Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / llvm / 8e1b12ae68cd6ae5180cb300a05bae5ddf0c49ae / . / docs / LangRef.html
blob: 2329bdb1c8bb36e55414c7d92b1cee9cef4a06c7 [file] [log] [blame]
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 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 Wendling987e7eb2009-07-20 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 Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 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 Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 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 Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 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 Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourne249d9532011-10-27 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 Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattner857755c2009-07-20 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 Lattner401e10c2009-07-20 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 Lattner857755c2009-07-20 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 Lattner00950542001-06-06 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 Lattner261efe92003-11-25 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 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 Spencer0a783f72006-11-02 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer8e11bf82007-02-02 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3df241e2006-04-08 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmana334d5f2008-05-12 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 Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanff030482011-07-28 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 Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 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 Spencerd4448792006-11-09 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 Spencer72679252006-11-11 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 Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerf3a70a62006-11-18 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencera3e435f2007-04-04 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencera3e435f2007-04-04 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 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 Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencera3e435f2007-04-04 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 Gohman91c284c2007-10-15 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 Gohman08b280b2011-05-27 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 Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingda01af72009-02-08 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]272 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]273 </ol>
274 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattner82c3dc62010-03-14 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]279 </ol>
280 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
Jakub Staszak8e1b12a2011-12-04 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 Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]295 </ol>
296 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 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 Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]309 <li><a href="#int_expect">
310 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattnerd7923912004-05-23 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]323<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]326<div>
Bill Wendlinge910b4c2009-07-20 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]337<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]340<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]361<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]362<h4>
363 <a name="wellformed">Well-Formedness</a>
364</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]366<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
376
Bill Wendlingf82d40a2009-11-02 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]383
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]384</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]385
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]386</div>
387
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]391<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]394<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]440<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]444<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]446<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448</pre>
449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]450<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]452<pre class="doc_code">
Gabor Greifec58f752009-10-28 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]455%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456</pre>
457
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]461<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
465 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]466 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]468 <li>Unnamed temporaries are numbered sequentially</li>
469</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]471<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]476</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477
478<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]479<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]481<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]483<h3>
484 <a name="modulestructure">Module Structure</a>
485</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]486
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]487<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]496<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]497<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
Chris Lattner63e4ccb2010-08-17 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
503<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
Chris Lattner63e4ccb2010-08-17 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 Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]512
513<i>; Named metadata</i>
514!1 = metadata !{i32 41}
515!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]516</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]520 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]521 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
522 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]530</div>
531
532<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]533<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]534 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]535</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]537<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539<p>All Global Variables and Functions have one of the following types of
540 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]541
542<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 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 Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]550
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 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 Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]562
Bill Wendling55ae5152010-08-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]572 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]573 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]576
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]578 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 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 Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]585
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]586 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]587 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]599
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]600 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 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 Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]613 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]614 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
615 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]616
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]619 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 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 Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]624
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]625 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]629
Bill Wendlingf82d40a2009-11-02 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 Wendlinge910b4c2009-07-20 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 Wendling5e721d72010-07-01 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 Wendlinge910b4c2009-07-20 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 Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]639
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]641 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 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 Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]644</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]645
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]651 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]652 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]658 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]659 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]664</dl>
665
Bill Wendlinge910b4c2009-07-20 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 Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]673 other than <tt>external</tt>, <tt>dllimport</tt>
674 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]676<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]677 or <tt>weak_odr</tt> linkages.</p>
678
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]679</div>
680
681<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]682<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]683 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]684</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]686<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]687
688<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<dl>
696 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702
703 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]704 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 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 Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]708 (Application Binary Interface).
709 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713
714 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]715 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]721
Chris Lattner29689432010-03-11 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 Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]742 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]743 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]744 target-specific calling conventions to be used. Target specific calling
745 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]746</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]747
748<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749 support Pascal conventions or any other well-known target-independent
750 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]751
752</div>
753
754<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]755<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]756 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]757</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]759<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]761<p>All Global Variables and Functions have one of the following visibility
762 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
764<dl>
765 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]766 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771
772 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]773 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]778
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]779 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]780 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]784</dl>
785
786</div>
787
788<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]789<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]791</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]792
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]793<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]794
795<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]799<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800%mytype = type { %mytype*, i32 }
801</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]804 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]805 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]806
807<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 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 Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]816
817</div>
818
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]819<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]820<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]822</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]823
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]824<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]825
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]826<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 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 Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]837
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Rafael Espindolabea46262011-01-08 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 Espindolaa5eaa862011-01-15 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 Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]857
Bill Wendlinge910b4c2009-07-20 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 Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]863
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]865 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]866
Chris Lattnerce99fa92010-04-28 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 Lattner2d4b8ee2010-04-28 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]876
Bill Wendlinge910b4c2009-07-20 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 Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]879
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]880<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]881@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]882</pre>
883
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]884</div>
885
886
887<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]888<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]890</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]892<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]893
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]894<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 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 Espindolabea46262011-01-08 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 Wendlinge910b4c2009-07-20 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 Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]905
Bill Wendlinge910b4c2009-07-20 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]908 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 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 Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]914
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]915<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]920
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]921<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]929
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]930<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]935
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]936<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]937 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]938
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]939<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]940<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]941define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 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 Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]947
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]948</div>
949
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]950<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]951<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]953</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]955<div>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]961
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]962<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]963<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]964@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]965</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]966
967</div>
968
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]969<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]970<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]971 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]972</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]973
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]974<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]977 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]978 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]979
980<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]981<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]982; Some unnamed metadata nodes, which are referenced by the named metadata.
983!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]984!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]986; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]987!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]988</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]989
990</div>
991
992<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]993<h3>
994 <a name="paramattrs">Parameter Attributes</a>
995</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]997<div>
Bill Wendlinge910b4c2009-07-20 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 Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1009
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1010<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1011declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1012declare i32 @atoi(i8 zeroext)
1013declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1014</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1015
Bill Wendlinge910b4c2009-07-20 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1021<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1022 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1023 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 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 Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 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 Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1033
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1034 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1040
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1041 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 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 Wendlinge910b4c2009-07-20 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 Lattnera6fd81d2010-11-20 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1060 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 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 Gohmanefca7f92010-07-02 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 Gohman1e109622010-07-02 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 Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1080 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1081<br>
John McCall191d4ee2010-07-06 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 Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1084 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1090 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1095 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1100
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1101</div>
1102
1103<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1104<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1106</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1107
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1108<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1109
Bill Wendlinge910b4c2009-07-20 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 Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1113<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1114define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1115</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1116
1117<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 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 Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1121</div>
1122
1123<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1124<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1125 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1126</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1127
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1128<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1129
Bill Wendlinge910b4c2009-07-20 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 Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1134
Bill Wendlinge910b4c2009-07-20 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 Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1137
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1138<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1139define void @f() noinline { ... }
1140define void @f() alwaysinline { ... }
1141define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1142define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1143</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1144
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1145<dl>
Charles Davis1e063d12010-02-12 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1151 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1155
Dan Gohman129bd562011-06-16 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 Olesen570a4a52010-02-06 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 Lewycky76ec37a2010-07-06 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1173 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1177
Nick Lewycky76ec37a2010-07-06 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 Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1186
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1187 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1191
Nick Lewycky76ec37a2010-07-06 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1207
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1218
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1219 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1230 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 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 Wendlingc39e3e02009-07-20 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 Espindolafbff0ec2011-07-25 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 Espindola25456ef2011-10-03 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 Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1252</dl>
1253
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1254</div>
1255
1256<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1257<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1258 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1259</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1260
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1261<div>
Bill Wendlinge910b4c2009-07-20 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 Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1267
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1268<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1269module asm "inline asm code goes here"
1270module asm "more can go here"
1271</pre>
Chris Lattner4e9aba72006-01-23 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1275 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1276
Bill Wendlinge910b4c2009-07-20 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 Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1280</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1281
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1283<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1285</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1287<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 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 Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1293<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1294target datalayout = "<i>layout specification</i>"
1295</pre>
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1305 bits with the most significance have the lowest address location.</dd>
1306
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1307 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1308 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1309 the bits with the least significance have the lowest address
1310 location.</dd>
1311
Lang Hamesbb5b3f32011-10-10 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 Hames5f119a62011-10-11 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 Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1318
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1320 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1329 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1330 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331 <i>size</i>.</dd>
1332
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1334 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339
Reid Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1342 <i>size</i>.</dd>
1343
Daniel Dunbar87bde0b2009-06-08 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1346 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1352 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1353 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1356<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1357 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1361<ul>
1362 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1363 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 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 Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1368 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 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 Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1375 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1376</ul>
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1383 specification is used.</li>
1384
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1385 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1393 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1397</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1398
Chris Lattner6509f502011-10-11 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 Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1415</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1416
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1418<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1419 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1420</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1421
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1422<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1423
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1424<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1425with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 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 Gohman1e109622010-07-02 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 Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1432 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1437 no address.</li>
Dan Gohman556ca272009-07-27 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 Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1441 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1442 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 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 Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1465
1466<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 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 Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1469interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 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 Gohman556ca272009-07-27 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 Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1481<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1482<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1483 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1484</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1486<div>
Jeffrey Yasskin93e066d2010-04-26 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 Friedman5b60e1b2011-07-20 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 Friedman234bccd2011-08-22 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 Friedman5b60e1b2011-07-20 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 Friedmanff030482011-07-28 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 Friedman5b60e1b2011-07-20 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 Friedman118973a2011-07-22 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 Friedman5b60e1b2011-07-20 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 Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1542 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 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 Friedman5b60e1b2011-07-20 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 Friedman234bccd2011-08-22 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 Friedman5b60e1b2011-07-20 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 Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1558 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1559 <var>R<sub>byte</sub></var> returns the value written by that
1560 write.</li>
Eli Friedman118973a2011-07-22 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 Friedmanff030482011-07-28 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 Friedman5b60e1b2011-07-20 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 Friedman101c81d2011-08-02 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 Friedman5b60e1b2011-07-20 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 Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1597<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1598<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1599 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1600</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1601
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1602<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1603
1604<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 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 Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1608<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 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 Friedman234bccd2011-08-22 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 Friedmanff030482011-07-28 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 Friedman234bccd2011-08-22 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 Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1621<dl>
Eli Friedmanff030482011-07-28 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 Friedman234bccd2011-08-22 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 Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1647<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1648<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 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 Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1657<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 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 Friedmanff030482011-07-28 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 Friedman234bccd2011-08-22 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 Friedmanff030482011-07-28 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 Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1678</div>
1679
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1680<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1681<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1682<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1683
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1684<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1686<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 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 Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1693
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1694<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1695<h3>
1696 <a name="t_classifications">Type Classifications</a>
1697</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1698
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1699<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1700
1701<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1702
1703<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1705 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1707 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1708 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709 </tr>
1710 <tr>
Chris Lattner4f69f462008-01-04 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713 </tr>
1714 <tr>
1715 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 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 Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1719 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1720 <a href="#t_struct">structure</a>,
1721 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1722 <a href="#t_label">label</a>,
1723 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1724 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725 </tr>
Chris Lattner4f69f462008-01-04 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 Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1730 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1732 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1733 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1734 </tr>
1735 <tr>
1736 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1737 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 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 Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1741 <a href="#t_vector">vector</a>,
1742 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1743 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1744 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1745 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1750 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1755<h3>
1756 <a name="t_primitive">Primitive Types</a>
1757</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1759<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1761<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1762 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1763
1764<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1765<h4>
1766 <a name="t_integer">Integer Type</a>
1767</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1768
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1769<div>
Nick Lewyckyec38da42009-09-27 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1800</div>
1801
1802<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1803<h4>
1804 <a name="t_floating">Floating Point Types</a>
1805</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1806
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1807<div>
Bill Wendlinge910b4c2009-07-20 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 Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1820</div>
1821
1822<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1823<h4>
1824 <a name="t_x86mmx">X86mmx Type</a>
1825</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1826
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1827<div>
Dale Johannesen21fe99b2010-10-01 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 Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1834 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1835</pre>
1836
1837</div>
1838
1839<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1840<h4>
1841 <a name="t_void">Void Type</a>
1842</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1843
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1844<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1845
Chris Lattner4f69f462008-01-04 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 Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1850<pre>
1851 void
1852</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1853
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1854</div>
1855
1856<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1857<h4>
1858 <a name="t_label">Label Type</a>
1859</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1860
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1861<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1862
Chris Lattner4f69f462008-01-04 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 Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1867<pre>
1868 label
1869</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1870
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1871</div>
1872
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1873<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1874<h4>
1875 <a name="t_metadata">Metadata Type</a>
1876</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1878<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1879
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1880<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 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 Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1884
1885<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1886<pre>
1887 metadata
1888</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1889
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1890</div>
1891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1892</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1893
1894<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1895<h3>
1896 <a name="t_derived">Derived Types</a>
1897</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1898
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1899<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1900
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 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 Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1907
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1908<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1909<h4>
1910 <a name="t_aggregate">Aggregate Types</a>
1911</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1912
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1913<div>
Chris Lattnerfdfeb692010-02-12 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 Lattner61c70e92010-08-28 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 Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1919
1920</div>
1921
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1923<h4>
1924 <a name="t_array">Array Type</a>
1925</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1927<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1929<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1930<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1933
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1934<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1935<pre>
1936 [&lt;# elements&gt; x &lt;elementtype&gt;]
1937</pre>
1938
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1942<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1943<table class="layout">
1944 <tr class="layout">
Chris Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1955 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1956</table>
Reid Spencerd3f876c2004-11-01 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 Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1970 </tr>
1971</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1972
Dan Gohman7657f6b2009-11-09 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 Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1980</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1981
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1982<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1983<h4>
1984 <a name="t_function">Function Type</a>
1985</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1987<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1992 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1995<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1996 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1997</pre>
1998
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1999<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 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 Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2004 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2005 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2007<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2008<table class="layout">
2009 <tr class="layout">
Reid Spencer92f82302006-12-31 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2012 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2013 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2014 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2015 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2016 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 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 Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2019 </td>
2020 </tr><tr class="layout">
2021 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 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 Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2025 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2026 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2027 </tr><tr class="layout">
2028 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 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 Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2031 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2032 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2033</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2034
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2035</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2036
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2037<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2038<h4>
2039 <a name="t_struct">Structure Type</a>
2040</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2042<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2043
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2045<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2046 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2047
Jeffrey Yasskin7a088cf2010-01-11 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 Lattner1afcace2011-07-09 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 Lattner2c38d652011-08-12 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 Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2059 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2060
Chris Lattner2c38d652011-08-12 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 Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2065 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2066 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2067</p>
2068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2070<pre>
Chris Lattner2c38d652011-08-12 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 Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2073</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2074
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2076<table class="layout">
2077 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 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 Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2080 </tr>
2081 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2087 </tr>
Chris Lattner1afcace2011-07-09 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2093
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2094</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2095
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2096<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2097<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2098 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2099</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2101<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2103<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2107
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2108<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2109<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2110 %X = type opaque
2111 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2112</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2114<h5>Examples:</h5>
2115<table class="layout">
2116 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2117 <td class="left"><tt>opaque</tt></td>
2118 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2119 </tr>
2120</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2121
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2122</div>
2123
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2124
2125
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2126<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2127<h4>
2128 <a name="t_pointer">Pointer Type</a>
2129</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2130
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2131<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132
2133<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 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 Wendlinge910b4c2009-07-20 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 Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2144
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2145<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2146<pre>
2147 &lt;type&gt; *
2148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2149
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2150<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2151<table class="layout">
2152 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2153 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 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 Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2158 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2159 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2160 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2167 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2168</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2170</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2171
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2172<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2173<h4>
2174 <a name="t_vector">Vector Type</a>
2175</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2176
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2177<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2178
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2179<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2183 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2185
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2186<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2187<pre>
2188 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2189</pre>
2190
Chris Lattner7d2e7be2010-10-10 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 Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2194
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2195<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2196<table class="layout">
2197 <tr class="layout">
Chris Lattner23ff1f92007-12-19 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 Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2208 </tr>
2209</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2211</div>
2212
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2213</div>
2214
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2215</div>
2216
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2217<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2218<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2219<!-- *********************************************************************** -->
2220
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2221<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2222
2223<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2224 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2225
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2226<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2227<h3>
2228 <a name="simpleconstants">Simple Constants</a>
2229</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2230
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2231<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2232
2233<dl>
2234 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2235 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2236 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2237
2238 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2242
2243 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2244 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2250
2251 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2252 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2253 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2254</dl>
2255
Bill Wendlinge910b4c2009-07-20 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 Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2267<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 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 Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2280<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2281</div>
2282
2283<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2284<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2285<a name="aggregateconstants"></a> <!-- old anchor -->
2286<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2287</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2288
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2289<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2290
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2291<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2292 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2293
2294<dl>
2295 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2296 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2303
2304 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2305 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2311
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2312 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2313 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2319
2320 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2321 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 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 Wendlinge910b4c2009-07-20 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 Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2327
2328 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2329 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2334</dl>
2335
2336</div>
2337
2338<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2339<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2340 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2341</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2342
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2343<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2344
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2351
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2352<pre class="doc_code">
Chris Lattnera18a4242007-06-06 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2356</pre>
2357
2358</div>
2359
2360<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2361<h3>
2362 <a name="undefvalues">Undefined Values</a>
2363</h3>
2364
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2365<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2366
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2367<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2368 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2371
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2372<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2376
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2377
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2378<pre class="doc_code">
Chris Lattner48a109c2009-09-07 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 Lattner48a109c2009-09-07 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 Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2389 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2390
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2391<pre class="doc_code">
Chris Lattner48a109c2009-09-07 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 Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2401
2402<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 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 Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2411
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2412<pre class="doc_code">
Chris Lattner48a109c2009-09-07 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 Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2425
Bill Wendling1b383ba2010-10-27 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 Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2434
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2435<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2436 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2437
Chris Lattner48a109c2009-09-07 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 Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2453
Bill Wendling1b383ba2010-10-27 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 Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2465
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2466<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 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 Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2473
2474<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2486
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2487<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2488a: store undef -> %X
2489b: store %X -> undef
2490Safe:
2491a: &lt;deleted&gt;
2492b: unreachable
2493</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2494
Bill Wendling1b383ba2010-10-27 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 Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2500
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2501</div>
2502
2503<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2504<h3>
2505 <a name="trapvalues">Trap Values</a>
2506</h3>
2507
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2508<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2509
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2510<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 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 Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2514 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2515
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2516<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2517 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2518 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2519
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2520<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2521
Dan Gohman34b3d992010-04-28 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 Gohmanb5328162010-05-03 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 Gohman34b3d992010-04-28 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 Gohman7c24ff12010-05-03 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 Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2548
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2549<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2550
Dan Gohman34b3d992010-04-28 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 Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2553 the order in the IR. (This includes
2554 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2555
Dan Gohmanb5328162010-05-03 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 Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2560 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2561
Dan Gohmanca4cac42011-04-12 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 Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2564 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2565 successor.</li>
2566
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2567<li>Dependence is transitive.</li>
2568
2569</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2570
2571<p>Whenever a trap value is generated, all values which depend on it evaluate
Lang Hames87d5cb82011-10-13 23:04:49 +0000[diff] [blame]2572 to trap. If they have side effects, they evoke their side effects as if each
Dan Gohman34b3d992010-04-28 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 Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2577
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2578<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2579entry:
2580 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 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 Lattnerfbe910e2011-11-27 06:56:53 +0000[diff] [blame]2588 store volatile i32 %trap, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2589
2590 %narrowaddr = bitcast i32* @g to i16*
2591 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky64f9fb12011-05-16 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 Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2594
Nick Lewycky64f9fb12011-05-16 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 Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2597
2598true:
Chris Lattnerfbe910e2011-11-27 06:56:53 +0000[diff] [blame]2599 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2600 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 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 Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2607 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2608
Chris Lattnerfbe910e2011-11-27 06:56:53 +0000[diff] [blame]2609 store volatile i32 0, i32* @g ; This would depend on the store in %true
Dan Gohmanca4cac42011-04-12 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 Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2613 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanca4cac42011-04-12 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 Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2619 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2620
2621second_end:
Chris Lattnerfbe910e2011-11-27 06:56:53 +0000[diff] [blame]2622 store volatile i32 0, i32* @g ; This time, the instruction always depends
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2623 ; on the store in %end. Also, it is
2624 ; control-equivalent to %end, so this is
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2625 ; well-defined (again, ignoring earlier
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2626 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2627</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2628
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2629</div>
2630
2631<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2632<h3>
2633 <a name="blockaddress">Addresses of Basic Blocks</a>
2634</h3>
2635
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2636<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2637
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2638<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2639
2640<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2641 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2642 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2643
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2644<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2653
Bill Wendling1b383ba2010-10-27 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 Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2656
2657</div>
2658
2659
2660<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2661<h3>
2662 <a name="constantexprs">Constant Expressions</a>
2663</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2664
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2665<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2666
2667<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 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 Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2671 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2672
2673<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2674 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2677
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2678 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2679 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2680 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2681
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2682 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2683 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2684 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2685
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2686 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2690
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2691 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2695
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2696 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2697 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2702
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2703 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2704 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2709
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2710 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2711 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2716
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2717 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2718 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2723
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2724 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2725 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 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 Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2729
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2730 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 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 Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2735
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2736 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2740
Dan Gohman3dfb3cf2010-05-28 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2743 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2747
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2748 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2749 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2750
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2751 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2752 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2753
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2754 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2755 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2756
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2757 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2758 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2759 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2760
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2761 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2762 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2763 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2764
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2765 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2766 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2767 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2768
Nick Lewycky9e130ce2010-05-29 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 Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2781 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2787</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2788
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2789</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2791</div>
2792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2793<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2794<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2795<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2796<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2797<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2798<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2799<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2800</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2801
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2802<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2803
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2804<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2805 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 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 Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2808 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 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 Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2812
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2813<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2814i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2815</pre>
2816
Bill Wendlinge910b4c2009-07-20 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 Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2820
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2821<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2822%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2823</pre>
2824
Bill Wendlinge910b4c2009-07-20 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 Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2828
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2829<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2830call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2831</pre>
2832
Dale Johannesen8ba2d5b2009-10-21 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 Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2839
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2840<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2841call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2842</pre>
Dale Johannesen09fed252009-10-13 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 Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2847<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2848<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 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 Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2852 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2853
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2854<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2855<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2856 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2857</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2858
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2859<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2860
Bill Wendlingaee0f452011-11-30 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 Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2868
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2869<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2870call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2871...
2872!42 = !{ i32 1234567 }
2873</pre>
Chris Lattnercf9a4152010-04-07 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 Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2876 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2877 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2878
2879</div>
2880
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2881</div>
2882
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2883<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2884<h3>
2885 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2886</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2887
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2888<div>
Chris Lattnere6a5ddd2010-01-15 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 Wendlingf6cc4c22011-11-30 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 Lattnere6a5ddd2010-01-15 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 Wendlingf6cc4c22011-11-30 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 Lattnere6a5ddd2010-01-15 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 Wendlingf6cc4c22011-11-30 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 Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2922
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2923<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2924 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2925
Bill Wendling9ff5de92011-03-02 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 Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2931
2932<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2933 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2934 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2935
Bill Wendling9ff5de92011-03-02 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 Collingbourne249d9532011-10-27 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 Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2945<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 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 Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2990<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 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 Wendling0656e252011-11-09 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 Collingbourne999f90b2011-10-27 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 Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3023</div>
3024
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3025</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3026
3027<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3028<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3029 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3030</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3031<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3032<div>
Chris Lattner857755c2009-07-20 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 Lattner401e10c2009-07-20 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 Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3038
3039<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3040<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3041<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3042</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3043
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3044<div>
Chris Lattner857755c2009-07-20 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 Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3051<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3052<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3053@X = global i8 4
3054@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3055
Bill Wendling9ae75632011-11-08 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 Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3060</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3061</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3062
3063<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling9ae75632011-11-08 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 Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3070
3071<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3072 object file to prevent the assembler and linker from molesting the
3073 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3074
3075</div>
3076
3077<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 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 Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3083
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3084<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3085
3086<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 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 Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3091
3092<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3093 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3094
3095</div>
3096
3097<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3098<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3099<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3100</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3101
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3102<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3103
3104<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3105<pre>
3106%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3107@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3108</pre>
Bill Wendling9ae75632011-11-08 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 Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3116
3117</div>
3118
3119<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3120<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3121<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3122</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3123
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3124<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3125
3126<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3127<pre>
3128%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3129@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3130</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3131</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3132
Bill Wendling9ae75632011-11-08 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 Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3137
3138</div>
3139
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3140</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3141
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3142<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3143<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3144<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3145
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3146<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3147
Bill Wendlinge910b4c2009-07-20 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3154
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3155<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3156<h3>
3157 <a name="terminators">Terminator Instructions</a>
3158</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3159
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3160<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3161
Bill Wendlinge910b4c2009-07-20 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 Lattner6445ecb2011-08-02 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 Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3178
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3179<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3180<h4>
3181 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3182</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3183
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3184<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3185
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3186<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 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 Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3189 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3190</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3191
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3192<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3204
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3222<pre>
3223 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3224 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3226</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3227
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3228</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3229<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3230<h4>
3231 <a name="i_br">'<tt>br</tt>' Instruction</a>
3232</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3233
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3234<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3236<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237<pre>
Bill Wendlingb3aa4712011-07-26 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3240</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3242<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3248<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3254<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3255<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3260<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3271</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3272
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3273<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3274<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3275 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3276</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3277
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3278<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3279
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3285<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3286<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlinge910b4c2009-07-20 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 Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3291<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3292<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 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 Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3297<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3298<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 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 Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3301 transferred to the corresponding destination; otherwise, control flow is
3302 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3303
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3304<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3305<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 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 Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3309
3310<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3311<pre>
3312 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3313 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3314 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3315
3316 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3317 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3318
3319 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3323</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3325</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3326
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3327
3328<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3329<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3330 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3331</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3332
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3333<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3334
3335<h5>Syntax:</h5>
3336<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3337 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3338</pre>
3339
3340<h5>Overview:</h5>
3341
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3342<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3343 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 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 Lattnerf9be95f2009-10-27 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3353
Chris Lattnerf9be95f2009-10-27 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 Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3370 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3371</pre>
3372
3373</div>
3374
3375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3376<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3377<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3378 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3379</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3380
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3381<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3383<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3384<pre>
Devang Patel307e8ab2008-10-07 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 Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]3386 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3387</pre>
3388
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3389<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3390<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3398
Bill Wendlingf78faf82011-08-02 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3411<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3412
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3413<ol>
Bill Wendlinge910b4c2009-07-20 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 Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3417
3418 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 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 Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3421
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3422 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3426
3427 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3429
3430 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3435
3436 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3437 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3438
3439 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3441
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3442 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3445</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3446
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3447<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3452
3453<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 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 Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3457
Bill Wendlinge910b4c2009-07-20 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 Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3462
Chris Lattnerdf7a6802010-01-15 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3466<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3467<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3468 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3469 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3470 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3471 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3472</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3473
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3475
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3476<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3477
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3478<h4>
3479 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3480</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3481
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3482<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3483
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3484<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3485<pre>
3486 unwind
3487</pre>
3488
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3489<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3490<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 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 Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3494
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3495<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3496<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 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 Lattnerdf7a6802010-01-15 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3506</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3507
Bill Wendlingdccc03b2011-07-31 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 Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3526<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 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 Wendlingdccc03b2011-07-31 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 Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3533 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3534
3535<h5>Example:</h5>
3536<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3537 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3538</pre>
3539
3540</div>
3541
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3542<!-- _______________________________________________________________________ -->
3543
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3544<h4>
3545 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3546</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3547
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3548<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3549
3550<h5>Syntax:</h5>
3551<pre>
3552 unreachable
3553</pre>
3554
3555<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3556<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 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 Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3560
3561<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3562<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3563
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3564</div>
3565
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3566</div>
3567
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3568<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3569<h3>
3570 <a name="binaryops">Binary Operations</a>
3571</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3572
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3573<div>
Bill Wendlinge910b4c2009-07-20 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3581<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3582
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3583<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3584<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3585 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3586</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3587
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3588<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3590<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3591<pre>
Dan Gohmancbb38f22009-07-20 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 Gohmanfdfca792009-09-02 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3596</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3597
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3598<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3599<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3601<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3606<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3607<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3608
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3611
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3614
Dan Gohman08d012e2009-07-22 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 Gohmanfff6c532010-04-22 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 Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3620
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3621<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3622<pre>
3623 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3624</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3626</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3628<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3629<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3630 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3631</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3632
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3633<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3634
3635<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 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 Gohmanae3a0be2009-06-04 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3644<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3647
3648<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 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 Gohmanae3a0be2009-06-04 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3655
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3656</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3657
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3658<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3659<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3660 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3661</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3662
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3663<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3665<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3666<pre>
Dan Gohman08d012e2009-07-22 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 Gohmanfdfca792009-09-02 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3671</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3672
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3673<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3674<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3675 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3676
3677<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678 '<tt>neg</tt>' instruction present in most other intermediate
3679 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3680
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3681<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3686<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3687<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3688
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3689<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3692
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3695
Dan Gohman08d012e2009-07-22 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 Gohmanfff6c532010-04-22 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 Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3701
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3702<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3703<pre>
3704 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3705 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3706</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3707
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3708</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3709
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3710<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3711<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3712 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3713</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3714
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3715<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3716
3717<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3723<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3725
3726<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3727 '<tt>fneg</tt>' instruction present in most other intermediate
3728 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3729
3730<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3731<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3734
3735<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3743
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3744</div>
3745
3746<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3747<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3748 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3749</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3750
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3751<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3753<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3754<pre>
Dan Gohman08d012e2009-07-22 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 Gohmanfdfca792009-09-02 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3759</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3760
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3761<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3764<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3768
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3769<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3770<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3771
Bill Wendlinge910b4c2009-07-20 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 Gohman08d012e2009-07-22 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 Gohmanfff6c532010-04-22 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 Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3789<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3790<pre>
3791 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3792</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3794</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3795
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3796<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3797<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3798 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3799</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3800
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3801<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3802
3803<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3806</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3807
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3808<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3809<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3810
3811<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3812<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3815
3816<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 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 Wendlinge910b4c2009-07-20 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 Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3822</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3824</div>
3825
3826<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3827<h4>
3828 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3829</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3830
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3831<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3832
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3833<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834<pre>
Chris Lattner35bda892011-02-06 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 Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3837</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3839<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3840<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3841
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3842<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3843<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3846
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3847<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3848<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3849
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3850<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3851 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3852
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3853<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3854
Chris Lattner35bda892011-02-06 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 Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3860<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3861<pre>
3862 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3863</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3864
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3865</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3866
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3867<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3868<h4>
3869 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3870</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3871
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3872<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3873
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3874<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3875<pre>
Dan Gohmancbb38f22009-07-20 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 Gohmanfdfca792009-09-02 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 Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3878</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3879
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3881<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3882
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3883<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3884<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3887
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3888<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3892<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3894
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3895<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 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 Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3899<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3900 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3901 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3902
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3903<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3904<pre>
3905 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3906</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3907
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3908</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3910<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3911<h4>
3912 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3913</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3915<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3918<pre>
Gabor Greiffb224a22008-08-07 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3920</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3921
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3924
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3925<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3926<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3929
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3930<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3931<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3932
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3933<h5>Example:</h5>
Chris Lattner5568e942008-05-20 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3936</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3937
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3938</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3939
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3940<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3941<h4>
3942 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3943</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3945<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3946
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3947<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3950</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3956<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3957<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Spencer0a783f72006-11-02 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3963 This instruction always performs an unsigned division to get the
3964 remainder.</p>
3965
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3966<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3968
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3969<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3970
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3971<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972<pre>
3973 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3974</pre>
3975
3976</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3978<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3979<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3980 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3981</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3982
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3983<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3984
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3985<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3986<pre>
Gabor Greiffb224a22008-08-07 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3988</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3989
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3990<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3995
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3996<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3997<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4000
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4001<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4002<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 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 Wendlinge910b4c2009-07-20 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 Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4012<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4013 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4014
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4015<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4022<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023<pre>
4024 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4025</pre>
4026
4027</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4029<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4030<h4>
4031 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4032</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4033
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4034<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4035
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4036<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4039</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4045<h5>Arguments:</h5>
4046<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4049
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4050<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4053
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4054<h5>Example:</h5>
Chris Lattner5568e942008-05-20 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 Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4057</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4058
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4059</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4060
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4061</div>
4062
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4063<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4064<h3>
4065 <a name="bitwiseops">Bitwise Binary Operations</a>
4066</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4067
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4068<div>
Bill Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4076<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4077<h4>
4078 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4079</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4080
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4081<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4082
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4083<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084<pre>
Chris Lattnerf067d582011-02-07 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4089</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4090
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4091<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4094
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4095<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4099
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4100<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4107
Chris Lattnerf067d582011-02-07 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 Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4110 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4116<h5>Example:</h5>
4117<pre>
Reid Spencer569f2fa2007-01-31 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 Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4121 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4123</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4125</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4126
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4127<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4128<h4>
4129 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4130</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4132<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4134<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4135<pre>
Chris Lattnerf067d582011-02-07 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4138</pre>
4139
4140<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4143
4144<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4145<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 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 Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4156
Chris Lattnerf067d582011-02-07 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 Spencer569f2fa2007-01-31 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 Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4168 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4170</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4171
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4172</div>
4173
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4174<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4175<h4>
4176 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4177</h4>
4178
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4179<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4180
4181<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182<pre>
Chris Lattnerf067d582011-02-07 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4185</pre>
4186
4187<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4191
4192<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4193<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4196
4197<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4204
Chris Lattnerf067d582011-02-07 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 Spencer569f2fa2007-01-31 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 Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4215 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 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 Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4217</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4218
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4219</div>
4220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4221<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4222<h4>
4223 <a name="i_and">'<tt>and</tt>' Instruction</a>
4224</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4225
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4226<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4227
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4228<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4229<pre>
Gabor Greiffb224a22008-08-07 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4231</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4236
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4237<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4238<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4242<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4243<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4245<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4275<h5>Example:</h5>
Chris Lattner5568e942008-05-20 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 Spencerca86e162006-12-31 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4280</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4281</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4282<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4283<h4>
4284 <a name="i_or">'<tt>or</tt>' Instruction</a>
4285</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4287<div>
Bill Wendlinge910b4c2009-07-20 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4299<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4303<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4304<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4305
Chris Lattner261efe92003-11-25 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4336<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4337<pre>
4338 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4341</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4342
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4343</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4344
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4345<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4346<h4>
4347 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4348</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4349
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4350<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4352<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4355</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4356
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4357<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4362<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4363<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4366
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4367<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4368<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369
Chris Lattner261efe92003-11-25 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4400<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4401<pre>
4402 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4406</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4407
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4408</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4409
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4410</div>
4411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4412<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4413<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4414 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4415</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4416
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4417<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4418
4419<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4425
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4426<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4427<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4428 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4429</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4431<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4432
4433<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4434<pre>
Reid Spencerca86e162006-12-31 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4436</pre>
4437
4438<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4441
4442
4443<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4448
4449<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4454
4455<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4456<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4457 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4458</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4459
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4460</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4461
4462<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4463<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4464 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4465</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4466
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4467<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4468
4469<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4470<pre>
Dan Gohmanf3480b92008-05-12 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4472</pre>
4473
4474<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4477
4478<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4484
4485<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4490
4491<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4492<pre>
Gabor Greifa5b6f452009-10-28 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4494</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4495
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4496</div>
4497
4498<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4499<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4500 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4501</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4502
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4503<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4504
4505<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4506<pre>
Mon P Wangaeb06d22008-11-10 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4508</pre>
4509
4510<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4514
4515<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4521
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4524
4525<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4531
4532<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4533<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4534 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4536 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerca86e162006-12-31 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 Christopher6c7e8a02009-12-05 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 Wangaeb06d22008-11-10 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 Christopher6c7e8a02009-12-05 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 Wangaeb06d22008-11-10 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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4542</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4544</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4545
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4546</div>
4547
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4548<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4549<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4550 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4551</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4552
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4553<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4554
Chris Lattnerfdfeb692010-02-12 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4557
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4558<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4559<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4560 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4561</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4562
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4563<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4564
4565<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 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 Lattnerfdfeb692010-02-12 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4573
4574<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4576 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4588
4589<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4592
4593<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4594<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4595 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4596</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4597
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4598</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4599
4600<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4601<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4602 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4603</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4604
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4605<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4606
4607<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4608<pre>
Bill Wendling194229e2011-07-26 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4610</pre>
4611
4612<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4615
4616<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4617<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4618 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 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 Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4622 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4625
4626<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4630
4631<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4632<pre>
Chris Lattner8645d1a2011-05-22 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 Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4636</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4637
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4638</div>
4639
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4640</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4641
4642<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4643<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4644 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4645</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4646
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4647<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4648
Bill Wendlinge910b4c2009-07-20 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 Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4651 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4652 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4653
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4654<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4655<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4656 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4657</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4658
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4659<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4660
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4661<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4662<pre>
Dan Gohmanf75a7d32010-05-28 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4664</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4665
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4666<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4667<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4671
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4672<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4682
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4683<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4685<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4686<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 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 Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4695<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4696<pre>
Dan Gohman81e21672009-01-04 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 Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4701</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4702
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4703</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4704
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4705<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4706<h4>
4707 <a name="i_load">'<tt>load</tt>' Instruction</a>
4708</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4710<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4711
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4712<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713<pre>
Eli Friedmanf03bb262011-08-12 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 Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4716 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717</pre>
4718
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4719<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4720<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4722<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Yasskin93e066d2010-04-26 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729
Eli Friedman21006d42011-08-09 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 Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4743<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4745 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 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 Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4748 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4749 produce less efficient code. An alignment of 1 is always safe.</p>
4750
Bill Wendling7c78dbb2010-02-25 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 Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4753 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 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 Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4757 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4758
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4759<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4768<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4772 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4773</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4774
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4775</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4777<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4778<h4>
4779 <a name="i_store">'<tt>store</tt>' Instruction</a>
4780</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4782<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4783
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4784<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4785<pre>
Eli Friedmanf03bb262011-08-12 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 Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4788</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4790<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4791<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4792
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4793<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Yasskin93e066d2010-04-26 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802
Eli Friedman21006d42011-08-09 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 Wendlinge910b4c2009-07-20 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 Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4824<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4825 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4826 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 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 Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4830 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4831
4832
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4833<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4843<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4844<pre>
4845 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 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 Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4848</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4849
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4850</div>
4851
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4852<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4853<h4>
4854<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4855</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4856
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4857<div>
Eli Friedman47f35132011-07-25 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 Friedman47f35132011-07-25 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 Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4908<h4>
4909<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4910</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4911
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4912<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4913
4914<h5>Syntax:</h5>
4915<pre>
Eli Friedmanf03bb262011-08-12 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 Friedmanff030482011-07-28 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 Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4991<h4>
4992<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4993</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4994
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4995<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4996
4997<h5>Syntax:</h5>
4998<pre>
Eli Friedmanf03bb262011-08-12 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 Friedmanff030482011-07-28 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 Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5062<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5063 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5064</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5065
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5066<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5067
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5068<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5069<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5070 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5072</pre>
5073
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5074<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5075<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5078
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5079<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5080<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5081 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 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 Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5087 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5088 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5089 can never be pointers, since that would require loading the pointer before
5090 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5091
5092<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5093 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 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 Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5096 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5097
Bill Wendlinge910b4c2009-07-20 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5100
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5101<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5102struct RT {
5103 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5104 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5105 char C;
5106};
5107struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5108 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5109 double Y;
5110 struct RT Z;
5111};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5112
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5113int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5114 return &amp;s[1].Z.B[5][13];
5115}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5116</pre>
5117
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5118<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5119
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5120<pre class="doc_code">
Chris Lattnere7886e42009-01-11 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5123
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5124define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5129</pre>
5130
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5131<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5132<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlinge910b4c2009-07-20 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5141
Bill Wendlinge910b4c2009-07-20 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5145
5146<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]5147 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5148 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 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 Spencerca86e162006-12-31 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 Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5154 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5155</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5156
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5157<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 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 Friedman266246c2011-08-12 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 Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5166
5167<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedman266246c2011-08-12 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 Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5176
Bill Wendlinge910b4c2009-07-20 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 Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5179
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5180<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5181<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5182 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 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 Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5185 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5186 <i>; yields i8*:eptr</i>
5187 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5188 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5189 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5190</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5191
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5192</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5193
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5194</div>
5195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5196<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5197<h3>
5198 <a name="convertops">Conversion Operations</a>
5199</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5201<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5202
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5203<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 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 Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5207<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5208<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5209 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5210</h4>
5211
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5212<div>
Reid Spencer9dee3ac2006-11-08 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 Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5222
5223<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5230
5231<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5236
5237<h5>Example:</h5>
5238<pre>
Nadav Rotem8c20ec52011-02-24 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5243</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5244
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5245</div>
5246
5247<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5248<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5249 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5250</h4>
5251
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5252<div>
Reid Spencer9dee3ac2006-11-08 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5260<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5261 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5262
5263
5264<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5270 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5274 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5275
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5276<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5277
5278<h5>Example:</h5>
5279<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5280 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5281 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5283</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5284
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5285</div>
5286
5287<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5288<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5289 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5290</h4>
5291
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5292<div>
Reid Spencer9dee3ac2006-11-08 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 Rotem8c20ec52011-02-24 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5308 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5309
5310<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5314
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5315<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5316
5317<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5318<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5319 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5320 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5322</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5323
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5324</div>
5325
5326<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5327<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5328 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5329</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5330
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5331<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5332
5333<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5340 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 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 Wendlinge910b4c2009-07-20 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 Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5346 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5347 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5348
5349<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5350<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5351 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 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 Spencer3fa91b02006-11-09 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5361
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5362</div>
5363
5364<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5365<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5366 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5367</h4>
5368
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5369<div>
Reid Spencer9dee3ac2006-11-08 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5378 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5379
5380<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5381<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5385
5386<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5387<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5392
5393<h5>Example:</h5>
5394<pre>
Nick Lewycky5bb3ece2011-03-31 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5397</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5398
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5399</div>
5400
5401<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5402<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5403 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5404</h4>
5405
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5406<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5407
5408<h5>Syntax:</h5>
5409<pre>
Reid Spencer1539a1c2007-07-31 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5411</pre>
5412
5413<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5414<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5415 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5416
5417<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5423
5424<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5425<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5429
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5430<h5>Example:</h5>
5431<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5432 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5433 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5434 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5435</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5436
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5437</div>
5438
5439<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5440<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5441 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5442</h4>
5443
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5444<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5445
5446<h5>Syntax:</h5>
5447<pre>
Reid Spencerd4448792006-11-09 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5449</pre>
5450
5451<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5452<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5455
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5456<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5462
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5463<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5464<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5468
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5469<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5470<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5471 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5472 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5473 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5474</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5475
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5476</div>
5477
5478<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5479<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5480 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5481</h4>
5482
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5483<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5484
5485<h5>Syntax:</h5>
5486<pre>
Reid Spencerd4448792006-11-09 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5488</pre>
5489
5490<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5491<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5492 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5493
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5494<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5495<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5500
5501<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5502<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5506
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5507<h5>Example:</h5>
5508<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5509 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5510 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5511</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5512
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5513</div>
5514
5515<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5516<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5517 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5518</h4>
5519
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5520<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5521
5522<h5>Syntax:</h5>
5523<pre>
Reid Spencerd4448792006-11-09 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5525</pre>
5526
5527<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5530
5531<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5532<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5537
5538<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5542
5543<h5>Example:</h5>
5544<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5545 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5546 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5547</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5548
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5549</div>
5550
5551<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5552<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5553 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5554</h4>
5555
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5556<div>
Reid Spencer72679252006-11-11 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 Wendlinge910b4c2009-07-20 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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5566
5567<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer72679252006-11-11 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 Wendlinge910b4c2009-07-20 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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5580
5581<h5>Example:</h5>
5582<pre>
Jeff Cohenb627eab2007-04-29 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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5585</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5586
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5587</div>
5588
5589<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5590<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5591 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5592</h4>
5593
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5594<div>
Reid Spencer72679252006-11-11 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 Wendlinge910b4c2009-07-20 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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5604
5605<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5606<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 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 Spencer72679252006-11-11 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 Wendlinge910b4c2009-07-20 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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5617
5618<h5>Example:</h5>
5619<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5620 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif6a292012009-10-28 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 Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5623</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5624
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5625</div>
5626
5627<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5628<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5629 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5630</h4>
5631
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5632<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5633
5634<h5>Syntax:</h5>
5635<pre>
Reid Spencer5c0ef472006-11-11 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5637</pre>
5638
5639<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5640<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5641 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5642
5643<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5652
5653<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5654<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 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 Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5661
5662<h5>Example:</h5>
5663<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5664 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5665 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5666 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5667</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5669</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5670
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5671</div>
5672
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5673<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5674<h3>
5675 <a name="otherops">Other Operations</a>
5676</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5678<div>
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5683<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5684<h4>
5685 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5686</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5687
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5688<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5689
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5690<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5693</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5694
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5695<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 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 Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5717
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5718<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5722<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5725 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5726 result, as follows:</p>
5727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5728<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5729 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5730 <tt>false</tt> otherwise. No sign interpretation is necessary or
5731 performed.</li>
5732
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5733 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5734 <tt>false</tt> otherwise. No sign interpretation is necessary or
5735 performed.</li>
5736
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5737 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5738 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5739
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5740 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5744 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5746
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5747 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5750 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5751 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5752
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5753 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5757 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5758 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5759
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5760 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5762</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5763
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5764<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5770
5771<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772<pre>
5773 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5779</pre>
Dan Gohmanc766f722009-01-22 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5784</div>
5785
5786<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5787<h4>
5788 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5789</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5791<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5792
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5793<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5796</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5797
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5798<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5803(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 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 Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5814<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5815 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 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 Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5830 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5831</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5832
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5833<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5841<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5842<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 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 Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5845 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846 follows:</p>
5847
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5848<ol>
5849 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5850
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5851 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5852 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5853
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5854 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5855 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5857 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5858 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5859
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5860 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5861 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5862
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5863 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5864 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5865
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5866 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5867 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5868
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5869 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5870
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5871 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5872 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5873
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5874 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5875 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5876
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5877 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5878 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5879
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5880 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5881 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5882
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5883 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5885
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5886 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5887 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5888
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5889 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5890
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5891 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5892</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5893
5894<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohmanf72fb672008-09-09 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5900</pre>
Dan Gohmanc766f722009-01-22 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 Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5905</div>
5906
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5907<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5908<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5909 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5910</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5911
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5912<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5913
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5914<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5918
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5919<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5923<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5930
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5934
Bill Wendlinge910b4c2009-07-20 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 Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5939
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5940<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5941<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 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 Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5944
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5945<h5>Example:</h5>
Chris Lattner5568e942008-05-20 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5952
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5953</div>
5954
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5956<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5957 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5958</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5959
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5960<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5961
5962<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5963<pre>
Dan Gohmanf72fb672008-09-09 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 Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5966 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5967</pre>
5968
5969<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5972
5973
5974<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5980
5981<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5984
Bill Wendlinge910b4c2009-07-20 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5987
5988<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5989<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5990 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5991</pre>
Dan Gohmanc766f722009-01-22 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 Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5996</div>
5997
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5998<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5999<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6000 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6001</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6002
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6003<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6004
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6005<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6006<pre>
Devang Patel307e8ab2008-10-07 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 Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6008</pre>
6009
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6010<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6011<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6012
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6013<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6014<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6015
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6016<ol>
Jeffrey Yasskin95fa80a2010-01-09 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 Chengdc444e92010-03-08 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 Yasskin95fa80a2010-01-09 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 Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6034 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 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 Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6039
Bill Wendlinge910b4c2009-07-20 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 Yasskin95fa80a2010-01-09 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 Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6045
Bill Wendlinge910b4c2009-07-20 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 Lattner0724fbd2010-03-02 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 Wendlinge910b4c2009-07-20 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 Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6073</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6074
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6075<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6082
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6083<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6084<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6085 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6086 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 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 Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6090
6091 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6092 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 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 Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6095 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6096 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6097</pre>
6098
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6099<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 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 Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6103freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6104
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6105</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6106
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6107<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6108<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6109 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6110</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6111
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6112<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6113
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6114<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6115<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6116 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6117</pre>
6118
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6119<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6120<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 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 Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6123
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6124<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6129
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6130<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnere19d7a72004-09-27 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6138 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6139
Bill Wendlinge910b4c2009-07-20 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 Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6143
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6144<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6145<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6146
Bill Wendlinge910b4c2009-07-20 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 Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6150
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6151</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6152
Bill Wendlingf78faf82011-08-02 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 Wendlingbf13ee12011-08-08 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 Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6165 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6166 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 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 Wendlinge6e88262011-08-12 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 Wendlingf78faf82011-08-02 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 Wendlingb7a01352011-08-03 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 Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6201 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6202
Bill Wendlingf78faf82011-08-02 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 Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6225 cleanup
Bill Wendlingf78faf82011-08-02 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 Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6229 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6230</pre>
6231
6232</div>
6233
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6234</div>
6235
6236</div>
6237
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6238<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6239<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6240<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6241
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6242<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6243
6244<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6250
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6251<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6259
Bill Wendlinge910b4c2009-07-20 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6270
Bill Wendlinge910b4c2009-07-20 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 Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6281
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6282<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6283 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6284
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6285<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6286<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6287 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6288</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6289
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6290<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6291
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6296
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6301
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6302<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6303 instruction and the variable argument handling intrinsic functions are
6304 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6305
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6306<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6307define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6308 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6309 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6310 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6311 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6312
6313 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6314 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6315
6316 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6317 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6318 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6319 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6320 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6321
6322 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6323 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6324 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6325}
Anton Korobeynikov5d522f32007-03-21 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6330</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6331
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6332<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6333<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6334 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6335</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6336
6337
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6338<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6339
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6340<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6341<pre>
6342 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6343</pre>
6344
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6345<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6348
6349<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6350<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6351
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6352<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6353<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlinge910b4c2009-07-20 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 Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6361</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6362
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6363<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6364<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6365 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6366</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6367
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6368<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6369
Bill Wendlinge910b4c2009-07-20 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 Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6376<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 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 Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6380
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6381<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6382<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6383
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6384<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6385<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlinge910b4c2009-07-20 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 Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6391
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6392</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6393
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6394<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6395<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6396 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6397</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6398
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6399<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6400
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6401<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6402<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6403 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6404</pre>
6405
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6406<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6407<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6409
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6410<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6411<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6414
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6415<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6416<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6422
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6423</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6424
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6425</div>
6426
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6427<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6428<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6429 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6430</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6431
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6432<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6433
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6434<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6435Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 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 Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6443
Bill Wendlinge910b4c2009-07-20 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 Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6446
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6447<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6448<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6449 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6450</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6451
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6452<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6453
6454<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6455<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6456 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6457</pre>
6458
6459<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6460<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6461 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6462
6463<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6464<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6468
6469<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6470<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6475
6476</div>
6477
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6478<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6479<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6480 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6481</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6482
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6483<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6484
6485<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6486<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6487 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6488</pre>
6489
6490<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6491<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6492 locations, allowing garbage collector implementations that require read
6493 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6494
6495<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6496<p>The second argument is the address to read from, which should be an address
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6500
6501<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6502<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6507
6508</div>
6509
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6510<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6511<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6512 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6513</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6514
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6515<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6516
6517<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6518<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6519 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6520</pre>
6521
6522<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6523<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6526
6527<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6528<p>The first argument is the reference to store, the second is the start of the
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6532
6533<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6534<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 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 Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6539
6540</div>
6541
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6542</div>
6543
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6544<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6545<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6546 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6547</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6548
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6549<div>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6553
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6554<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6555<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6556 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6557</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6558
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6559<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6560
6561<h5>Syntax:</h5>
6562<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6563 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6564</pre>
6565
6566<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6570
6571<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6575
6576<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6582
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6586
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6587</div>
6588
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6589<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6590<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6591 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6592</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6593
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6594<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6595
6596<h5>Syntax:</h5>
6597<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6598 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6599</pre>
6600
6601<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6604
6605<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6609
6610<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6616
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6620
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6621</div>
6622
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6623<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6624<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6625 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6626</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6627
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6628<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6629
6630<h5>Syntax:</h5>
6631<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6632 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6633</pre>
6634
6635<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6650
6651</div>
6652
6653<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6654<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6655 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6656</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6657
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6658<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6659
6660<h5>Syntax:</h5>
6661<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6662 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6663</pre>
6664
6665<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6671
6672<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6673<p>See the description
6674 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6675
6676</div>
6677
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6678<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6679<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6680 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6681</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6682
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6683<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6684
6685<h5>Syntax:</h5>
6686<pre>
Bruno Cardoso Lopes9a767332011-06-14 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 Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6688</pre>
6689
6690<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6695
6696<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lopes9a767332011-06-14 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 Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6704
6705<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6710
6711</div>
6712
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6713<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6714<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6715 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6716</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6718<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6719
6720<h5>Syntax:</h5>
6721<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6722 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6723</pre>
6724
6725<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6734
6735<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6736<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6737
6738<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6739<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6740 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6741
6742</div>
6743
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6744<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6745<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6746 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6747</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6748
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6749<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6750
6751<h5>Syntax:</h5>
6752<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6753 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6754</pre>
6755
6756<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6762
6763<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6768
6769</div>
6770
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6771</div>
6772
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6773<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6774<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6775 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6776</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6777
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6778<div>
Bill Wendlinge910b4c2009-07-20 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6784
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6785<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6786<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6787 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6788</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6789
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6790<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6791
6792<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6793<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wange88909b2010-04-07 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6796
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6797<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6798 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6799 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6800 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6801 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6802</pre>
6803
6804<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6808<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6811
6812<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6813
Bill Wendlinge910b4c2009-07-20 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 Lattner9f636de2010-04-08 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6819
Dan Gohmanb55a1ee2010-03-01 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 Wendlinge910b4c2009-07-20 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 Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6823
Jeffrey Yasskin93e066d2010-04-26 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 Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6828
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6829<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6830
Bill Wendlinge910b4c2009-07-20 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 Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6836
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6837</div>
6838
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6839<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6840<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6841 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6842</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6843
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6844<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6845
6846<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6847<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6848 width and for different address space. Not all targets support all bit
6849 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6850
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6851<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6852 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6853 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6854 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6855 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6856</pre>
6857
6858<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6864<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 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 Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6867
6868<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6869
Bill Wendlinge910b4c2009-07-20 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 Lattner9f636de2010-04-08 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 Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6875
Dan Gohmanb55a1ee2010-03-01 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 Wendlinge910b4c2009-07-20 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 Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6879
Jeffrey Yasskin93e066d2010-04-26 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 Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6884
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6885<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6886
Bill Wendlinge910b4c2009-07-20 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 Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6892
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6893</div>
6894
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6895<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6896<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6897 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6898</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6899
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6900<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6901
6902<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6903<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6904 width and for different address spaces. However, not all targets support all
6905 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6906
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6907<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6908 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6909 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6910 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6911 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6912</pre>
6913
6914<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6917
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6918<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6921
6922<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6923<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6924 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6925 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6926 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6927
Dan Gohmanb55a1ee2010-03-01 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929 then the caller guarantees that the destination pointer is aligned to that
6930 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6931
Jeffrey Yasskin93e066d2010-04-26 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 Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6936
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6937<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6942
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6943</div>
6944
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6945<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6946<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6947 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6948</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6949
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6950<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6951
6952<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6957<pre>
Dale Johannesen408f9c12007-10-02 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 Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6963</pre>
6964
6965<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6972
6973<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6974<p>The argument and return value are floating point numbers of the same
6975 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6976
6977<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6980
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6981</div>
6982
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6983<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6984<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6985 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6986</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6987
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6988<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6989
6990<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6995<pre>
Dale Johannesen408f9c12007-10-02 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 Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7001</pre>
7002
7003<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7008
7009<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7012
7013<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7016
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7017</div>
7018
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7019<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7020<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7021 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7022</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7023
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7024<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7025
7026<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7041
7042<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7043<p>The argument and return value are floating point numbers of the same
7044 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7045
7046<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7050
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7051</div>
7052
7053<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7054<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7055 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7056</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7057
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7058<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7059
7060<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7074<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7075
7076<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7077<p>The argument and return value are floating point numbers of the same
7078 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7079
7080<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7084
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7085</div>
7086
7087<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7088<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7089 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7090</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7091
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7092<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7093
7094<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 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 Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7110
7111<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7114
7115<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7119
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7120</div>
7121
Dan Gohman4e9011c2011-05-23 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 Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7186</div>
7187
7188<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 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 Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7209<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 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 Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7220</div>
7221
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7222</div>
7223
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7224<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7225<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7226 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7227</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7228
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7229<div>
Bill Wendlinge910b4c2009-07-20 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7233
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7234<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7235<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7236 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7237</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7238
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7239<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7240
7241<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7242<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7244
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7245<pre>
Chandler Carruth69940402007-08-04 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 Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7249</pre>
7250
7251<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7256
7257<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7266
7267</div>
7268
7269<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7270<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7271 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7272</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7273
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7274<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7275
7276<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7277<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Andersonf1ac4652011-07-01 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7280
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7281<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7282 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7283 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7284 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 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 Andersonf1ac4652011-07-01 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7288</pre>
7289
7290<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7293
7294<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7295<p>The only argument is the value to be counted. The argument may be of any
Owen Andersonf1ac4652011-07-01 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7298
7299<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7302
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7303</div>
7304
7305<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7306<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7307 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7308</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7309
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7310<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7311
7312<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7313<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Andersonf1ac4652011-07-01 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7316
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7317<pre>
Chandler Carruth69940402007-08-04 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 Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7320 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 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 Andersonf1ac4652011-07-01 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7324</pre>
7325
7326<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7329
7330<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7331<p>The only argument is the value to be counted. The argument may be of any
Owen Andersonf1ac4652011-07-01 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 Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7334
7335<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7336<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Andersonf1ac4652011-07-01 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7339 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7340
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7341</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7342
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7343<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7344<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7345 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7346</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7347
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7348<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7349
7350<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7351<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Andersonf1ac4652011-07-01 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7354
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7355<pre>
Chandler Carruth69940402007-08-04 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 Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7358 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 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 Andersonf1ac4652011-07-01 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 Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7362</pre>
7363
7364<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7367
7368<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7369<p>The only argument is the value to be counted. The argument may be of any
Owen Andersonf1ac4652011-07-01 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 Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7372
7373<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7374<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7377 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7378
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7379</div>
7380
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7381</div>
7382
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7383<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7384<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7385 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7386</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7387
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7388<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7389
7390<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7391
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7392<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7398
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7399<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7400
7401<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7402<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7403 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7412<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7415
7416<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7417<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7422
7423<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7424<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 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 Takumi05d02652011-04-18 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7446
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7447<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7448
7449<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7450<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7451 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7460<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7463
7464<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7465<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7470
7471<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7472<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 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 Takumi05d02652011-04-18 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7493
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7494<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7495
7496<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7497<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7498 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7507<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7510
7511<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7512<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7517
7518<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7519<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 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 Takumi05d02652011-04-18 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7541
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7542<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7543
7544<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7545<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7546 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7555<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7558
7559<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7560<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7565
7566<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7567<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 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 Takumi05d02652011-04-18 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7589
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7590<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7591
7592<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7593<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7594 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 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 Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7607
7608<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7609<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7614
7615<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7616<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendlingac1df8e2009-02-08 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 Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7630</div>
7631
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7632<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7638
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7639<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7640
7641<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7642<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7643 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7652<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7655
7656<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7657<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 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 Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7662
7663<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7664<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 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 Wendling41b485c2009-02-08 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 Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7680</div>
7681
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7682<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7683<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7684 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7685</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7686
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7687<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7688
Chris Lattner0cec9c82010-03-15 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 Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7692
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7693<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 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 Lattner0cec9c82010-03-15 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 Lattner82c3dc62010-03-14 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7701
7702<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7708
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7709<div>
Anton Korobeynikovf02e7302010-03-14 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 Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7728 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7729 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 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 Takumi05d02652011-04-18 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 Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7745
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7746<div>
Anton Korobeynikovf02e7302010-03-14 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 Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7764 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 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 Korobeynikovf02e7302010-03-14 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 Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7776</div>
7777
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7778<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7779<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7780 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7781</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7782
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7783<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7784
Bill Wendlinge910b4c2009-07-20 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 Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7791
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7792<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7793<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7794 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7795</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7796
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7797<div>
Bill Wendlinge910b4c2009-07-20 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 Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7804</div>
7805
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7806<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7807<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7808 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7809</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7811<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7812
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7813<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 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 Wendlinge910b4c2009-07-20 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 Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7827<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 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 Sands4a544a72011-09-06 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 Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7832 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7833</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7834
Dan Gohman3dfb3cf2010-05-28 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7837
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7838<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7844
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7845<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7846
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7847<h5>Syntax:</h5>
7848<pre>
Duncan Sands4a544a72011-09-06 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 Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7850</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7851
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7852<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7855
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7856<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7866<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7867<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands4a544a72011-09-06 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7912
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7913</div>
7914
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7915</div>
7916
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7917<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7918<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7919 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7920</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7921
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7922<div>
Nick Lewyckycc271862009-10-13 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 Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7927<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7928<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7929 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7930</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7931
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7932<div>
Nick Lewyckycc271862009-10-13 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 Lewycky321333e2009-10-13 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 Lewyckycc271862009-10-13 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 Lewycky8d336592009-10-27 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 Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7953 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7954
7955</div>
7956
7957<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7958<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7959 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7960</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7961
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7962<div>
Nick Lewyckycc271862009-10-13 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 Lewycky321333e2009-10-13 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 Lewyckycc271862009-10-13 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 Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7987<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7988 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7989</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7990
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7991<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7992
7993<h5>Syntax:</h5>
7994<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7995 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 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 Lewycky321333e2009-10-13 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 Lewyckycc271862009-10-13 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 Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8015<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8016 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8017</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8018
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8019<div>
Nick Lewyckycc271862009-10-13 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 Lewycky321333e2009-10-13 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 Lewyckycc271862009-10-13 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 Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8041</div>
8042
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8043<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8044<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8045 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8046</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8047
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8048<div>
Bill Wendlinge910b4c2009-07-20 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 Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8053<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8054<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8055 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8056</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8057
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8058<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8059
8060<h5>Syntax:</h5>
8061<pre>
Dan Gohman3dfb3cf2010-05-28 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 Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8063</pre>
8064
8065<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8066<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8067
8068<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8072
8073<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8076 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8077 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8078
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8079</div>
8080
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8081<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8082<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8083 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8084</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8085
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8086<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8087
8088<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8092<pre>
Dan Gohman3dfb3cf2010-05-28 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 Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8098</pre>
8099
8100<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8101<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8102
8103<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8108
8109<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8112 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8113 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8114
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8115</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8116
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8117<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8118<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8119 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8120</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8121
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8122<div>
Anton Korobeynikov4cb86182008-01-15 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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8130<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8131
8132<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8133<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8134
8135<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8139
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8140</div>
8141
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8142<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8143<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8144 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8145</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8146
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8147<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8148
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8149<h5>Syntax:</h5>
8150<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8151 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8152</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8153
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8154<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 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 Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8159<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 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 Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8165<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 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 Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8170 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 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 Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8174</div>
8175
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8176<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8177<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8178 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8179</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8180
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8181<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8182
8183<h5>Syntax:</h5>
8184<pre>
Dan Gohman3dfb3cf2010-05-28 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 Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8187</pre>
8188
8189<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 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 Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8195
8196<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8197<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8198 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 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 Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8201 1, variables are not allowed.</p>
8202
Eric Christopher0e671492009-11-30 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 Wendling1b383ba2010-10-27 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 Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8208
8209</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8210<!-- _______________________________________________________________________ -->
8211<h4>
8212 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8213</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8214
Jakub Staszakb170e2d2011-12-04 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 Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8234</div>
8235
8236</div>
8237
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8238</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8239<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8240<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8241<address>
8242 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8243 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8244 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8245 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8246
8247 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8248 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8249 Last modified: $Date$
8250</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8252</body>
8253</html>