550
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2551<li>An instruction with externally visible side effects depends on the most
2552 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2553 the order in the IR. (This includes
2554 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2555
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2556<li>An instruction <i>control-depends</i> on a
2557 <a href="#terminators">terminator instruction</a>
2558 if the terminator instruction has multiple successors and the instruction
2559 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2560 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2561
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2562<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2563 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2564 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2565 successor.</li>
2566
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2567<li>Dependence is transitive.</li>
2568
2569</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2570
2571<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames91fc0902011-10-13 23:04:49 +0000[diff] [blame]2572 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]2573 operand with a trap value were undef. If they have externally-visible side
2574 effects, the behavior is undefined.</p>
2575
2576<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2577
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2578<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2579entry:
2580 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2581 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2582 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2583 store i32 0, i32* %trap_yet_again ; undefined behavior
2584
2585 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2586 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2587
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2588 store volatile i32 %trap, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2589
2590 %narrowaddr = bitcast i32* @g to i16*
2591 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2592 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2593 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2594
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2595 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2596 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2597
2598true:
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2599 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2600 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2601 br label %end
2602
2603end:
2604 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2605 ; Both edges into this PHI are
2606 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2607 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2608
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2609 store volatile i32 0, i32* @g ; This would depend on the store in %true
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2610 ; if %cmp is true, or the store in %entry
2611 ; otherwise, so this is undefined behavior.
2612
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2613 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2614 ; The same branch again, but this time the
2615 ; true block doesn't have side effects.
2616
2617second_true:
2618 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2619 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2620
2621second_end:
Chris Lattnerbc639292011-11-27 06:56:53 +0000[diff] [blame]2622 store volatile i32 0, i32* @g ; This time, the instruction always depends
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2623 ; on the store in %end. Also, it is
2624 ; control-equivalent to %end, so this is
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2625 ; well-defined (again, ignoring earlier
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2626 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2627</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2628
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2629</div>
2630
2631<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2632<h3>
2633 <a name="blockaddress">Addresses of Basic Blocks</a>
2634</h3>
2635
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2636<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2637
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2638<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2639
2640<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2641 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2642 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2643
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2644<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2645 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2646 comparisons against null. Pointer equality tests between labels addresses
2647 results in undefined behavior &mdash; though, again, comparison against null
2648 is ok, and no label is equal to the null pointer. This may be passed around
2649 as an opaque pointer sized value as long as the bits are not inspected. This
2650 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2651 long as the original value is reconstituted before the <tt>indirectbr</tt>
2652 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2653
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2654<p>Finally, some targets may provide defined semantics when using the value as
2655 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2656
2657</div>
2658
2659
2660<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2661<h3>
2662 <a name="constantexprs">Constant Expressions</a>
2663</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2664
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2665<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2666
2667<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2668 to be used as constants. Constant expressions may be of
2669 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2670 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2671 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2672
2673<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2674 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2675 <dd>Truncate a constant to another type. The bit size of CST must be larger
2676 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2677
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2678 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2679 <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]2680 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2681
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2682 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2683 <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]2684 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2685
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2686 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2687 <dd>Truncate a floating point constant to another floating point type. The
2688 size of CST must be larger than the size of TYPE. Both types must be
2689 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2690
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2691 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2692 <dd>Floating point extend a constant to another type. The size of CST must be
2693 smaller or equal to the size of TYPE. Both types must be floating
2694 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2695
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2696 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2697 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2698 constant. TYPE must be a scalar or vector integer type. CST must be of
2699 scalar or vector floating point type. Both CST and TYPE must be scalars,
2700 or vectors of the same number of elements. If the value won't fit in the
2701 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2702
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2703 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2704 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2705 constant. TYPE must be a scalar or vector integer type. CST must be of
2706 scalar or vector floating point type. Both CST and TYPE must be scalars,
2707 or vectors of the same number of elements. If the value won't fit in the
2708 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2709
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2710 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2711 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2712 constant. TYPE must be a scalar or vector floating point type. CST must be
2713 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2714 vectors of the same number of elements. If the value won't fit in the
2715 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2716
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2717 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2718 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2719 constant. TYPE must be a scalar or vector floating point type. CST must be
2720 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2721 vectors of the same number of elements. If the value won't fit in the
2722 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2723
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2724 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2725 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2726 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2727 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2728 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2729
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2730 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2731 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2732 type. CST must be of integer type. The CST value is zero extended,
2733 truncated, or unchanged to make it fit in a pointer size. This one is
2734 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2735
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2736 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2737 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2738 are the same as those for the <a href="#i_bitcast">bitcast
2739 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2740
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2741 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2742 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2743 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2744 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2745 instruction, the index list may have zero or more indexes, which are
2746 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2747
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2748 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2749 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2750
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2751 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2752 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2753
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2754 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2755 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2756
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2757 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2758 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2759 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2760
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2761 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2762 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2763 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2764
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2765 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2766 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2767 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2768
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2769 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2770 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2771 constants. The index list is interpreted in a similar manner as indices in
2772 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2773 index value must be specified.</dd>
2774
2775 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2776 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2777 constants. The index list is interpreted in a similar manner as indices in
2778 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2779 index value must be specified.</dd>
2780
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2781 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2782 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2783 be any of the <a href="#binaryops">binary</a>
2784 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2785 on operands are the same as those for the corresponding instruction
2786 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2787</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2788
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2789</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2791</div>
2792
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2793<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2794<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2795<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2796<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2797<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2798<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2799<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2800</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2801
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2802<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2803
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2804<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2805 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2806 a special value. This value represents the inline assembler as a string
2807 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2808 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2809 expression has side effects, and a flag indicating whether the function
2810 containing the asm needs to align its stack conservatively. An example
2811 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2812
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2813<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2814i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2815</pre>
2816
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2817<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2818 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2819 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2820
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2821<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2822%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]2823</pre>
2824
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2825<p>Inline asms with side effects not visible in the constraint list must be
2826 marked as having side effects. This is done through the use of the
2827 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2828
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2829<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2830call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2831</pre>
2832
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2833<p>In some cases inline asms will contain code that will not work unless the
2834 stack is aligned in some way, such as calls or SSE instructions on x86,
2835 yet will not contain code that does that alignment within the asm.
2836 The compiler should make conservative assumptions about what the asm might
2837 contain and should generate its usual stack alignment code in the prologue
2838 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2839
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2840<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2841call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2842</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2843
2844<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2845 first.</p>
2846
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2847<!--
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2848<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2849 documented here. Constraints on what can be done (e.g. duplication, moving,
2850 etc need to be documented). This is probably best done by reference to
2851 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2852 -->
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2853
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2854<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2855<h4>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2856 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2857</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2858
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2859<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2860
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2861<p>The call instructions that wrap inline asm nodes may have a
2862 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2863 integers. If present, the code generator will use the integer as the
2864 location cookie value when report errors through the <tt>LLVMContext</tt>
2865 error reporting mechanisms. This allows a front-end to correlate backend
2866 errors that occur with inline asm back to the source code that produced it.
2867 For example:</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2868
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2869<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2870call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2871...
2872!42 = !{ i32 1234567 }
2873</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2874
2875<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]2876 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2877 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]2878
2879</div>
2880
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2881</div>
2882
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2883<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2884<h3>
2885 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2886</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2887
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2888<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2889
2890<p>LLVM IR allows metadata to be attached to instructions in the program that
2891 can convey extra information about the code to the optimizers and code
2892 generator. One example application of metadata is source-level debug
2893 information. There are two metadata primitives: strings and nodes. All
2894 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2895 preceding exclamation point ('<tt>!</tt>').</p>
2896
2897<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2898 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2899 "<tt>xx</tt>" is the two digit hex code. For example:
2900 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2901
2902<p>Metadata nodes are represented with notation similar to structure constants
2903 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2904 exclamation point). Metadata nodes can have any values as their operand. For
2905 example:</p>
2906
2907<div class="doc_code">
2908<pre>
2909!{ metadata !"test\00", i32 10}
2910</pre>
2911</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2912
2913<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2914 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2915 example:</p>
2916
2917<div class="doc_code">
2918<pre>
2919!foo = metadata !{!4, !3}
2920</pre>
2921</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2922
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2923<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2924 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2925
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2926<div class="doc_code">
2927<pre>
2928call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2929</pre>
2930</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2931
2932<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2933 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2934 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2935
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2936<div class="doc_code">
2937<pre>
2938%indvar.next = add i64 %indvar, 1, !dbg !21
2939</pre>
2940</div>
2941
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2942<p>More information about specific metadata nodes recognized by the optimizers
2943 and code generator is found below.</p>
2944
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2945<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2946<h4>
2947 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2948</h4>
2949
2950<div>
2951
2952<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2953 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2954 a type system of a higher level language. This can be used to implement
2955 typical C/C++ TBAA, but it can also be used to implement custom alias
2956 analysis behavior for other languages.</p>
2957
2958<p>The current metadata format is very simple. TBAA metadata nodes have up to
2959 three fields, e.g.:</p>
2960
2961<div class="doc_code">
2962<pre>
2963!0 = metadata !{ metadata !"an example type tree" }
2964!1 = metadata !{ metadata !"int", metadata !0 }
2965!2 = metadata !{ metadata !"float", metadata !0 }
2966!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2967</pre>
2968</div>
2969
2970<p>The first field is an identity field. It can be any value, usually
2971 a metadata string, which uniquely identifies the type. The most important
2972 name in the tree is the name of the root node. Two trees with
2973 different root node names are entirely disjoint, even if they
2974 have leaves with common names.</p>
2975
2976<p>The second field identifies the type's parent node in the tree, or
2977 is null or omitted for a root node. A type is considered to alias
2978 all of its descendants and all of its ancestors in the tree. Also,
2979 a type is considered to alias all types in other trees, so that
2980 bitcode produced from multiple front-ends is handled conservatively.</p>
2981
2982<p>If the third field is present, it's an integer which if equal to 1
2983 indicates that the type is "constant" (meaning
2984 <tt>pointsToConstantMemory</tt> should return true; see
2985 <a href="AliasAnalysis.html#OtherItfs">other useful
2986 <tt>AliasAnalysis</tt> methods</a>).</p>
2987
2988</div>
2989
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2990<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]2991<h4>
2992 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2993</h4>
2994
2995<div>
2996
2997<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
2998 point type. It expresses the maximum relative error of the result of
2999 that instruction, in ULPs. ULP is defined as follows:</p>
3000
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]3001<blockquote>
3002
3003<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3004 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3005 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3006 distance between the two non-equal finite floating-point numbers nearest
3007 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3008
3009</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3010
3011<p>The maximum relative error may be any rational number. The metadata node
3012 shall consist of a pair of unsigned integers respectively representing
3013 the numerator and denominator. For example, 2.5 ULP:</p>
3014
3015<div class="doc_code">
3016<pre>
3017!0 = metadata !{ i32 5, i32 2 }
3018</pre>
3019</div>
3020
3021</div>
3022
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3023</div>
3024
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3025</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3026
3027<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3028<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3029 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3030</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3031<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3032<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3033<p>LLVM has a number of "magic" global variables that contain data that affect
3034code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3035of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3036section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3037by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3038
3039<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3040<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3041<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3042</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3043
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3044<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3045
3046<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3047href="#linkage_appending">appending linkage</a>. This array contains a list of
3048pointers to global variables and functions which may optionally have a pointer
3049cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3050
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3051<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3052<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3053@X = global i8 4
3054@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3055
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3056@llvm.used = appending global [2 x i8*] [
3057 i8* @X,
3058 i8* bitcast (i32* @Y to i8*)
3059], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3060</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3061</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3062
3063<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]3064 compiler, assembler, and linker are required to treat the symbol as if there
3065 is a reference to the global that it cannot see. For example, if a variable
3066 has internal linkage and no references other than that from
3067 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3068 represent references from inline asms and other things the compiler cannot
3069 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3070
3071<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]3072 object file to prevent the assembler and linker from molesting the
3073 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3074
3075</div>
3076
3077<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3078<h3>
3079 <a name="intg_compiler_used">
3080 The '<tt>llvm.compiler.used</tt>' Global Variable
3081 </a>
3082</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3083
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3084<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3085
3086<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3087 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3088 touching the symbol. On targets that support it, this allows an intelligent
3089 linker to optimize references to the symbol without being impeded as it would
3090 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3091
3092<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]3093 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3094
3095</div>
3096
3097<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3098<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3099<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3100</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3101
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3102<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3103
3104<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3105<pre>
3106%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3107@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3108</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3109</div>
3110
3111<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3112 functions and associated priorities. The functions referenced by this array
3113 will be called in ascending order of priority (i.e. lowest first) when the
3114 module is loaded. The order of functions with the same priority is not
3115 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3116
3117</div>
3118
3119<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3120<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3121<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3122</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3123
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3124<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3125
3126<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3127<pre>
3128%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3129@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3130</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3131</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3132
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3133<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3134 and associated priorities. The functions referenced by this array will be
3135 called in descending order of priority (i.e. highest first) when the module
3136 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3137
3138</div>
3139
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3140</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3141
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3142<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3143<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3144<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3145
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3146<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3147
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3148<p>The LLVM instruction set consists of several different classifications of
3149 instructions: <a href="#terminators">terminator
3150 instructions</a>, <a href="#binaryops">binary instructions</a>,
3151 <a href="#bitwiseops">bitwise binary instructions</a>,
3152 <a href="#memoryops">memory instructions</a>, and
3153 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3154
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3155<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3156<h3>
3157 <a name="terminators">Terminator Instructions</a>
3158</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3159
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3160<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3161
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3162<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3163 in a program ends with a "Terminator" instruction, which indicates which
3164 block should be executed after the current block is finished. These
3165 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3166 control flow, not values (the one exception being the
3167 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3168
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3169<p>The terminator instructions are:
3170 '<a href="#i_ret"><tt>ret</tt></a>',
3171 '<a href="#i_br"><tt>br</tt></a>',
3172 '<a href="#i_switch"><tt>switch</tt></a>',
3173 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3174 '<a href="#i_invoke"><tt>invoke</tt></a>',
3175 '<a href="#i_unwind"><tt>unwind</tt></a>',
3176 '<a href="#i_resume"><tt>resume</tt></a>', and
3177 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3178
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3179<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3180<h4>
3181 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3182</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3183
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3184<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3185
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3186<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3187<pre>
3188 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]3189 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3190</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3191
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3192<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3193<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3194 a value) from a function back to the caller.</p>
3195
3196<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3197 value and then causes control flow, and one that just causes control flow to
3198 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3200<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3201<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3202 return value. The type of the return value must be a
3203 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3204
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3205<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3206 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3207 value or a return value with a type that does not match its type, or if it
3208 has a void return type and contains a '<tt>ret</tt>' instruction with a
3209 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3210
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3212<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3213 the calling function's context. If the caller is a
3214 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3215 instruction after the call. If the caller was an
3216 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3217 the beginning of the "normal" destination block. If the instruction returns
3218 a value, that value shall set the call or invoke instruction's return
3219 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3220
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3222<pre>
3223 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3224 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3225 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]3226</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3227
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3228</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3229<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3230<h4>
3231 <a name="i_br">'<tt>br</tt>' Instruction</a>
3232</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3233
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3234<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3236<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3237<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3238 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3239 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3240</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3242<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3243<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3244 different basic block in the current function. There are two forms of this
3245 instruction, corresponding to a conditional branch and an unconditional
3246 branch.</p>
3247
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3248<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3249<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3250 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3251 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3252 target.</p>
3253
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3254<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3255<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3256 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3257 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3258 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3259
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3260<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3261<pre>
3262Test:
3263 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3264 br i1 %cond, label %IfEqual, label %IfUnequal
3265IfEqual:
3266 <a href="#i_ret">ret</a> i32 1
3267IfUnequal:
3268 <a href="#i_ret">ret</a> i32 0
3269</pre>
3270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3271</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3272
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3273<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3274<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3275 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3276</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3277
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3278<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3279
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3280<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3281<pre>
3282 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3283</pre>
3284
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3285<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3286<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]3287 several different places. It is a generalization of the '<tt>br</tt>'
3288 instruction, allowing a branch to occur to one of many possible
3289 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3290
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3291<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3292<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3293 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3294 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3295 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3297<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3298<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3299 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3300 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3301 transferred to the corresponding destination; otherwise, control flow is
3302 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3303
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3304<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3305<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3306 <tt>switch</tt> instruction, this instruction may be code generated in
3307 different ways. For example, it could be generated as a series of chained
3308 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3309
3310<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3311<pre>
3312 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3313 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3314 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3315
3316 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3317 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3318
3319 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3320 switch i32 %val, label %otherwise [ i32 0, label %onzero
3321 i32 1, label %onone
3322 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3323</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3324
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3325</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3326
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3327
3328<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3329<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3330 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3331</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3332
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3333<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3334
3335<h5>Syntax:</h5>
3336<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3337 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]3338</pre>
3339
3340<h5>Overview:</h5>
3341
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3342<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3343 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3344 "<tt>address</tt>". Address must be derived from a <a
3345 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3346
3347<h5>Arguments:</h5>
3348
3349<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3350 rest of the arguments indicate the full set of possible destinations that the
3351 address may point to. Blocks are allowed to occur multiple times in the
3352 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3353
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3354<p>This destination list is required so that dataflow analysis has an accurate
3355 understanding of the CFG.</p>
3356
3357<h5>Semantics:</h5>
3358
3359<p>Control transfers to the block specified in the address argument. All
3360 possible destination blocks must be listed in the label list, otherwise this
3361 instruction has undefined behavior. This implies that jumps to labels
3362 defined in other functions have undefined behavior as well.</p>
3363
3364<h5>Implementation:</h5>
3365
3366<p>This is typically implemented with a jump through a register.</p>
3367
3368<h5>Example:</h5>
3369<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3370 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3371</pre>
3372
3373</div>
3374
3375
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3376<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3377<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3378 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3379</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3380
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3381<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3382
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3383<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3384<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3385 &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]3386 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3387</pre>
3388
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3389<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3390<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3391 function, with the possibility of control flow transfer to either the
3392 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3393 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3394 control flow will return to the "normal" label. If the callee (or any
3395 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3396 instruction, control is interrupted and continued at the dynamically nearest
3397 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3398
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3399<p>The '<tt>exception</tt>' label is a
3400 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3401 exception. As such, '<tt>exception</tt>' label is required to have the
3402 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3403 the information about about the behavior of the program after unwinding
3404 happens, as its first non-PHI instruction. The restrictions on the
3405 "<tt>landingpad</tt>" instruction's tightly couples it to the
3406 "<tt>invoke</tt>" instruction, so that the important information contained
3407 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3408 code motion.</p>
3409
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3411<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3412
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3413<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3414 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3415 convention</a> the call should use. If none is specified, the call
3416 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3417
3418 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3419 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3420 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3421
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3422 <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]3423 function value being invoked. In most cases, this is a direct function
3424 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3425 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3426
3427 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3428 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3429
3430 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3431 signature argument types and parameter attributes. All arguments must be
3432 of <a href="#t_firstclass">first class</a> type. If the function
3433 signature indicates the function accepts a variable number of arguments,
3434 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3435
3436 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3438
3439 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3440 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3441
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3442 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3444 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3445</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3446
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3447<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3448<p>This instruction is designed to operate as a standard
3449 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3450 primary difference is that it establishes an association with a label, which
3451 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3452
3453<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3455 exception. Additionally, this is important for implementation of
3456 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3457
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3458<p>For the purposes of the SSA form, the definition of the value returned by the
3459 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3460 block to the "normal" label. If the callee unwinds then no return value is
3461 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3462
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3463<p>Note that the code generator does not yet completely support unwind, and
3464that the invoke/unwind semantics are likely to change in future versions.</p>
3465
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3466<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3467<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3468 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3469 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3470 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3471 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3472</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3473
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3474</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3475
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3476<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3477
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3478<h4>
3479 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3480</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3481
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3482<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3483
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3484<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3485<pre>
3486 unwind
3487</pre>
3488
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3489<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3490<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491 at the first callee in the dynamic call stack which used
3492 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3493 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3494
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3495<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3496<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3497 immediately halt. The dynamic call stack is then searched for the
3498 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3499 Once found, execution continues at the "exceptional" destination block
3500 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3501 instruction in the dynamic call chain, undefined behavior results.</p>
3502
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3503<p>Note that the code generator does not yet completely support unwind, and
3504that the invoke/unwind semantics are likely to change in future versions.</p>
3505
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3506</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3507
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3508 <!-- _______________________________________________________________________ -->
3509
3510<h4>
3511 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3512</h4>
3513
3514<div>
3515
3516<h5>Syntax:</h5>
3517<pre>
3518 resume &lt;type&gt; &lt;value&gt;
3519</pre>
3520
3521<h5>Overview:</h5>
3522<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3523 successors.</p>
3524
3525<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3526<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3527 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3528 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3529
3530<h5>Semantics:</h5>
3531<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3532 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3533 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3534
3535<h5>Example:</h5>
3536<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3537 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3538</pre>
3539
3540</div>
3541
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3542<!-- _______________________________________________________________________ -->
3543
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3544<h4>
3545 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3546</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3547
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3548<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3549
3550<h5>Syntax:</h5>
3551<pre>
3552 unreachable
3553</pre>
3554
3555<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3556<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557 instruction is used to inform the optimizer that a particular portion of the
3558 code is not reachable. This can be used to indicate that the code after a
3559 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3560
3561<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3562<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3563
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3564</div>
3565
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3566</div>
3567
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3568<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3569<h3>
3570 <a name="binaryops">Binary Operations</a>
3571</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3572
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3573<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3574
3575<p>Binary operators are used to do most of the computation in a program. They
3576 require two operands of the same type, execute an operation on them, and
3577 produce a single value. The operands might represent multiple data, as is
3578 the case with the <a href="#t_vector">vector</a> data type. The result value
3579 has the same type as its operands.</p>
3580
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3581<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3582
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3583<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3584<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3585 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3586</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3587
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3588<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3590<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3591<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3592 &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]3593 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3594 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3595 &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]3596</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3598<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3599<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3600
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3601<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3602<p>The two arguments to the '<tt>add</tt>' instruction must
3603 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3604 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3605
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3606<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3607<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3608
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609<p>If the sum has unsigned overflow, the result returned is the mathematical
3610 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]3611
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3612<p>Because LLVM integers use a two's complement representation, this instruction
3613 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3614
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3615<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3616 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3617 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3618 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3619 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3620
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3621<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3622<pre>
3623 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3624</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3626</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3627
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3628<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3629<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3630 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3631</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3632
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3633<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3634
3635<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3636<pre>
3637 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3638</pre>
3639
3640<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3641<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3642
3643<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3644<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3645 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3646 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3647
3648<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3649<p>The value produced is the floating point sum of the two operands.</p>
3650
3651<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3652<pre>
3653 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3654</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3655
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3656</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3657
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3658<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3659<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3660 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3661</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3662
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3663<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3664
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3665<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3666<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3667 &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]3668 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3669 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3670 &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]3671</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3672
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3673<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3674<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3675 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3676
3677<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678 '<tt>neg</tt>' instruction present in most other intermediate
3679 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3680
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3681<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3682<p>The two arguments to the '<tt>sub</tt>' instruction must
3683 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3684 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3685
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3686<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3687<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3688
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3689<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3690 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3691 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3692
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3693<p>Because LLVM integers use a two's complement representation, this instruction
3694 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3695
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3696<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3697 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3698 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3699 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3700 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3701
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3702<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3703<pre>
3704 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3705 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3706</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3707
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3708</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3709
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3710<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3711<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3712 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3713</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3714
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3715<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3716
3717<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3718<pre>
3719 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3720</pre>
3721
3722<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3723<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3725
3726<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3727 '<tt>fneg</tt>' instruction present in most other intermediate
3728 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3729
3730<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3731<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3732 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3733 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3734
3735<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3736<p>The value produced is the floating point difference of the two operands.</p>
3737
3738<h5>Example:</h5>
3739<pre>
3740 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3741 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3742</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3743
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3744</div>
3745
3746<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3747<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3748 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3749</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3750
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3751<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3752
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3753<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3754<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3755 &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]3756 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3757 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3758 &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]3759</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3760
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3761<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3762<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3764<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3765<p>The two arguments to the '<tt>mul</tt>' instruction must
3766 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3767 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3768
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3769<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3770<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3771
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3772<p>If the result of the multiplication has unsigned overflow, the result
3773 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3774 width of the result.</p>
3775
3776<p>Because LLVM integers use a two's complement representation, and the result
3777 is the same width as the operands, this instruction returns the correct
3778 result for both signed and unsigned integers. If a full product
3779 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3780 be sign-extended or zero-extended as appropriate to the width of the full
3781 product.</p>
3782
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3783<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3784 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3785 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3786 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3787 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3788
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3789<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3790<pre>
3791 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3792</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3793
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3794</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3795
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3796<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3797<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3798 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3799</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3800
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3801<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3802
3803<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3804<pre>
3805 &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]3806</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3808<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3809<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3810
3811<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3812<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3813 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3814 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3815
3816<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3817<p>The value produced is the floating point product of the two operands.</p>
3818
3819<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3820<pre>
3821 &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]3822</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3823
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3824</div>
3825
3826<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3827<h4>
3828 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3829</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3830
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3831<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3832
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3833<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3834<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3835 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3836 &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]3837</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3838
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3839<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3840<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3841
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3842<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3843<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3844 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3845 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3846
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3847<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3848<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3849
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3850<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3851 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3852
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3853<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3854
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3855<p>If the <tt>exact</tt> keyword is present, the result value of the
3856 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3857 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3858
3859
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3860<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3861<pre>
3862 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3863</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3864
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3865</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3866
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3867<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3868<h4>
3869 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3870</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3871
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3872<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3873
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3874<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3875<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3876 &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]3877 &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]3878</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3879
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3880<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3881<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3882
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3883<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3884<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3885 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3886 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3887
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3888<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3889<p>The value produced is the signed integer quotient of the two operands rounded
3890 towards zero.</p>
3891
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3892<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3893 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3894
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3895<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3896 undefined behavior; this is a rare case, but can occur, for example, by doing
3897 a 32-bit division of -2147483648 by -1.</p>
3898
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3899<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3900 <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]3901 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3902
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3903<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3904<pre>
3905 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3906</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3907
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3908</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3909
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3910<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3911<h4>
3912 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3913</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3914
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3915<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3918<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3919 &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]3920</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3921
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3922<h5>Overview:</h5>
3923<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3924
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3925<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3926<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3927 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3928 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3929
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3930<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3931<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3932
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3933<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3934<pre>
3935 &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]3936</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3937
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3938</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3939
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3940<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3941<h4>
3942 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3943</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3944
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3945<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3947<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3948<pre>
3949 &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]3950</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3952<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3953<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3954 division of its two arguments.</p>
3955
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3956<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3957<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3958 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3959 values. Both arguments must have identical types.</p>
3960
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3961<h5>Semantics:</h5>
3962<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3963 This instruction always performs an unsigned division to get the
3964 remainder.</p>
3965
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3966<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3967 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3968
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3969<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3970
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3971<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3972<pre>
3973 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3974</pre>
3975
3976</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3977
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3978<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3979<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3980 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3981</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3982
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3983<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3984
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3985<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3986<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3987 &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]3988</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3989
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3990<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3991<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3992 division of its two operands. This instruction can also take
3993 <a href="#t_vector">vector</a> versions of the values in which case the
3994 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3995
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3996<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3997<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3998 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3999 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4000
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4001<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4002<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]4003 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4004 <i>modulo</i> operator (where the result is either zero or has the same sign
4005 as the divisor, <tt>op2</tt>) of a value.
4006 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4008 Math Forum</a>. For a table of how this is implemented in various languages,
4009 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4010 Wikipedia: modulo operation</a>.</p>
4011
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4012<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4013 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4014
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4015<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4016 Overflow also leads to undefined behavior; this is a rare case, but can
4017 occur, for example, by taking the remainder of a 32-bit division of
4018 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4019 lets srem be implemented using instructions that return both the result of
4020 the division and the remainder.)</p>
4021
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4022<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4023<pre>
4024 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4025</pre>
4026
4027</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4028
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4029<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4030<h4>
4031 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4032</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4033
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4034<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4035
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4036<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4037<pre>
4038 &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]4039</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4041<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4043 its two operands.</p>
4044
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4045<h5>Arguments:</h5>
4046<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4047 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4048 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4049
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4050<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051<p>This instruction returns the <i>remainder</i> of a division. The remainder
4052 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4053
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4054<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4055<pre>
4056 &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]4057</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4058
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4059</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4060
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4061</div>
4062
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4063<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4064<h3>
4065 <a name="bitwiseops">Bitwise Binary Operations</a>
4066</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4067
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4068<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4069
4070<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4071 program. They are generally very efficient instructions and can commonly be
4072 strength reduced from other instructions. They require two operands of the
4073 same type, execute an operation on them, and produce a single value. The
4074 resulting value is the same type as its operands.</p>
4075
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4076<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4077<h4>
4078 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4079</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4080
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4081<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4082
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4083<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4084<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4085 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4086 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4087 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4088 &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]4089</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4090
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4091<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4092<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4093 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4094
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4095<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4096<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4097 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4098 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4099
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4100<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4101<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4102 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4103 is (statically or dynamically) negative or equal to or larger than the number
4104 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4105 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4106 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4107
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4108<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
4109 <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]4110 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4111 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
4112 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4113 they would if the shift were expressed as a mul instruction with the same
4114 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4115
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4116<h5>Example:</h5>
4117<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4118 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4119 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4120 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4121 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4122 &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]4123</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4125</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4126
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4127<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4128<h4>
4129 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4130</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4131
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4132<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4133
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4134<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4135<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4136 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4137 &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]4138</pre>
4139
4140<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4141<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4142 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4143
4144<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4145<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4146 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4147 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4148
4149<h5>Semantics:</h5>
4150<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4151 significant bits of the result will be filled with zero bits after the shift.
4152 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4153 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4154 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4155 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4156
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4157<p>If the <tt>exact</tt> keyword is present, the result value of the
4158 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4159 shifted out are non-zero.</p>
4160
4161
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4162<h5>Example:</h5>
4163<pre>
4164 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4165 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4166 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4167 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4168 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4169 &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]4170</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4171
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4172</div>
4173
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4174<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4175<h4>
4176 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4177</h4>
4178
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4179<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4180
4181<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4183 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4184 &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]4185</pre>
4186
4187<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4189 operand shifted to the right a specified number of bits with sign
4190 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4191
4192<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4193<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4194 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4195 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4196
4197<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4198<p>This instruction always performs an arithmetic shift right operation, The
4199 most significant bits of the result will be filled with the sign bit
4200 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4201 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4202 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4203 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4204
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4205<p>If the <tt>exact</tt> keyword is present, the result value of the
4206 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4207 shifted out are non-zero.</p>
4208
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4209<h5>Example:</h5>
4210<pre>
4211 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4212 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4213 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4214 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4215 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4216 &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]4217</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4218
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4219</div>
4220
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4221<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4222<h4>
4223 <a name="i_and">'<tt>and</tt>' Instruction</a>
4224</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4225
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4226<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4227
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4228<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4229<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4230 &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]4231</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4234<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4235 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4236
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4237<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4238<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4239 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4240 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4242<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4243<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4244
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4245<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4246 <tbody>
4247 <tr>
4248 <td>In0</td>
4249 <td>In1</td>
4250 <td>Out</td>
4251 </tr>
4252 <tr>
4253 <td>0</td>
4254 <td>0</td>
4255 <td>0</td>
4256 </tr>
4257 <tr>
4258 <td>0</td>
4259 <td>1</td>
4260 <td>0</td>
4261 </tr>
4262 <tr>
4263 <td>1</td>
4264 <td>0</td>
4265 <td>0</td>
4266 </tr>
4267 <tr>
4268 <td>1</td>
4269 <td>1</td>
4270 <td>1</td>
4271 </tr>
4272 </tbody>
4273</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4274
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4275<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4276<pre>
4277 &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]4278 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4279 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4280</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4281</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4282<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4283<h4>
4284 <a name="i_or">'<tt>or</tt>' Instruction</a>
4285</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4287<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4288
4289<h5>Syntax:</h5>
4290<pre>
4291 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4292</pre>
4293
4294<h5>Overview:</h5>
4295<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4296 two operands.</p>
4297
4298<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4299<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4301 values. Both arguments must have identical types.</p>
4302
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4303<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4304<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4306<table border="1" cellspacing="0" cellpadding="4">
4307 <tbody>
4308 <tr>
4309 <td>In0</td>
4310 <td>In1</td>
4311 <td>Out</td>
4312 </tr>
4313 <tr>
4314 <td>0</td>
4315 <td>0</td>
4316 <td>0</td>
4317 </tr>
4318 <tr>
4319 <td>0</td>
4320 <td>1</td>
4321 <td>1</td>
4322 </tr>
4323 <tr>
4324 <td>1</td>
4325 <td>0</td>
4326 <td>1</td>
4327 </tr>
4328 <tr>
4329 <td>1</td>
4330 <td>1</td>
4331 <td>1</td>
4332 </tr>
4333 </tbody>
4334</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4336<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4337<pre>
4338 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4339 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4340 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4341</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4342
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4343</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4344
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4345<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4346<h4>
4347 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4348</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4349
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4350<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4351
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4352<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4353<pre>
4354 &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]4355</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4356
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4357<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4358<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4359 its two operands. The <tt>xor</tt> is used to implement the "one's
4360 complement" operation, which is the "~" operator in C.</p>
4361
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4362<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4363<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4364 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4365 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4366
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4367<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4368<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4369
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4370<table border="1" cellspacing="0" cellpadding="4">
4371 <tbody>
4372 <tr>
4373 <td>In0</td>
4374 <td>In1</td>
4375 <td>Out</td>
4376 </tr>
4377 <tr>
4378 <td>0</td>
4379 <td>0</td>
4380 <td>0</td>
4381 </tr>
4382 <tr>
4383 <td>0</td>
4384 <td>1</td>
4385 <td>1</td>
4386 </tr>
4387 <tr>
4388 <td>1</td>
4389 <td>0</td>
4390 <td>1</td>
4391 </tr>
4392 <tr>
4393 <td>1</td>
4394 <td>1</td>
4395 <td>0</td>
4396 </tr>
4397 </tbody>
4398</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4400<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4401<pre>
4402 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4403 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4404 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4405 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4406</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4407
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4408</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4409
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4410</div>
4411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4412<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4413<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4414 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4415</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4416
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4417<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4418
4419<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4420 target-independent manner. These instructions cover the element-access and
4421 vector-specific operations needed to process vectors effectively. While LLVM
4422 does directly support these vector operations, many sophisticated algorithms
4423 will want to use target-specific intrinsics to take full advantage of a
4424 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4425
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4426<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4427<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4428 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4429</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4430
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4431<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4432
4433<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4434<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4435 &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]4436</pre>
4437
4438<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4439<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4440 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4441
4442
4443<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4445 of <a href="#t_vector">vector</a> type. The second operand is an index
4446 indicating the position from which to extract the element. The index may be
4447 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4448
4449<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4450<p>The result is a scalar of the same type as the element type of
4451 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4452 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4453 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4454
4455<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4456<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4457 &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]4458</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4459
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4460</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4461
4462<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4463<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4464 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4465</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4466
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4467<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4468
4469<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4470<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4471 &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]4472</pre>
4473
4474<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4475<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4476 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4477
4478<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4479<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4480 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4481 whose type must equal the element type of the first operand. The third
4482 operand is an index indicating the position at which to insert the value.
4483 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4484
4485<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4486<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4487 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4488 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4489 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4490
4491<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4492<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4493 &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]4494</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4495
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4496</div>
4497
4498<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4499<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4500 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4501</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4502
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4503<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4504
4505<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4506<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4507 &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]4508</pre>
4509
4510<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4511<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4512 from two input vectors, returning a vector with the same element type as the
4513 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4514
4515<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4516<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4517 with types that match each other. The third argument is a shuffle mask whose
4518 element type is always 'i32'. The result of the instruction is a vector
4519 whose length is the same as the shuffle mask and whose element type is the
4520 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4522<p>The shuffle mask operand is required to be a constant vector with either
4523 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4524
4525<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4526<p>The elements of the two input vectors are numbered from left to right across
4527 both of the vectors. The shuffle mask operand specifies, for each element of
4528 the result vector, which element of the two input vectors the result element
4529 gets. The element selector may be undef (meaning "don't care") and the
4530 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4531
4532<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4533<pre>
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; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4535 &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]4536 &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]4537 &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]4538 &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]4539 &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]4540 &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]4541 &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]4542</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4543
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4544</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4545
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4546</div>
4547
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4548<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4549<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4550 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4551</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4552
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4553<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4554
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4555<p>LLVM supports several instructions for working with
4556 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4557
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4558<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4559<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4560 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4561</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4562
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4563<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4564
4565<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4566<pre>
4567 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4568</pre>
4569
4570<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4571<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4572 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4573
4574<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4575<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4576 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4577 <a href="#t_array">array</a> type. The operands are constant indices to
4578 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4579 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4580 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4581 <ul>
4582 <li>Since the value being indexed is not a pointer, the first index is
4583 omitted and assumed to be zero.</li>
4584 <li>At least one index must be specified.</li>
4585 <li>Not only struct indices but also array indices must be in
4586 bounds.</li>
4587 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4588
4589<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4590<p>The result is the value at the position in the aggregate specified by the
4591 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4592
4593<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4594<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4595 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4596</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4597
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4598</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4599
4600<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4601<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4602 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4603</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4604
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4605<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4606
4607<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4608<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4609 &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]4610</pre>
4611
4612<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4613<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4614 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4615
4616<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4617<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4618 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4619 <a href="#t_array">array</a> type. The second operand is a first-class
4620 value to insert. The following operands are constant indices indicating
4621 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]4622 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4623 value to insert must have the same type as the value identified by the
4624 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4625
4626<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4627<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4628 that of <tt>val</tt> except that the value at the position specified by the
4629 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4630
4631<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4632<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4633 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4634 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4635 %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]4636</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4637
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4638</div>
4639
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4640</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4641
4642<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4643<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4644 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4645</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4646
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4647<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4648
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4649<p>A key design point of an SSA-based representation is how it represents
4650 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4651 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4652 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4653
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4654<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4655<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4656 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4657</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4659<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4660
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4661<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4662<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4663 &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]4664</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4666<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4667<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4668 currently executing function, to be automatically released when this function
4669 returns to its caller. The object is always allocated in the generic address
4670 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4671
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4672<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4673<p>The '<tt>alloca</tt>' instruction
4674 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4675 runtime stack, returning a pointer of the appropriate type to the program.
4676 If "NumElements" is specified, it is the number of elements allocated,
4677 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4678 specified, the value result of the allocation is guaranteed to be aligned to
4679 at least that boundary. If not specified, or if zero, the target can choose
4680 to align the allocation on any convenient boundary compatible with the
4681 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4682
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4683<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4684
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4685<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4686<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4687 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4688 memory is automatically released when the function returns. The
4689 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4690 variables that must have an address available. When the function returns
4691 (either with the <tt><a href="#i_ret">ret</a></tt>
4692 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4693 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4694
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4695<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4696<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4697 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4698 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4699 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4700 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4701</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4702
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4703</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4704
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4705<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4706<h4>
4707 <a name="i_load">'<tt>load</tt>' Instruction</a>
4708</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4709
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4710<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4711
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4712<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4713<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4714 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4715 &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]4716 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4717</pre>
4718
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4719<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4720<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4721
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4722<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4723<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4724 from which to load. The pointer must point to
4725 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4726 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4727 number or order of execution of this <tt>load</tt> with other <a
4728 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4729
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4730<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4731 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4732 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4733 not valid on <code>load</code> instructions. Atomic loads produce <a
4734 href="#memorymodel">defined</a> results when they may see multiple atomic
4735 stores. The type of the pointee must be an integer type whose bit width
4736 is a power of two greater than or equal to eight and less than or equal
4737 to a target-specific size limit. <code>align</code> must be explicitly
4738 specified on atomic loads, and the load has undefined behavior if the
4739 alignment is not set to a value which is at least the size in bytes of
4740 the pointee. <code>!nontemporal</code> does not have any defined semantics
4741 for atomic loads.</p>
4742
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4743<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4744 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]4745 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4746 alignment for the target. It is the responsibility of the code emitter to
4747 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4748 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4749 produce less efficient code. An alignment of 1 is always safe.</p>
4750
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4751<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4752 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4753 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4754 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4755 and code generator that this load is not expected to be reused in the cache.
4756 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4757 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4758
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4759<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4760<p>The location of memory pointed to is loaded. If the value being loaded is of
4761 scalar type then the number of bytes read does not exceed the minimum number
4762 of bytes needed to hold all bits of the type. For example, loading an
4763 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4764 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4765 is undefined if the value was not originally written using a store of the
4766 same type.</p>
4767
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4768<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4769<pre>
4770 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4771 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4772 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4773</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4774
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4775</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4776
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4777<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4778<h4>
4779 <a name="i_store">'<tt>store</tt>' Instruction</a>
4780</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4782<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4784<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4785<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4786 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>
4787 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]4788</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4789
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4790<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4791<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4792
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4793<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4794<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4795 and an address at which to store it. The type of the
4796 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4797 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4798 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4799 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4800 order of execution of this <tt>store</tt> with other <a
4801 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4802
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4803<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4804 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4805 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4806 valid on <code>store</code> instructions. Atomic loads produce <a
4807 href="#memorymodel">defined</a> results when they may see multiple atomic
4808 stores. The type of the pointee must be an integer type whose bit width
4809 is a power of two greater than or equal to eight and less than or equal
4810 to a target-specific size limit. <code>align</code> must be explicitly
4811 specified on atomic stores, and the store has undefined behavior if the
4812 alignment is not set to a value which is at least the size in bytes of
4813 the pointee. <code>!nontemporal</code> does not have any defined semantics
4814 for atomic stores.</p>
4815
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4816<p>The optional constant "align" argument specifies the alignment of the
4817 operation (that is, the alignment of the memory address). A value of 0 or an
4818 omitted "align" argument means that the operation has the preferential
4819 alignment for the target. It is the responsibility of the code emitter to
4820 ensure that the alignment information is correct. Overestimating the
4821 alignment results in an undefined behavior. Underestimating the alignment may
4822 produce less efficient code. An alignment of 1 is always safe.</p>
4823
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4824<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4825 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4826 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4827 instruction tells the optimizer and code generator that this load is
4828 not expected to be reused in the cache. The code generator may
4829 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4830 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4831
4832
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4833<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4834<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4835 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4836 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4837 does not exceed the minimum number of bytes needed to hold all bits of the
4838 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4839 writing a value of a type like <tt>i20</tt> with a size that is not an
4840 integral number of bytes, it is unspecified what happens to the extra bits
4841 that do not belong to the type, but they will typically be overwritten.</p>
4842
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4843<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4844<pre>
4845 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4846 store i32 3, i32* %ptr <i>; yields {void}</i>
4847 %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]4848</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4849
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4850</div>
4851
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4852<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4853<h4>
4854<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4855</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4856
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4857<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4858
4859<h5>Syntax:</h5>
4860<pre>
4861 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4862</pre>
4863
4864<h5>Overview:</h5>
4865<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4866between operations.</p>
4867
4868<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4869href="#ordering">ordering</a> argument which defines what
4870<i>synchronizes-with</i> edges they add. They can only be given
4871<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4872<code>seq_cst</code> orderings.</p>
4873
4874<h5>Semantics:</h5>
4875<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4876semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4877<code>acquire</code> ordering semantics if and only if there exist atomic
4878operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4879<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4880<var>X</var> modifies <var>M</var> (either directly or through some side effect
4881of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4882<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4883<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4884than an explicit <code>fence</code>, one (but not both) of the atomic operations
4885<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4886<code>acquire</code> (resp.) ordering constraint and still
4887<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4888<i>happens-before</i> edge.</p>
4889
4890<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4891having both <code>acquire</code> and <code>release</code> semantics specified
4892above, participates in the global program order of other <code>seq_cst</code>
4893operations and/or fences.</p>
4894
4895<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4896specifies that the fence only synchronizes with other fences in the same
4897thread. (This is useful for interacting with signal handlers.)</p>
4898
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4899<h5>Example:</h5>
4900<pre>
4901 fence acquire <i>; yields {void}</i>
4902 fence singlethread seq_cst <i>; yields {void}</i>
4903</pre>
4904
4905</div>
4906
4907<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4908<h4>
4909<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4910</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4911
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4912<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4913
4914<h5>Syntax:</h5>
4915<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4916 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]4917</pre>
4918
4919<h5>Overview:</h5>
4920<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4921It loads a value in memory and compares it to a given value. If they are
4922equal, it stores a new value into the memory.</p>
4923
4924<h5>Arguments:</h5>
4925<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4926address to operate on, a value to compare to the value currently be at that
4927address, and a new value to place at that address if the compared values are
4928equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4929bit width is a power of two greater than or equal to eight and less than
4930or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4931'<var>&lt;new&gt;</var>' must have the same type, and the type of
4932'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4933<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4934optimizer is not allowed to modify the number or order of execution
4935of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4936operations</a>.</p>
4937
4938<!-- FIXME: Extend allowed types. -->
4939
4940<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4941<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4942
4943<p>The optional "<code>singlethread</code>" argument declares that the
4944<code>cmpxchg</code> is only atomic with respect to code (usually signal
4945handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4946cmpxchg is atomic with respect to all other code in the system.</p>
4947
4948<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4949the size in memory of the operand.
4950
4951<h5>Semantics:</h5>
4952<p>The contents of memory at the location specified by the
4953'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4954'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4955'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4956is returned.
4957
4958<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4959purpose of identifying <a href="#release_sequence">release sequences</a>. A
4960failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4961parameter determined by dropping any <code>release</code> part of the
4962<code>cmpxchg</code>'s ordering.</p>
4963
4964<!--
4965FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4966optimization work on ARM.)
4967
4968FIXME: Is a weaker ordering constraint on failure helpful in practice?
4969-->
4970
4971<h5>Example:</h5>
4972<pre>
4973entry:
4974 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4975 <a href="#i_br">br</a> label %loop
4976
4977loop:
4978 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4979 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4980 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4981 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4982 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4983
4984done:
4985 ...
4986</pre>
4987
4988</div>
4989
4990<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4991<h4>
4992<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4993</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4994
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4995<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4996
4997<h5>Syntax:</h5>
4998<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4999 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]5000</pre>
5001
5002<h5>Overview:</h5>
5003<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5004
5005<h5>Arguments:</h5>
5006<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5007operation to apply, an address whose value to modify, an argument to the
5008operation. The operation must be one of the following keywords:</p>
5009<ul>
5010 <li>xchg</li>
5011 <li>add</li>
5012 <li>sub</li>
5013 <li>and</li>
5014 <li>nand</li>
5015 <li>or</li>
5016 <li>xor</li>
5017 <li>max</li>
5018 <li>min</li>
5019 <li>umax</li>
5020 <li>umin</li>
5021</ul>
5022
5023<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5024bit width is a power of two greater than or equal to eight and less than
5025or equal to a target-specific size limit. The type of the
5026'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5027If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5028optimizer is not allowed to modify the number or order of execution of this
5029<code>atomicrmw</code> with other <a href="#volatile">volatile
5030 operations</a>.</p>
5031
5032<!-- FIXME: Extend allowed types. -->
5033
5034<h5>Semantics:</h5>
5035<p>The contents of memory at the location specified by the
5036'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5037back. The original value at the location is returned. The modification is
5038specified by the <var>operation</var> argument:</p>
5039
5040<ul>
5041 <li>xchg: <code>*ptr = val</code></li>
5042 <li>add: <code>*ptr = *ptr + val</code></li>
5043 <li>sub: <code>*ptr = *ptr - val</code></li>
5044 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5045 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5046 <li>or: <code>*ptr = *ptr | val</code></li>
5047 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5048 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5049 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5050 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5051 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5052</ul>
5053
5054<h5>Example:</h5>
5055<pre>
5056 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5057</pre>
5058
5059</div>
5060
5061<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5062<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5063 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5064</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5065
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5066<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5067
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5068<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5069<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5070 &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]5071 &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]5072</pre>
5073
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5074<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5075<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5076 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5077 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5078
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5079<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5080<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5081 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082 elements of the aggregate object are indexed. The interpretation of each
5083 index is dependent on the type being indexed into. The first index always
5084 indexes the pointer value given as the first argument, the second index
5085 indexes a value of the type pointed to (not necessarily the value directly
5086 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5087 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5088 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5089 can never be pointers, since that would require loading the pointer before
5090 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5091
5092<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]5093 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5094 integer <b>constants</b> are allowed. When indexing into an array, pointer
5095 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]5096 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5097
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5098<p>For example, let's consider a C code fragment and how it gets compiled to
5099 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5100
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5101<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5102struct RT {
5103 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5104 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5105 char C;
5106};
5107struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5108 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5109 double Y;
5110 struct RT Z;
5111};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5112
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5113int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5114 return &amp;s[1].Z.B[5][13];
5115}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5116</pre>
5117
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5118<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5119
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5120<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]5121%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5122%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5123
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5124define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5125entry:
5126 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5127 ret i32* %reg
5128}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5129</pre>
5130
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5131<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5132<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]5133 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5134 }</tt>' type, a structure. The second index indexes into the third element
5135 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5136 i8 }</tt>' type, another structure. The third index indexes into the second
5137 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5138 array. The two dimensions of the array are subscripted into, yielding an
5139 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5140 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5141
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5142<p>Note that it is perfectly legal to index partially through a structure,
5143 returning a pointer to an inner element. Because of this, the LLVM code for
5144 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5145
5146<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5147 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5148 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]5149 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5150 %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]5151 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5152 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5153 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5154 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5155</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5156
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5157<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5158 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5159 base pointer is not an <i>in bounds</i> address of an allocated object,
5160 or if any of the addresses that would be formed by successive addition of
5161 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5162 precise signed arithmetic are not an <i>in bounds</i> address of that
5163 allocated object. The <i>in bounds</i> addresses for an allocated object
5164 are all the addresses that point into the object, plus the address one
5165 byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5166
5167<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]5168 the base address with silently-wrapping two's complement arithmetic. If the
5169 offsets have a different width from the pointer, they are sign-extended or
5170 truncated to the width of the pointer. The result value of the
5171 <tt>getelementptr</tt> may be outside the object pointed to by the base
5172 pointer. The result value may not necessarily be used to access memory
5173 though, even if it happens to point into allocated storage. See the
5174 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5175 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5177<p>The getelementptr instruction is often confusing. For some more insight into
5178 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5179
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5180<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5181<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5182 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5183 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5184 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5185 %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]5186 <i>; yields i8*:eptr</i>
5187 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5188 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5189 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5190</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5191
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5192</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5193
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5194</div>
5195
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5196<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5197<h3>
5198 <a name="convertops">Conversion Operations</a>
5199</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5200
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5201<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5202
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5203<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5204 which all take a single operand and a type. They perform various bit
5205 conversions on the operand.</p>
5206
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5207<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5208<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5209 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5210</h4>
5211
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5212<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5213
5214<h5>Syntax:</h5>
5215<pre>
5216 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5217</pre>
5218
5219<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5220<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5221 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5222
5223<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5224<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5225 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5226 of the same number of integers.
5227 The bit size of the <tt>value</tt> must be larger than
5228 the bit size of the destination type, <tt>ty2</tt>.
5229 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5230
5231<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5232<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5233 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5234 source size must be larger than the destination size, <tt>trunc</tt> cannot
5235 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5236
5237<h5>Example:</h5>
5238<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5239 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5240 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5241 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5242 %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]5243</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5244
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5245</div>
5246
5247<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5248<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5249 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5250</h4>
5251
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5252<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5253
5254<h5>Syntax:</h5>
5255<pre>
5256 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5257</pre>
5258
5259<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5260<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5261 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5262
5263
5264<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5265<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5266 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5267 of the same number of integers.
5268 The bit size of the <tt>value</tt> must be smaller than
5269 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5270 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5271
5272<h5>Semantics:</h5>
5273<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]5274 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5275
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5276<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]5277
5278<h5>Example:</h5>
5279<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5280 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5281 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5282 %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]5283</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5284
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5285</div>
5286
5287<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5288<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5289 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5290</h4>
5291
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5292<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5293
5294<h5>Syntax:</h5>
5295<pre>
5296 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5297</pre>
5298
5299<h5>Overview:</h5>
5300<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5301
5302<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5303<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5304 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5305 of the same number of integers.
5306 The bit size of the <tt>value</tt> must be smaller than
5307 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5308 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5309
5310<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5311<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5312 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5313 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5314
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5315<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]5316
5317<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5318<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5319 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5320 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5321 %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]5322</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5323
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5324</div>
5325
5326<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5327<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5328 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5329</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5330
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5331<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5332
5333<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5334<pre>
5335 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5336</pre>
5337
5338<h5>Overview:</h5>
5339<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5340 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5341
5342<h5>Arguments:</h5>
5343<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5344 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5345 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]5346 <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]5347 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5348
5349<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5350<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5351 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5352 <a href="#t_floating">floating point</a> type. If the value cannot fit
5353 within the destination type, <tt>ty2</tt>, then the results are
5354 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5355
5356<h5>Example:</h5>
5357<pre>
5358 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5359 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5360</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5361
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5362</div>
5363
5364<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5365<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5366 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5367</h4>
5368
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5369<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5370
5371<h5>Syntax:</h5>
5372<pre>
5373 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5374</pre>
5375
5376<h5>Overview:</h5>
5377<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]5378 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5379
5380<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5381<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5382 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5383 a <a href="#t_floating">floating point</a> type to cast it to. The source
5384 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5385
5386<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5387<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5388 <a href="#t_floating">floating point</a> type to a larger
5389 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5390 used to make a <i>no-op cast</i> because it always changes bits. Use
5391 <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]5392
5393<h5>Example:</h5>
5394<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5395 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5396 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5397</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5398
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5399</div>
5400
5401<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5402<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5403 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5404</h4>
5405
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5406<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5407
5408<h5>Syntax:</h5>
5409<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5410 &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]5411</pre>
5412
5413<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5414<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5415 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5416
5417<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5418<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5419 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5420 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5421 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5422 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5423
5424<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5425<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5426 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5427 towards zero) unsigned integer value. If the value cannot fit
5428 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5429
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5430<h5>Example:</h5>
5431<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5432 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5433 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5434 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5435</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5436
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5437</div>
5438
5439<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5440<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5441 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5442</h4>
5443
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5444<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5445
5446<h5>Syntax:</h5>
5447<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5448 &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]5449</pre>
5450
5451<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5452<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5453 <a href="#t_floating">floating point</a> <tt>value</tt> to
5454 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5455
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5456<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5457<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5458 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5459 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5460 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5461 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5462
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5463<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5464<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5465 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5466 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5467 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5468
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5469<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5470<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5471 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5472 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5473 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5474</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5475
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5476</div>
5477
5478<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5479<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5480 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5481</h4>
5482
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5483<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5484
5485<h5>Syntax:</h5>
5486<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5487 &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]5488</pre>
5489
5490<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5491<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5492 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5493
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5494<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5495<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]5496 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5497 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5498 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5499 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5500
5501<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5502<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5503 integer quantity and converts it to the corresponding floating point
5504 value. If the value cannot fit in the floating point value, the results are
5505 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5506
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5507<h5>Example:</h5>
5508<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5509 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5510 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5511</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5512
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5513</div>
5514
5515<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5516<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5517 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5518</h4>
5519
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5520<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5521
5522<h5>Syntax:</h5>
5523<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5524 &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]5525</pre>
5526
5527<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5528<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5529 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5530
5531<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5532<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]5533 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5534 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5535 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5536 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5537
5538<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5539<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5540 quantity and converts it to the corresponding floating point value. If the
5541 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5542
5543<h5>Example:</h5>
5544<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5545 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5546 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5547</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5548
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5549</div>
5550
5551<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5552<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5553 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5554</h4>
5555
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5556<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5557
5558<h5>Syntax:</h5>
5559<pre>
5560 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5561</pre>
5562
5563<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5564<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5565 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5566
5567<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5568<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5569 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5570 <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]5571
5572<h5>Semantics:</h5>
5573<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5574 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5575 truncating or zero extending that value to the size of the integer type. If
5576 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5577 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5578 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5579 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5580
5581<h5>Example:</h5>
5582<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5583 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5584 %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]5585</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5586
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5587</div>
5588
5589<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5590<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5591 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5592</h4>
5593
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5594<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5595
5596<h5>Syntax:</h5>
5597<pre>
5598 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5599</pre>
5600
5601<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5602<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5603 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5604
5605<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5606<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5607 value to cast, and a type to cast it to, which must be a
5608 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5609
5610<h5>Semantics:</h5>
5611<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5612 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5613 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5614 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5615 than the size of a pointer then a zero extension is done. If they are the
5616 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5617
5618<h5>Example:</h5>
5619<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5620 %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]5621 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5622 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5623</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5624
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5625</div>
5626
5627<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5628<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5629 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5630</h4>
5631
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5632<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5633
5634<h5>Syntax:</h5>
5635<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5636 &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]5637</pre>
5638
5639<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5640<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5641 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5642
5643<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5644<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5645 non-aggregate first class value, and a type to cast it to, which must also be
5646 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5647 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5648 identical. If the source type is a pointer, the destination type must also be
5649 a pointer. This instruction supports bitwise conversion of vectors to
5650 integers and to vectors of other types (as long as they have the same
5651 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5652
5653<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5654<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5655 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5656 this conversion. The conversion is done as if the <tt>value</tt> had been
5657 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5658 be converted to other pointer types with this instruction. To convert
5659 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5660 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5661
5662<h5>Example:</h5>
5663<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5664 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5665 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5666 %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]5667</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5668
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5669</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5670
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5671</div>
5672
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5673<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5674<h3>
5675 <a name="otherops">Other Operations</a>
5676</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5677
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5678<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5679
5680<p>The instructions in this category are the "miscellaneous" instructions, which
5681 defy better classification.</p>
5682
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5683<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5684<h4>
5685 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5686</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5687
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5688<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5689
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5690<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5691<pre>
5692 &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]5693</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5694
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5695<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5696<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5697 boolean values based on comparison of its two integer, integer vector, or
5698 pointer operands.</p>
5699
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5700<h5>Arguments:</h5>
5701<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5702 the condition code indicating the kind of comparison to perform. It is not a
5703 value, just a keyword. The possible condition code are:</p>
5704
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5705<ol>
5706 <li><tt>eq</tt>: equal</li>
5707 <li><tt>ne</tt>: not equal </li>
5708 <li><tt>ugt</tt>: unsigned greater than</li>
5709 <li><tt>uge</tt>: unsigned greater or equal</li>
5710 <li><tt>ult</tt>: unsigned less than</li>
5711 <li><tt>ule</tt>: unsigned less or equal</li>
5712 <li><tt>sgt</tt>: signed greater than</li>
5713 <li><tt>sge</tt>: signed greater or equal</li>
5714 <li><tt>slt</tt>: signed less than</li>
5715 <li><tt>sle</tt>: signed less or equal</li>
5716</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5717
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5718<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5719 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5720 typed. They must also be identical types.</p>
5721
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5722<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5723<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5724 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5725 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]5726 result, as follows:</p>
5727
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5728<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5729 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5730 <tt>false</tt> otherwise. No sign interpretation is necessary or
5731 performed.</li>
5732
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5733 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5734 <tt>false</tt> otherwise. No sign interpretation is necessary or
5735 performed.</li>
5736
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5737 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5738 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5739
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5740 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5741 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5742 to <tt>op2</tt>.</li>
5743
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5744 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5745 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5746
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5747 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5748 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5749
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5750 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5751 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5752
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5753 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5754 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5755 to <tt>op2</tt>.</li>
5756
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5757 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5758 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5759
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5760 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761 <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]5762</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5763
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5764<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5765 values are compared as if they were integers.</p>
5766
5767<p>If the operands are integer vectors, then they are compared element by
5768 element. The result is an <tt>i1</tt> vector with the same number of elements
5769 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5770
5771<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5772<pre>
5773 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5774 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5775 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5776 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5777 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5778 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5779</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5780
5781<p>Note that the code generator does not yet support vector types with
5782 the <tt>icmp</tt> instruction.</p>
5783
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5784</div>
5785
5786<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5787<h4>
5788 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5789</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5790
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5791<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5792
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5793<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5794<pre>
5795 &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]5796</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5797
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5798<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5799<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5800 values based on comparison of its operands.</p>
5801
5802<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]5803(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804
5805<p>If the operands are floating point vectors, then the result type is a vector
5806 of boolean with the same number of elements as the operands being
5807 compared.</p>
5808
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5809<h5>Arguments:</h5>
5810<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5811 the condition code indicating the kind of comparison to perform. It is not a
5812 value, just a keyword. The possible condition code are:</p>
5813
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5814<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5815 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5816 <li><tt>oeq</tt>: ordered and equal</li>
5817 <li><tt>ogt</tt>: ordered and greater than </li>
5818 <li><tt>oge</tt>: ordered and greater than or equal</li>
5819 <li><tt>olt</tt>: ordered and less than </li>
5820 <li><tt>ole</tt>: ordered and less than or equal</li>
5821 <li><tt>one</tt>: ordered and not equal</li>
5822 <li><tt>ord</tt>: ordered (no nans)</li>
5823 <li><tt>ueq</tt>: unordered or equal</li>
5824 <li><tt>ugt</tt>: unordered or greater than </li>
5825 <li><tt>uge</tt>: unordered or greater than or equal</li>
5826 <li><tt>ult</tt>: unordered or less than </li>
5827 <li><tt>ule</tt>: unordered or less than or equal</li>
5828 <li><tt>une</tt>: unordered or not equal</li>
5829 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5830 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5831</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5833<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5834 <i>unordered</i> means that either operand may be a QNAN.</p>
5835
5836<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5837 a <a href="#t_floating">floating point</a> type or
5838 a <a href="#t_vector">vector</a> of floating point type. They must have
5839 identical types.</p>
5840
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5841<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5842<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5843 according to the condition code given as <tt>cond</tt>. If the operands are
5844 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5845 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5846 follows:</p>
5847
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5848<ol>
5849 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5851 <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]5852 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5853
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5854 <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]5855 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5856
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5857 <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]5858 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5859
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5860 <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]5861 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5862
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5863 <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]5864 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5865
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5866 <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]5867 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5868
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5869 <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]5870
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5871 <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]5872 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5873
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5874 <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]5875 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5876
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5877 <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]5878 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5879
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5880 <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]5881 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5882
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5883 <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]5884 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5885
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5886 <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]5887 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5888
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5889 <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]5890
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5891 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5892</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5893
5894<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895<pre>
5896 &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]5897 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5898 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5899 &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]5900</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5901
5902<p>Note that the code generator does not yet support vector types with
5903 the <tt>fcmp</tt> instruction.</p>
5904
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5905</div>
5906
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5907<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5908<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5909 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5910</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5911
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5912<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5913
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5914<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5915<pre>
5916 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5917</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5918
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5919<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5920<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5921 SSA graph representing the function.</p>
5922
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5923<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5924<p>The type of the incoming values is specified with the first type field. After
5925 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5926 one pair for each predecessor basic block of the current block. Only values
5927 of <a href="#t_firstclass">first class</a> type may be used as the value
5928 arguments to the PHI node. Only labels may be used as the label
5929 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5930
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5931<p>There must be no non-phi instructions between the start of a basic block and
5932 the PHI instructions: i.e. PHI instructions must be first in a basic
5933 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5934
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5935<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5936 occur on the edge from the corresponding predecessor block to the current
5937 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5938 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5939
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5940<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5941<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5942 specified by the pair corresponding to the predecessor basic block that
5943 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5944
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5945<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5946<pre>
5947Loop: ; Infinite loop that counts from 0 on up...
5948 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5949 %nextindvar = add i32 %indvar, 1
5950 br label %Loop
5951</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5952
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5953</div>
5954
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5956<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5957 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5958</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5959
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5960<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5961
5962<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5963<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5964 &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>
5965
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5966 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5967</pre>
5968
5969<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5970<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5971 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5972
5973
5974<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5975<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5976 values indicating the condition, and two values of the
5977 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5978 vectors and the condition is a scalar, then entire vectors are selected, not
5979 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5980
5981<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5982<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5983 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5984
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5985<p>If the condition is a vector of i1, then the value arguments must be vectors
5986 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5987
5988<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5989<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5990 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5991</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5992
5993<p>Note that the code generator does not yet support conditions
5994 with vector type.</p>
5995
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5996</div>
5997
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5998<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5999<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6000 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6001</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6002
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6003<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6004
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6005<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6006<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6007 &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]6008</pre>
6009
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6010<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6011<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6012
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6013<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6014<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6015
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6016<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6017 <li>The optional "tail" marker indicates that the callee function does not
6018 access any allocas or varargs in the caller. Note that calls may be
6019 marked "tail" even if they do not occur before
6020 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6021 present, the function call is eligible for tail call optimization,
6022 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6023 optimized into a jump</a>. The code generator may optimize calls marked
6024 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6025 sibling call optimization</a> when the caller and callee have
6026 matching signatures, or 2) forced tail call optimization when the
6027 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6028 <ul>
6029 <li>Caller and callee both have the calling
6030 convention <tt>fastcc</tt>.</li>
6031 <li>The call is in tail position (ret immediately follows call and ret
6032 uses value of call or is void).</li>
6033 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6034 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6035 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6036 constraints are met.</a></li>
6037 </ul>
6038 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6039
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6040 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6041 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6042 defaults to using C calling conventions. The calling convention of the
6043 call must match the calling convention of the target function, or else the
6044 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6045
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6046 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6047 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6048 '<tt>inreg</tt>' attributes are valid here.</li>
6049
6050 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6051 type of the return value. Functions that return no value are marked
6052 <tt><a href="#t_void">void</a></tt>.</li>
6053
6054 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6055 being invoked. The argument types must match the types implied by this
6056 signature. This type can be omitted if the function is not varargs and if
6057 the function type does not return a pointer to a function.</li>
6058
6059 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6060 be invoked. In most cases, this is a direct function invocation, but
6061 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6062 to function value.</li>
6063
6064 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6065 signature argument types and parameter attributes. All arguments must be
6066 of <a href="#t_firstclass">first class</a> type. If the function
6067 signature indicates the function accepts a variable number of arguments,
6068 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6069
6070 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6071 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6072 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6073</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6074
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6075<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6076<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6077 a specified function, with its incoming arguments bound to the specified
6078 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6079 function, control flow continues with the instruction after the function
6080 call, and the return value of the function is bound to the result
6081 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6082
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6083<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6084<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6085 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6086 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6087 %X = tail call i32 @foo() <i>; yields i32</i>
6088 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6089 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6090
6091 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6092 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6093 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6094 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6095 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6096 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6097</pre>
6098
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6099<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6100standard C99 library as being the C99 library functions, and may perform
6101optimizations or generate code for them under that assumption. This is
6102something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6103freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6104
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6105</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6106
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6107<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6108<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6109 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6110</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6111
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6112<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6113
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6114<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6115<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6116 &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]6117</pre>
6118
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6119<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6120<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6121 the "variable argument" area of a function call. It is used to implement the
6122 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6123
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6124<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6126 argument. It returns a value of the specified argument type and increments
6127 the <tt>va_list</tt> to point to the next argument. The actual type
6128 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6129
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6130<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6132 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6133 to the next argument. For more information, see the variable argument
6134 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6135
6136<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]6137 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6138 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6139
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6140<p><tt>va_arg</tt> is an LLVM instruction instead of
6141 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6142 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6143
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6144<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6145<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6146
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6147<p>Note that the code generator does not yet fully support va_arg on many
6148 targets. Also, it does not currently support va_arg with aggregate types on
6149 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6150
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6151</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6152
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6153<!-- _______________________________________________________________________ -->
6154<h4>
6155 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6156</h4>
6157
6158<div>
6159
6160<h5>Syntax:</h5>
6161<pre>
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6162 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6163 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6164
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6165 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6166 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6167</pre>
6168
6169<h5>Overview:</h5>
6170<p>The '<tt>landingpad</tt>' instruction is used by
6171 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6172 system</a> to specify that a basic block is a landing pad &mdash; one where
6173 the exception lands, and corresponds to the code found in the
6174 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6175 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6176 re-entry to the function. The <tt>resultval</tt> has the
6177 type <tt>somety</tt>.</p>
6178
6179<h5>Arguments:</h5>
6180<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6181 function associated with the unwinding mechanism. The optional
6182 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6183
6184<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6185 or <tt>filter</tt> &mdash; and contains the global variable representing the
6186 "type" that may be caught or filtered respectively. Unlike the
6187 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6188 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6189 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6190 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6191
6192<h5>Semantics:</h5>
6193<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6194 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6195 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6196 calling conventions, how the personality function results are represented in
6197 LLVM IR is target specific.</p>
6198
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6199<p>The clauses are applied in order from top to bottom. If two
6200 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendlinga503fc02011-08-08 07:58:58 +0000[diff] [blame]6201 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6202
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6203<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6204
6205<ul>
6206 <li>A landing pad block is a basic block which is the unwind destination of an
6207 '<tt>invoke</tt>' instruction.</li>
6208 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6209 first non-PHI instruction.</li>
6210 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6211 pad block.</li>
6212 <li>A basic block that is not a landing pad block may not include a
6213 '<tt>landingpad</tt>' instruction.</li>
6214 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6215 personality function.</li>
6216</ul>
6217
6218<h5>Example:</h5>
6219<pre>
6220 ;; A landing pad which can catch an integer.
6221 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6222 catch i8** @_ZTIi
6223 ;; A landing pad that is a cleanup.
6224 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6225 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6226 ;; A landing pad which can catch an integer and can only throw a double.
6227 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6228 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6229 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6230</pre>
6231
6232</div>
6233
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6234</div>
6235
6236</div>
6237
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6238<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6239<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6240<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6241
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6242<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6243
6244<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6245 well known names and semantics and are required to follow certain
6246 restrictions. Overall, these intrinsics represent an extension mechanism for
6247 the LLVM language that does not require changing all of the transformations
6248 in LLVM when adding to the language (or the bitcode reader/writer, the
6249 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6250
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6251<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6252 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6253 begin with this prefix. Intrinsic functions must always be external
6254 functions: you cannot define the body of intrinsic functions. Intrinsic
6255 functions may only be used in call or invoke instructions: it is illegal to
6256 take the address of an intrinsic function. Additionally, because intrinsic
6257 functions are part of the LLVM language, it is required if any are added that
6258 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6259
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6260<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6261 family of functions that perform the same operation but on different data
6262 types. Because LLVM can represent over 8 million different integer types,
6263 overloading is used commonly to allow an intrinsic function to operate on any
6264 integer type. One or more of the argument types or the result type can be
6265 overloaded to accept any integer type. Argument types may also be defined as
6266 exactly matching a previous argument's type or the result type. This allows
6267 an intrinsic function which accepts multiple arguments, but needs all of them
6268 to be of the same type, to only be overloaded with respect to a single
6269 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6270
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6271<p>Overloaded intrinsics will have the names of its overloaded argument types
6272 encoded into its function name, each preceded by a period. Only those types
6273 which are overloaded result in a name suffix. Arguments whose type is matched
6274 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6275 can take an integer of any width and returns an integer of exactly the same
6276 integer width. This leads to a family of functions such as
6277 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6278 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6279 suffix is required. Because the argument's type is matched against the return
6280 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6281
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6282<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6283 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6284
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6285<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6286<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6287 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6288</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6289
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6290<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6291
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6292<p>Variable argument support is defined in LLVM with
6293 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6294 intrinsic functions. These functions are related to the similarly named
6295 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6296
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6297<p>All of these functions operate on arguments that use a target-specific value
6298 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6299 not define what this type is, so all transformations should be prepared to
6300 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6301
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6302<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]6303 instruction and the variable argument handling intrinsic functions are
6304 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6305
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6306<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6307define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6308 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6309 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6310 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6311 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6312
6313 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6314 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6315
6316 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6317 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6318 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6319 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6320 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6321
6322 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6323 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6324 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6325}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6326
6327declare void @llvm.va_start(i8*)
6328declare void @llvm.va_copy(i8*, i8*)
6329declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6330</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6331
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6332<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6333<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6334 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6335</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6336
6337
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6338<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6340<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6341<pre>
6342 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6343</pre>
6344
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6345<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6346<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6347 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]6348
6349<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6350<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]6351
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6352<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6353<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]6354 macro available in C. In a target-dependent way, it initializes
6355 the <tt>va_list</tt> element to which the argument points, so that the next
6356 call to <tt>va_arg</tt> will produce the first variable argument passed to
6357 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6358 need to know the last argument of the function as the compiler can figure
6359 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6360
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6361</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6362
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6363<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6364<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6365 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6366</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6367
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6368<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6369
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6370<h5>Syntax:</h5>
6371<pre>
6372 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6373</pre>
6374
6375<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6376<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6377 which has been initialized previously
6378 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6379 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6380
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6381<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6382<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]6383
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6384<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6385<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]6386 macro available in C. In a target-dependent way, it destroys
6387 the <tt>va_list</tt> element to which the argument points. Calls
6388 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6389 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6390 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6391
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6392</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6393
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6394<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6395<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6396 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6397</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6398
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6399<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6400
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6401<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6402<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6403 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6404</pre>
6405
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6406<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6407<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6408 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6409
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6410<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6411<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]6412 The second argument is a pointer to a <tt>va_list</tt> element to copy
6413 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6414
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6415<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6416<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]6417 macro available in C. In a target-dependent way, it copies the
6418 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6419 element. This intrinsic is necessary because
6420 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6421 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6422
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6423</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6424
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6425</div>
6426
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6427<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6428<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6429 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6430</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6431
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6432<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6433
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6434<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6435Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6436intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6437roots on the stack</a>, as well as garbage collector implementations that
6438require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6439barriers. Front-ends for type-safe garbage collected languages should generate
6440these intrinsics to make use of the LLVM garbage collectors. For more details,
6441see <a href="GarbageCollection.html">Accurate Garbage Collection with
6442LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6443
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6444<p>The garbage collection intrinsics only operate on objects in the generic
6445 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6446
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6447<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6448<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6449 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6450</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6451
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6452<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6453
6454<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6455<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6456 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6457</pre>
6458
6459<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6460<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]6461 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6462
6463<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6464<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6465 root pointer. The second pointer (which must be either a constant or a
6466 global value address) contains the meta-data to be associated with the
6467 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6468
6469<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6470<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]6471 location. At compile-time, the code generator generates information to allow
6472 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6473 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6474 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6475
6476</div>
6477
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6478<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6479<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6480 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6481</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6482
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6483<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6484
6485<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6486<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6487 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6488</pre>
6489
6490<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6491<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6492 locations, allowing garbage collector implementations that require read
6493 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6494
6495<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6496<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]6497 allocated from the garbage collector. The first object is a pointer to the
6498 start of the referenced object, if needed by the language runtime (otherwise
6499 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6500
6501<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6502<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6503 instruction, but may be replaced with substantially more complex code by the
6504 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6505 may only be used in a function which <a href="#gc">specifies a GC
6506 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6507
6508</div>
6509
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6510<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6511<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6512 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6513</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6514
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6515<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6516
6517<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6518<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6519 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6520</pre>
6521
6522<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6523<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6524 locations, allowing garbage collector implementations that require write
6525 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6526
6527<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6528<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]6529 object to store it to, and the third is the address of the field of Obj to
6530 store to. If the runtime does not require a pointer to the object, Obj may
6531 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6532
6533<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6534<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6535 instruction, but may be replaced with substantially more complex code by the
6536 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6537 may only be used in a function which <a href="#gc">specifies a GC
6538 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6539
6540</div>
6541
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6542</div>
6543
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6544<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6545<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6546 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6547</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6548
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6549<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6550
6551<p>These intrinsics are provided by LLVM to expose special features that may
6552 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6553
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6554<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6555<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6556 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6557</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6558
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6559<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6560
6561<h5>Syntax:</h5>
6562<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6563 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6564</pre>
6565
6566<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6567<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6568 target-specific value indicating the return address of the current function
6569 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6570
6571<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6572<p>The argument to this intrinsic indicates which function to return the address
6573 for. Zero indicates the calling function, one indicates its caller, etc.
6574 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6575
6576<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6577<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6578 indicating the return address of the specified call frame, or zero if it
6579 cannot be identified. The value returned by this intrinsic is likely to be
6580 incorrect or 0 for arguments other than zero, so it should only be used for
6581 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6582
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6583<p>Note that calling this intrinsic does not prevent function inlining or other
6584 aggressive transformations, so the value returned may not be that of the
6585 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6586
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6587</div>
6588
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6589<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6590<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6591 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6592</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6593
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6594<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6595
6596<h5>Syntax:</h5>
6597<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6598 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6599</pre>
6600
6601<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6602<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6603 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6604
6605<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6606<p>The argument to this intrinsic indicates which function to return the frame
6607 pointer for. Zero indicates the calling function, one indicates its caller,
6608 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6609
6610<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6611<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6612 indicating the frame address of the specified call frame, or zero if it
6613 cannot be identified. The value returned by this intrinsic is likely to be
6614 incorrect or 0 for arguments other than zero, so it should only be used for
6615 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6616
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6617<p>Note that calling this intrinsic does not prevent function inlining or other
6618 aggressive transformations, so the value returned may not be that of the
6619 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6620
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6621</div>
6622
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6623<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6624<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6625 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6626</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6627
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6628<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6629
6630<h5>Syntax:</h5>
6631<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6632 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6633</pre>
6634
6635<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6636<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6637 of the function stack, for use
6638 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6639 useful for implementing language features like scoped automatic variable
6640 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6643<p>This intrinsic returns a opaque pointer value that can be passed
6644 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6645 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6646 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6647 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6648 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6649 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6650
6651</div>
6652
6653<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6654<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6655 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6656</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6657
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6658<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6659
6660<h5>Syntax:</h5>
6661<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6662 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6663</pre>
6664
6665<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6666<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6667 the function stack to the state it was in when the
6668 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6669 executed. This is useful for implementing language features like scoped
6670 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6671
6672<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6673<p>See the description
6674 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6675
6676</div>
6677
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6678<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6679<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6680 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6681</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6682
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6683<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6684
6685<h5>Syntax:</h5>
6686<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6687 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]6688</pre>
6689
6690<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6691<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6692 insert a prefetch instruction if supported; otherwise, it is a noop.
6693 Prefetches have no effect on the behavior of the program but can change its
6694 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6695
6696<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6697<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6698 specifier determining if the fetch should be for a read (0) or write (1),
6699 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6700 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6701 specifies whether the prefetch is performed on the data (1) or instruction (0)
6702 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6703 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6704
6705<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6706<p>This intrinsic does not modify the behavior of the program. In particular,
6707 prefetches cannot trap and do not produce a value. On targets that support
6708 this intrinsic, the prefetch can provide hints to the processor cache for
6709 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6710
6711</div>
6712
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6713<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6714<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6715 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6716</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6717
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6718<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6719
6720<h5>Syntax:</h5>
6721<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6722 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6723</pre>
6724
6725<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6726<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6727 Counter (PC) in a region of code to simulators and other tools. The method
6728 is target specific, but it is expected that the marker will use exported
6729 symbols to transmit the PC of the marker. The marker makes no guarantees
6730 that it will remain with any specific instruction after optimizations. It is
6731 possible that the presence of a marker will inhibit optimizations. The
6732 intended use is to be inserted after optimizations to allow correlations of
6733 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6734
6735<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6736<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6737
6738<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6739<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6740 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6741
6742</div>
6743
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6744<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6745<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6746 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6747</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6748
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6749<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6750
6751<h5>Syntax:</h5>
6752<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6753 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6754</pre>
6755
6756<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6757<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6758 counter register (or similar low latency, high accuracy clocks) on those
6759 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6760 should map to RPCC. As the backing counters overflow quickly (on the order
6761 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6762
6763<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6764<p>When directly supported, reading the cycle counter should not modify any
6765 memory. Implementations are allowed to either return a application specific
6766 value or a system wide value. On backends without support, this is lowered
6767 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6768
6769</div>
6770
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6771</div>
6772
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6773<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6774<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6775 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6776</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6777
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6778<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6779
6780<p>LLVM provides intrinsics for a few important standard C library functions.
6781 These intrinsics allow source-language front-ends to pass information about
6782 the alignment of the pointer arguments to the code generator, providing
6783 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6784
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6785<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6786<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6787 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6788</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6789
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6790<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6791
6792<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6793<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]6794 integer bit width and for different address spaces. Not all targets support
6795 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6796
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6797<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6798 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]6799 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6800 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]6801 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6802</pre>
6803
6804<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6805<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6806 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6807
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6808<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6809 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6810 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6811
6812<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6813
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6814<p>The first argument is a pointer to the destination, the second is a pointer
6815 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6816 number of bytes to copy, the fourth argument is the alignment of the
6817 source and destination locations, and the fifth is a boolean indicating a
6818 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6819
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6820<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]6821 then the caller guarantees that both the source and destination pointers are
6822 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6823
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6824<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6825 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6826 The detailed access behavior is not very cleanly specified and it is unwise
6827 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6828
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6829<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6830
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6831<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6832 source location to the destination location, which are not allowed to
6833 overlap. It copies "len" bytes of memory over. If the argument is known to
6834 be aligned to some boundary, this can be specified as the fourth argument,
6835 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6836
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6837</div>
6838
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6839<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6840<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6841 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6842</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6843
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6844<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6845
6846<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6847<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]6848 width and for different address space. Not all targets support all bit
6849 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6850
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6851<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6852 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]6853 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6854 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]6855 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6856</pre>
6857
6858<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6859<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6860 source location to the destination location. It is similar to the
6861 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6862 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6863
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6864<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6865 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6866 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6867
6868<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6869
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6870<p>The first argument is a pointer to the destination, the second is a pointer
6871 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6872 number of bytes to copy, the fourth argument is the alignment of the
6873 source and destination locations, and the fifth is a boolean indicating a
6874 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6875
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6876<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]6877 then the caller guarantees that the source and destination pointers are
6878 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6879
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6880<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6881 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6882 The detailed access behavior is not very cleanly specified and it is unwise
6883 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6884
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6885<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6886
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6887<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6888 source location to the destination location, which may overlap. It copies
6889 "len" bytes of memory over. If the argument is known to be aligned to some
6890 boundary, this can be specified as the fourth argument, otherwise it should
6891 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6892
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6893</div>
6894
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6895<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6896<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6897 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6898</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6899
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6900<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6901
6902<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6903<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]6904 width and for different address spaces. However, not all targets support all
6905 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6906
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6907<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6908 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6909 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6910 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6911 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6912</pre>
6913
6914<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6915<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6916 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6917
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6918<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6919 intrinsic does not return a value and takes extra alignment/volatile
6920 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6921
6922<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6923<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]6924 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6925 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6926 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6927
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6928<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]6929 then the caller guarantees that the destination pointer is aligned to that
6930 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6931
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6932<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6933 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6934 The detailed access behavior is not very cleanly specified and it is unwise
6935 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6936
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6937<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6938<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6939 at the destination location. If the argument is known to be aligned to some
6940 boundary, this can be specified as the fourth argument, otherwise it should
6941 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6942
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6943</div>
6944
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6945<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6946<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6947 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6948</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6949
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6950<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6951
6952<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6953<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6954 floating point or vector of floating point type. Not all targets support all
6955 types however.</p>
6956
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6957<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6958 declare float @llvm.sqrt.f32(float %Val)
6959 declare double @llvm.sqrt.f64(double %Val)
6960 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6961 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6962 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6963</pre>
6964
6965<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6966<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6967 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6968 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6969 behavior for negative numbers other than -0.0 (which allows for better
6970 optimization, because there is no need to worry about errno being
6971 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]6972
6973<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6974<p>The argument and return value are floating point numbers of the same
6975 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6976
6977<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6978<p>This function returns the sqrt of the specified operand if it is a
6979 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6980
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6981</div>
6982
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6983<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6984<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6985 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6986</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6987
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6988<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6989
6990<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6991<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6992 floating point or vector of floating point type. Not all targets support all
6993 types however.</p>
6994
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6995<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6996 declare float @llvm.powi.f32(float %Val, i32 %power)
6997 declare double @llvm.powi.f64(double %Val, i32 %power)
6998 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6999 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7000 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7001</pre>
7002
7003<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7004<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7005 specified (positive or negative) power. The order of evaluation of
7006 multiplications is not defined. When a vector of floating point type is
7007 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7008
7009<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7010<p>The second argument is an integer power, and the first is a value to raise to
7011 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7012
7013<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7014<p>This function returns the first value raised to the second power with an
7015 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7016
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7017</div>
7018
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7019<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7020<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7021 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7022</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7023
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7024<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7025
7026<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7027<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7028 floating point or vector of floating point type. Not all targets support all
7029 types however.</p>
7030
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7031<pre>
7032 declare float @llvm.sin.f32(float %Val)
7033 declare double @llvm.sin.f64(double %Val)
7034 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7035 declare fp128 @llvm.sin.f128(fp128 %Val)
7036 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7037</pre>
7038
7039<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7040<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7041
7042<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7043<p>The argument and return value are floating point numbers of the same
7044 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7045
7046<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7047<p>This function returns the sine of the specified operand, returning the same
7048 values as the libm <tt>sin</tt> functions would, and handles error conditions
7049 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7050
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7051</div>
7052
7053<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7054<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7055 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7056</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7057
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7058<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7059
7060<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7061<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7062 floating point or vector of floating point type. Not all targets support all
7063 types however.</p>
7064
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7065<pre>
7066 declare float @llvm.cos.f32(float %Val)
7067 declare double @llvm.cos.f64(double %Val)
7068 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7069 declare fp128 @llvm.cos.f128(fp128 %Val)
7070 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7071</pre>
7072
7073<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7074<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7075
7076<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7077<p>The argument and return value are floating point numbers of the same
7078 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7079
7080<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7081<p>This function returns the cosine of the specified operand, returning the same
7082 values as the libm <tt>cos</tt> functions would, and handles error conditions
7083 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7084
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7085</div>
7086
7087<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7088<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7089 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7090</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7091
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7092<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7093
7094<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7095<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7096 floating point or vector of floating point type. Not all targets support all
7097 types however.</p>
7098
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7099<pre>
7100 declare float @llvm.pow.f32(float %Val, float %Power)
7101 declare double @llvm.pow.f64(double %Val, double %Power)
7102 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7103 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7104 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7105</pre>
7106
7107<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7108<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7109 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7110
7111<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7112<p>The second argument is a floating point power, and the first is a value to
7113 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7114
7115<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7116<p>This function returns the first value raised to the second power, returning
7117 the same values as the libm <tt>pow</tt> functions would, and handles error
7118 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7119
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7120</div>
7121
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7122<!-- _______________________________________________________________________ -->
7123<h4>
7124 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7125</h4>
7126
7127<div>
7128
7129<h5>Syntax:</h5>
7130<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7131 floating point or vector of floating point type. Not all targets support all
7132 types however.</p>
7133
7134<pre>
7135 declare float @llvm.exp.f32(float %Val)
7136 declare double @llvm.exp.f64(double %Val)
7137 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7138 declare fp128 @llvm.exp.f128(fp128 %Val)
7139 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7140</pre>
7141
7142<h5>Overview:</h5>
7143<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7144
7145<h5>Arguments:</h5>
7146<p>The argument and return value are floating point numbers of the same
7147 type.</p>
7148
7149<h5>Semantics:</h5>
7150<p>This function returns the same values as the libm <tt>exp</tt> functions
7151 would, and handles error conditions in the same way.</p>
7152
7153</div>
7154
7155<!-- _______________________________________________________________________ -->
7156<h4>
7157 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7158</h4>
7159
7160<div>
7161
7162<h5>Syntax:</h5>
7163<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7164 floating point or vector of floating point type. Not all targets support all
7165 types however.</p>
7166
7167<pre>
7168 declare float @llvm.log.f32(float %Val)
7169 declare double @llvm.log.f64(double %Val)
7170 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7171 declare fp128 @llvm.log.f128(fp128 %Val)
7172 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7173</pre>
7174
7175<h5>Overview:</h5>
7176<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7177
7178<h5>Arguments:</h5>
7179<p>The argument and return value are floating point numbers of the same
7180 type.</p>
7181
7182<h5>Semantics:</h5>
7183<p>This function returns the same values as the libm <tt>log</tt> functions
7184 would, and handles error conditions in the same way.</p>
7185
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7186</div>
7187
7188<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7189<h4>
7190 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7191</h4>
7192
7193<div>
7194
7195<h5>Syntax:</h5>
7196<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7197 floating point or vector of floating point type. Not all targets support all
7198 types however.</p>
7199
7200<pre>
7201 declare float @llvm.fma.f32(float %a, float %b, float %c)
7202 declare double @llvm.fma.f64(double %a, double %b, double %c)
7203 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7204 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7205 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7206</pre>
7207
7208<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7209<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7210 operation.</p>
7211
7212<h5>Arguments:</h5>
7213<p>The argument and return value are floating point numbers of the same
7214 type.</p>
7215
7216<h5>Semantics:</h5>
7217<p>This function returns the same values as the libm <tt>fma</tt> functions
7218 would.</p>
7219
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7220</div>
7221
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7222</div>
7223
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7224<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7225<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7226 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7227</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7228
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7229<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7230
7231<p>LLVM provides intrinsics for a few important bit manipulation operations.
7232 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7233
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7234<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7235<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7236 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7237</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7238
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7239<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7240
7241<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7242<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7243 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7244
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7245<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7246 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7247 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7248 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7249</pre>
7250
7251<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7252<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7253 values with an even number of bytes (positive multiple of 16 bits). These
7254 are useful for performing operations on data that is not in the target's
7255 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7256
7257<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7258<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7259 and low byte of the input i16 swapped. Similarly,
7260 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7261 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7262 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7263 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7264 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7265 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7266
7267</div>
7268
7269<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7270<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7271 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7272</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7273
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7274<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7275
7276<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7277<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]7278 width, or on any vector with integer elements. Not all targets support all
7279 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7280
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7281<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7282 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7283 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7284 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7285 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7286 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7287 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]7288</pre>
7289
7290<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7291<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7292 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7293
7294<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7295<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]7296 integer type, or a vector with integer elements.
7297 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7298
7299<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7300<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7301 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7302
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7303</div>
7304
7305<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7306<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7307 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7308</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7309
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7310<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7311
7312<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7313<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]7314 integer bit width, or any vector whose elements are integers. Not all
7315 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7316
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7317<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7318 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7319 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7320 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7321 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7322 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7323 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]7324</pre>
7325
7326<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7327<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7328 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7329
7330<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7331<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]7332 integer type, or any vector type with integer element type.
7333 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7334
7335<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7336<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7337 zeros in a variable, or within each element of the vector if the operation
7338 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]7339 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7340
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7341</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7342
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7343<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7344<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7345 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7346</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7347
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7348<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7349
7350<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7351<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]7352 integer bit width, or any vector of integer elements. Not all targets
7353 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7354
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7355<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7356 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7357 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7358 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7359 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7360 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7361 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]7362</pre>
7363
7364<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7365<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7366 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7367
7368<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7369<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]7370 integer type, or a vectory with integer element type.. The return type
7371 must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7372
7373<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7374<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7375 zeros in a variable, or within each element of a vector.
7376 If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7377 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7378
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7379</div>
7380
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7381</div>
7382
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7383<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7384<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7385 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7386</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7387
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7388<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7389
7390<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7391
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7392<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7393<h4>
7394 <a name="int_sadd_overflow">
7395 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7396 </a>
7397</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7398
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7399<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7400
7401<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7402<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]7403 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7404
7405<pre>
7406 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7407 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7408 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7409</pre>
7410
7411<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7412<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7413 a signed addition of the two arguments, and indicate whether an overflow
7414 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7415
7416<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7417<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]7418 be of integer types of any bit width, but they must have the same bit
7419 width. The second element of the result structure must be of
7420 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7421 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7422
7423<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7424<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7425 a signed addition of the two variables. They return a structure &mdash; the
7426 first element of which is the signed summation, and the second element of
7427 which is a bit specifying if the signed summation resulted in an
7428 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7429
7430<h5>Examples:</h5>
7431<pre>
7432 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7433 %sum = extractvalue {i32, i1} %res, 0
7434 %obit = extractvalue {i32, i1} %res, 1
7435 br i1 %obit, label %overflow, label %normal
7436</pre>
7437
7438</div>
7439
7440<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7441<h4>
7442 <a name="int_uadd_overflow">
7443 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7444 </a>
7445</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7446
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7447<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7448
7449<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7450<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]7451 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7452
7453<pre>
7454 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7455 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7456 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7457</pre>
7458
7459<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7460<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7461 an unsigned addition of the two arguments, and indicate whether a carry
7462 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7463
7464<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7465<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]7466 be of integer types of any bit width, but they must have the same bit
7467 width. The second element of the result structure must be of
7468 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7469 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7470
7471<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7472<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7473 an unsigned addition of the two arguments. They return a structure &mdash;
7474 the first element of which is the sum, and the second element of which is a
7475 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7476
7477<h5>Examples:</h5>
7478<pre>
7479 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7480 %sum = extractvalue {i32, i1} %res, 0
7481 %obit = extractvalue {i32, i1} %res, 1
7482 br i1 %obit, label %carry, label %normal
7483</pre>
7484
7485</div>
7486
7487<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7488<h4>
7489 <a name="int_ssub_overflow">
7490 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7491 </a>
7492</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7493
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7494<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7495
7496<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7497<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]7498 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7499
7500<pre>
7501 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7502 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7503 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7504</pre>
7505
7506<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7507<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7508 a signed subtraction of the two arguments, and indicate whether an overflow
7509 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7510
7511<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7512<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]7513 be of integer types of any bit width, but they must have the same bit
7514 width. The second element of the result structure must be of
7515 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7516 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7517
7518<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7519<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7520 a signed subtraction of the two arguments. They return a structure &mdash;
7521 the first element of which is the subtraction, and the second element of
7522 which is a bit specifying if the signed subtraction resulted in an
7523 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7524
7525<h5>Examples:</h5>
7526<pre>
7527 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7528 %sum = extractvalue {i32, i1} %res, 0
7529 %obit = extractvalue {i32, i1} %res, 1
7530 br i1 %obit, label %overflow, label %normal
7531</pre>
7532
7533</div>
7534
7535<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7536<h4>
7537 <a name="int_usub_overflow">
7538 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7539 </a>
7540</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7541
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7542<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7543
7544<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7545<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]7546 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7547
7548<pre>
7549 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7550 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7551 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7552</pre>
7553
7554<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7555<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7556 an unsigned subtraction of the two arguments, and indicate whether an
7557 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7558
7559<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7560<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]7561 be of integer types of any bit width, but they must have the same bit
7562 width. The second element of the result structure must be of
7563 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7564 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7565
7566<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7567<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7568 an unsigned subtraction of the two arguments. They return a structure &mdash;
7569 the first element of which is the subtraction, and the second element of
7570 which is a bit specifying if the unsigned subtraction resulted in an
7571 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7572
7573<h5>Examples:</h5>
7574<pre>
7575 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7576 %sum = extractvalue {i32, i1} %res, 0
7577 %obit = extractvalue {i32, i1} %res, 1
7578 br i1 %obit, label %overflow, label %normal
7579</pre>
7580
7581</div>
7582
7583<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7584<h4>
7585 <a name="int_smul_overflow">
7586 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7587 </a>
7588</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7589
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7590<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7591
7592<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7593<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]7594 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7595
7596<pre>
7597 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7598 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7599 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7600</pre>
7601
7602<h5>Overview:</h5>
7603
7604<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7605 a signed multiplication of the two arguments, and indicate whether an
7606 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7607
7608<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7609<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]7610 be of integer types of any bit width, but they must have the same bit
7611 width. The second element of the result structure must be of
7612 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7613 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7614
7615<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7616<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7617 a signed multiplication of the two arguments. They return a structure &mdash;
7618 the first element of which is the multiplication, and the second element of
7619 which is a bit specifying if the signed multiplication resulted in an
7620 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7621
7622<h5>Examples:</h5>
7623<pre>
7624 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7625 %sum = extractvalue {i32, i1} %res, 0
7626 %obit = extractvalue {i32, i1} %res, 1
7627 br i1 %obit, label %overflow, label %normal
7628</pre>
7629
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7630</div>
7631
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7632<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7633<h4>
7634 <a name="int_umul_overflow">
7635 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7636 </a>
7637</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7638
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7639<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7640
7641<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7642<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]7643 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7644
7645<pre>
7646 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7647 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7648 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7649</pre>
7650
7651<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7652<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7653 a unsigned multiplication of the two arguments, and indicate whether an
7654 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7655
7656<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7657<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]7658 be of integer types of any bit width, but they must have the same bit
7659 width. The second element of the result structure must be of
7660 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7661 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7662
7663<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7664<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7665 an unsigned multiplication of the two arguments. They return a structure
7666 &mdash; the first element of which is the multiplication, and the second
7667 element of which is a bit specifying if the unsigned multiplication resulted
7668 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7669
7670<h5>Examples:</h5>
7671<pre>
7672 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7673 %sum = extractvalue {i32, i1} %res, 0
7674 %obit = extractvalue {i32, i1} %res, 1
7675 br i1 %obit, label %overflow, label %normal
7676</pre>
7677
7678</div>
7679
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7680</div>
7681
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7682<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7683<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7684 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7685</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7686
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7687<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7688
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7689<p>Half precision floating point is a storage-only format. This means that it is
7690 a dense encoding (in memory) but does not support computation in the
7691 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7692
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7693<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7694 value as an i16, then convert it to float with <a
7695 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7696 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7697 double etc). To store the value back to memory, it is first converted to
7698 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7699 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7700 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7701
7702<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7703<h4>
7704 <a name="int_convert_to_fp16">
7705 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7706 </a>
7707</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7708
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7709<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7710
7711<h5>Syntax:</h5>
7712<pre>
7713 declare i16 @llvm.convert.to.fp16(f32 %a)
7714</pre>
7715
7716<h5>Overview:</h5>
7717<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7718 a conversion from single precision floating point format to half precision
7719 floating point format.</p>
7720
7721<h5>Arguments:</h5>
7722<p>The intrinsic function contains single argument - the value to be
7723 converted.</p>
7724
7725<h5>Semantics:</h5>
7726<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7727 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7728 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7729 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7730
7731<h5>Examples:</h5>
7732<pre>
7733 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7734 store i16 %res, i16* @x, align 2
7735</pre>
7736
7737</div>
7738
7739<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7740<h4>
7741 <a name="int_convert_from_fp16">
7742 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7743 </a>
7744</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7745
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7746<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7747
7748<h5>Syntax:</h5>
7749<pre>
7750 declare f32 @llvm.convert.from.fp16(i16 %a)
7751</pre>
7752
7753<h5>Overview:</h5>
7754<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7755 a conversion from half precision floating point format to single precision
7756 floating point format.</p>
7757
7758<h5>Arguments:</h5>
7759<p>The intrinsic function contains single argument - the value to be
7760 converted.</p>
7761
7762<h5>Semantics:</h5>
7763<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7764 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7765 precision floating point format. The input half-float value is represented by
7766 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7767
7768<h5>Examples:</h5>
7769<pre>
7770 %a = load i16* @x, align 2
7771 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7772</pre>
7773
7774</div>
7775
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7776</div>
7777
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7778<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7779<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7780 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7781</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7782
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7783<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7784
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7785<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7786 prefix), are described in
7787 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7788 Level Debugging</a> document.</p>
7789
7790</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7791
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7792<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7793<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7794 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7795</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7796
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7797<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7798
7799<p>The LLVM exception handling intrinsics (which all start with
7800 <tt>llvm.eh.</tt> prefix), are described in
7801 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7802 Handling</a> document.</p>
7803
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7804</div>
7805
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7806<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7807<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7808 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7809</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7810
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7811<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7812
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7813<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7814 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7815 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7816 function pointer lacking the nest parameter - the caller does not need to
7817 provide a value for it. Instead, the value to use is stored in advance in a
7818 "trampoline", a block of memory usually allocated on the stack, which also
7819 contains code to splice the nest value into the argument list. This is used
7820 to implement the GCC nested function address extension.</p>
7821
7822<p>For example, if the function is
7823 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7824 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7825 follows:</p>
7826
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7827<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7828 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7829 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7830 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7831 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7832 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7833</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7834
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7835<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7836 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7837
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7838<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7839<h4>
7840 <a name="int_it">
7841 '<tt>llvm.init.trampoline</tt>' Intrinsic
7842 </a>
7843</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7844
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7845<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7846
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7847<h5>Syntax:</h5>
7848<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7849 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]7850</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7851
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7852<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7853<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7854 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7855
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7856<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7857<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7858 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7859 sufficiently aligned block of memory; this memory is written to by the
7860 intrinsic. Note that the size and the alignment are target-specific - LLVM
7861 currently provides no portable way of determining them, so a front-end that
7862 generates this intrinsic needs to have some target-specific knowledge.
7863 The <tt>func</tt> argument must hold a function bitcast to
7864 an <tt>i8*</tt>.</p>
7865
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7866<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7867<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]7868 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7869 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7870 which can be <a href="#int_trampoline">bitcast (to a new function) and
7871 called</a>. The new function's signature is the same as that of
7872 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7873 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7874 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7875 with the same argument list, but with <tt>nval</tt> used for the missing
7876 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7877 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7878 to the returned function pointer is undefined.</p>
7879</div>
7880
7881<!-- _______________________________________________________________________ -->
7882<h4>
7883 <a name="int_at">
7884 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7885 </a>
7886</h4>
7887
7888<div>
7889
7890<h5>Syntax:</h5>
7891<pre>
7892 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7893</pre>
7894
7895<h5>Overview:</h5>
7896<p>This performs any required machine-specific adjustment to the address of a
7897 trampoline (passed as <tt>tramp</tt>).</p>
7898
7899<h5>Arguments:</h5>
7900<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7901 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7902 </a>.</p>
7903
7904<h5>Semantics:</h5>
7905<p>On some architectures the address of the code to be executed needs to be
7906 different to the address where the trampoline is actually stored. This
7907 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7908 after performing the required machine specific adjustments.
7909 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7910 executed</a>.
7911</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7912
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7913</div>
7914
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7915</div>
7916
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7917<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7918<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7919 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7920</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7921
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7922<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7923
7924<p>This class of intrinsics exists to information about the lifetime of memory
7925 objects and ranges where variables are immutable.</p>
7926
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7927<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7928<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7929 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7930</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7931
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7932<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7933
7934<h5>Syntax:</h5>
7935<pre>
7936 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7937</pre>
7938
7939<h5>Overview:</h5>
7940<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7941 object's lifetime.</p>
7942
7943<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7944<p>The first argument is a constant integer representing the size of the
7945 object, or -1 if it is variable sized. The second argument is a pointer to
7946 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7947
7948<h5>Semantics:</h5>
7949<p>This intrinsic indicates that before this point in the code, the value of the
7950 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]7951 never be used and has an undefined value. A load from the pointer that
7952 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7953 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7954
7955</div>
7956
7957<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7958<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7959 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7960</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7961
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7962<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7963
7964<h5>Syntax:</h5>
7965<pre>
7966 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7967</pre>
7968
7969<h5>Overview:</h5>
7970<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7971 object's lifetime.</p>
7972
7973<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7974<p>The first argument is a constant integer representing the size of the
7975 object, or -1 if it is variable sized. The second argument is a pointer to
7976 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7977
7978<h5>Semantics:</h5>
7979<p>This intrinsic indicates that after this point in the code, the value of the
7980 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7981 never be used and has an undefined value. Any stores into the memory object
7982 following this intrinsic may be removed as dead.
7983
7984</div>
7985
7986<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7987<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7988 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7989</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7990
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7991<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7992
7993<h5>Syntax:</h5>
7994<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]7995 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7996</pre>
7997
7998<h5>Overview:</h5>
7999<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8000 a memory object will not change.</p>
8001
8002<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8003<p>The first argument is a constant integer representing the size of the
8004 object, or -1 if it is variable sized. The second argument is a pointer to
8005 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8006
8007<h5>Semantics:</h5>
8008<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8009 the return value, the referenced memory location is constant and
8010 unchanging.</p>
8011
8012</div>
8013
8014<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8015<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8016 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8017</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8018
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8019<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8020
8021<h5>Syntax:</h5>
8022<pre>
8023 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8024</pre>
8025
8026<h5>Overview:</h5>
8027<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8028 a memory object are mutable.</p>
8029
8030<h5>Arguments:</h5>
8031<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8032 The second argument is a constant integer representing the size of the
8033 object, or -1 if it is variable sized and the third argument is a pointer
8034 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8035
8036<h5>Semantics:</h5>
8037<p>This intrinsic indicates that the memory is mutable again.</p>
8038
8039</div>
8040
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8041</div>
8042
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8043<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8044<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8045 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8046</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8047
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8048<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8049
8050<p>This class of intrinsics is designed to be generic and has no specific
8051 purpose.</p>
8052
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8053<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8054<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8055 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8056</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8057
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8058<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8059
8060<h5>Syntax:</h5>
8061<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8062 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]8063</pre>
8064
8065<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8066<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8067
8068<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8069<p>The first argument is a pointer to a value, the second is a pointer to a
8070 global string, the third is a pointer to a global string which is the source
8071 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8072
8073<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8074<p>This intrinsic allows annotation of local variables with arbitrary strings.
8075 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8076 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8077 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8078
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8079</div>
8080
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8081<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8082<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8083 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8084</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8085
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8086<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8087
8088<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8089<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8090 any integer bit width.</p>
8091
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8092<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8093 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8094 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8095 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8096 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8097 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]8098</pre>
8099
8100<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8101<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8102
8103<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8104<p>The first argument is an integer value (result of some expression), the
8105 second is a pointer to a global string, the third is a pointer to a global
8106 string which is the source file name, and the last argument is the line
8107 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8108
8109<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8110<p>This intrinsic allows annotations to be put on arbitrary expressions with
8111 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8112 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8113 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8114
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8115</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8116
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8117<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8118<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8119 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8120</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8121
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8122<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8123
8124<h5>Syntax:</h5>
8125<pre>
8126 declare void @llvm.trap()
8127</pre>
8128
8129<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8130<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8131
8132<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8133<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8134
8135<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8136<p>This intrinsics is lowered to the target dependent trap instruction. If the
8137 target does not have a trap instruction, this intrinsic will be lowered to
8138 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8139
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8140</div>
8141
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8142<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8143<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8144 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8145</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8146
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8147<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8148
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8149<h5>Syntax:</h5>
8150<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8151 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8152</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8153
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8154<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8155<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8156 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8157 ensure that it is placed on the stack before local variables.</p>
8158
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8159<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8160<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8161 arguments. The first argument is the value loaded from the stack
8162 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8163 that has enough space to hold the value of the guard.</p>
8164
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8165<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8166<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8167 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8168 stack. This is to ensure that if a local variable on the stack is
8169 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8170 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8171 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8172 function.</p>
8173
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8174</div>
8175
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8176<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8177<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8178 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8179</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8180
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8181<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8182
8183<h5>Syntax:</h5>
8184<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8185 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8186 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8187</pre>
8188
8189<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8190<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8191 the optimizers to determine at compile time whether a) an operation (like
8192 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8193 runtime check for overflow isn't necessary. An object in this context means
8194 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8195
8196<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8197<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8198 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8199 is a boolean 0 or 1. This argument determines whether you want the
8200 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]8201 1, variables are not allowed.</p>
8202
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8203<h5>Semantics:</h5>
8204<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8205 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8206 depending on the <tt>type</tt> argument, if the size cannot be determined at
8207 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8208
8209</div>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8210<!-- _______________________________________________________________________ -->
8211<h4>
8212 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8213</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8214
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8215<div>
8216
8217<h5>Syntax:</h5>
8218<pre>
8219 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8220 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8221</pre>
8222
8223<h5>Overview:</h5>
8224<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8225 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8226
8227<h5>Arguments:</h5>
8228<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8229 argument is a value. The second argument is an expected value, this needs to
8230 be a constant value, variables are not allowed.</p>
8231
8232<h5>Semantics:</h5>
8233<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8234</div>
8235
8236</div>
8237
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8238</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8239<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8240<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8241<address>
8242 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8243 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8244 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8245 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]8246
8247 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8248 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8249 Last modified: $Date$
8250</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8251
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8252</body>
8253</html>