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gerrit-public.fairphone.software / platform / external / llvm / d4347e1af9141ec9f8e3e527367bfd16c0cc4ffb / . / docs / LangRef.html
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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.">
Daniel Dunbaradea4972012-04-19 20:20:34 +0000[diff] [blame]10 <link rel="stylesheet" href="_static/llvm.css" type="text/css">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]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 Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison 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>
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]106 <li><a href="#fpmath">'<tt>fpmath</tt>' Metadata</a></li>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]107 <li><a href="#range">'<tt>range</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]108 </ol>
109 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]110 </ol>
111 </li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]112 <li><a href="#module_flags">Module Flags Metadata</a>
113 <ol>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]114 <li><a href="#objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a></li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]115 </ol>
116 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]117 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
118 <ol>
119 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]120 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
121 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]122 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
123 Global Variable</a></li>
124 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
125 Global Variable</a></li>
126 </ol>
127 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#instref">Instruction Reference</a>
129 <ol>
130 <li><a href="#terminators">Terminator Instructions</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
133 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]134 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]135 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]136 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]137 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]138 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]139 </ol>
140 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]141 <li><a href="#binaryops">Binary Operations</a>
142 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]144 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]146 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]147 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]148 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]149 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
150 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
151 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]152 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
153 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
154 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]157 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
158 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]159 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
160 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
161 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]162 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]163 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]164 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 <li><a href="#vectorops">Vector Operations</a>
168 <ol>
169 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
170 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
171 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]172 </ol>
173 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]174 <li><a href="#aggregateops">Aggregate Operations</a>
175 <ol>
176 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
177 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
178 </ol>
179 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]180 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]181 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]182 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
183 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
184 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
185 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
186 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
187 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]188 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 </ol>
190 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]191 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]192 <ol>
193 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
194 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
195 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
196 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]198 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
199 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
200 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
201 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]202 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
203 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]204 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]205 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]206 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]207 <li><a href="#otherops">Other Operations</a>
208 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]209 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
210 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]212 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]214 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]215 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]218 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]219 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]220 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]221 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
223 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
225 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
226 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227 </ol>
228 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
230 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]231 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
232 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
233 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]234 </ol>
235 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]236 <li><a href="#int_codegen">Code Generator Intrinsics</a>
237 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]238 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
239 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
240 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
241 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
242 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
243 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]244 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]245 </ol>
246 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]247 <li><a href="#int_libc">Standard C Library Intrinsics</a>
248 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]249 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
252 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]254 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
255 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]257 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
258 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]259 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]260 </ol>
261 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]262 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]264 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]265 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
266 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
267 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]268 </ol>
269 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]270 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
271 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]272 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
273 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
274 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
275 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
276 <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]277 <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]278 </ol>
279 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]280 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
281 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]282 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
283 <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]284 </ol>
285 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]286 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]287 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]288 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]289 <ol>
290 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]291 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]292 </ol>
293 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]294 <li><a href="#int_memorymarkers">Memory Use Markers</a>
295 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]296 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
297 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
298 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
299 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]300 </ol>
301 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]303 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]304 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]306 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]308 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]309 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame^]310 <li><a href="#int_debugger">
311 '<tt>llvm.debugger</tt>' Intrinsic</a></li>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]312 <li><a href="#int_stackprotector">
313 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]314 <li><a href="#int_objectsize">
315 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]316 <li><a href="#int_expect">
317 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]318 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]319 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]320 </ol>
321 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]323
324<div class="doc_author">
325 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
326 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]329<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]330<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]331<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]332
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]333<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]334
335<p>This document is a reference manual for the LLVM assembly language. LLVM is
336 a Static Single Assignment (SSA) based representation that provides type
337 safety, low-level operations, flexibility, and the capability of representing
338 'all' high-level languages cleanly. It is the common code representation
339 used throughout all phases of the LLVM compilation strategy.</p>
340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]343<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]344<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]345<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]346
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]347<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]349<p>The LLVM code representation is designed to be used in three different forms:
350 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
351 for fast loading by a Just-In-Time compiler), and as a human readable
352 assembly language representation. This allows LLVM to provide a powerful
353 intermediate representation for efficient compiler transformations and
354 analysis, while providing a natural means to debug and visualize the
355 transformations. The three different forms of LLVM are all equivalent. This
356 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]357
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]358<p>The LLVM representation aims to be light-weight and low-level while being
359 expressive, typed, and extensible at the same time. It aims to be a
360 "universal IR" of sorts, by being at a low enough level that high-level ideas
361 may be cleanly mapped to it (similar to how microprocessors are "universal
362 IR's", allowing many source languages to be mapped to them). By providing
363 type information, LLVM can be used as the target of optimizations: for
364 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]365 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]366 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]368<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]369<h4>
370 <a name="wellformed">Well-Formedness</a>
371</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]373<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]374
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]375<p>It is important to note that this document describes 'well formed' LLVM
376 assembly language. There is a difference between what the parser accepts and
377 what is considered 'well formed'. For example, the following instruction is
378 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]379
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]380<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]381%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]382</pre>
383
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]384<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
385 LLVM infrastructure provides a verification pass that may be used to verify
386 that an LLVM module is well formed. This pass is automatically run by the
387 parser after parsing input assembly and by the optimizer before it outputs
388 bitcode. The violations pointed out by the verifier pass indicate bugs in
389 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]390
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]391</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]393</div>
394
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]395<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]396
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]397<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]398<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]399<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]401<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]402
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403<p>LLVM identifiers come in two basic types: global and local. Global
404 identifiers (functions, global variables) begin with the <tt>'@'</tt>
405 character. Local identifiers (register names, types) begin with
406 the <tt>'%'</tt> character. Additionally, there are three different formats
407 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]408
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]409<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]410 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]411 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
412 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
413 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
414 other characters in their names can be surrounded with quotes. Special
415 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
416 ASCII code for the character in hexadecimal. In this way, any character
417 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]420 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]422 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]423 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]424</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]425
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]426<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]427 don't need to worry about name clashes with reserved words, and the set of
428 reserved words may be expanded in the future without penalty. Additionally,
429 unnamed identifiers allow a compiler to quickly come up with a temporary
430 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]432<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]433 languages. There are keywords for different opcodes
434 ('<tt><a href="#i_add">add</a></tt>',
435 '<tt><a href="#i_bitcast">bitcast</a></tt>',
436 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
437 ('<tt><a href="#t_void">void</a></tt>',
438 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
439 reserved words cannot conflict with variable names, because none of them
440 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
442<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]443 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]445<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]447<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]448%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449</pre>
450
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]451<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]453<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]457<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]459<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]460%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
461%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]462%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463</pre>
464
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
466 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]468<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]470 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]471
472 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]473 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]475 <li>Unnamed temporaries are numbered sequentially</li>
476</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]477
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]478<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]479 demonstrating instructions, we will follow an instruction with a comment that
480 defines the type and name of value produced. Comments are shown in italic
481 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]482
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]483</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]484
485<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]486<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]487<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]488<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]489<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]490<h3>
491 <a name="modulestructure">Module Structure</a>
492</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]494<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]496<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
497 translation unit of the input programs. Each module consists of functions,
498 global variables, and symbol table entries. Modules may be combined together
499 with the LLVM linker, which merges function (and global variable)
500 definitions, resolves forward declarations, and merges symbol table
501 entries. Here is an example of the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]503<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]504<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]505<a href="#identifiers">@.str</a> = <a href="#linkage_private">private</a>&nbsp;<a href="#globalvars">unnamed_addr</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00"&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]506
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]507<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]508<a href="#functionstructure">declare</a> i32 @puts(i8* <a href="#nocapture">nocapture</a>) <a href="#fnattrs">nounwind</a>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]509
510<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]511define i32 @main() { <i>; i32()* </i>&nbsp;
512 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]513 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.str, i64 0, i64 0
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]514
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]515 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]516 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]517 <a href="#i_ret">ret</a> i32 0&nbsp;
518}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519
520<i>; Named metadata</i>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]521!1 = metadata !{i32 42}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]522!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]523</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]524
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]525<p>This example is made up of a <a href="#globalvars">global variable</a> named
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]526 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]527 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]528 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]529 "<tt>foo</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]530
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]531<p>In general, a module is made up of a list of global values (where both
532 functions and global variables are global values). Global values are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]533 represented by a pointer to a memory location (in this case, a pointer to an
534 array of char, and a pointer to a function), and have one of the
535 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]536
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]537</div>
538
539<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]540<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]541 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]542</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]543
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]544<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]545
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]546<p>All Global Variables and Functions have one of the following types of
547 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]548
549<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]550 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]551 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
552 by objects in the current module. In particular, linking code into a
553 module with an private global value may cause the private to be renamed as
554 necessary to avoid collisions. Because the symbol is private to the
555 module, all references can be updated. This doesn't show up in any symbol
556 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]557
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]558 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]559 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
560 assembler and evaluated by the linker. Unlike normal strong symbols, they
561 are removed by the linker from the final linked image (executable or
562 dynamic library).</dd>
563
564 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
565 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
566 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
567 linker. The symbols are removed by the linker from the final linked image
568 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]569
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
571 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
572 of the object is not taken. For instance, functions that had an inline
573 definition, but the compiler decided not to inline it. Note,
574 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
575 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
576 visibility. The symbols are removed by the linker from the final linked
577 image (executable or dynamic library).</dd>
578
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]579 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]580 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]581 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
582 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]585 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]586 into the object file corresponding to the LLVM module. They exist to
587 allow inlining and other optimizations to take place given knowledge of
588 the definition of the global, which is known to be somewhere outside the
589 module. Globals with <tt>available_externally</tt> linkage are allowed to
590 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
591 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]592
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]593 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]594 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]595 the same name when linkage occurs. This can be used to implement
596 some forms of inline functions, templates, or other code which must be
597 generated in each translation unit that uses it, but where the body may
598 be overridden with a more definitive definition later. Unreferenced
599 <tt>linkonce</tt> globals are allowed to be discarded. Note that
600 <tt>linkonce</tt> linkage does not actually allow the optimizer to
601 inline the body of this function into callers because it doesn't know if
602 this definition of the function is the definitive definition within the
603 program or whether it will be overridden by a stronger definition.
604 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
605 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]606
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]607 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]608 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
609 <tt>linkonce</tt> linkage, except that unreferenced globals with
610 <tt>weak</tt> linkage may not be discarded. This is used for globals that
611 are declared "weak" in C source code.</dd>
612
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]613 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
615 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
616 global scope.
617 Symbols with "<tt>common</tt>" linkage are merged in the same way as
618 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]619 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]620 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]621 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
622 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]623
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_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]626 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]627 pointer to array type. When two global variables with appending linkage
628 are linked together, the two global arrays are appended together. This is
629 the LLVM, typesafe, equivalent of having the system linker append together
630 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]631
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633 <dd>The semantics of this linkage follow the ELF object file model: the symbol
634 is weak until linked, if not linked, the symbol becomes null instead of
635 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]636
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
638 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 <dd>Some languages allow differing globals to be merged, such as two functions
640 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]641 that only equivalent globals are ever merged (the "one definition rule"
642 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643 and <tt>weak_odr</tt> linkage types to indicate that the global will only
644 be merged with equivalent globals. These linkage types are otherwise the
645 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]646
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]647 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]648 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]649 visible, meaning that it participates in linkage and can be used to
650 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]651</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653<p>The next two types of linkage are targeted for Microsoft Windows platform
654 only. They are designed to support importing (exporting) symbols from (to)
655 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]656
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]658 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]659 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]660 or variable via a global pointer to a pointer that is set up by the DLL
661 exporting the symbol. On Microsoft Windows targets, the pointer name is
662 formed by combining <code>__imp_</code> and the function or variable
663 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]664
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]665 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]666 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]667 pointer to a pointer in a DLL, so that it can be referenced with the
668 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
669 name is formed by combining <code>__imp_</code> and the function or
670 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]671</dl>
672
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]673<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
674 another module defined a "<tt>.LC0</tt>" variable and was linked with this
675 one, one of the two would be renamed, preventing a collision. Since
676 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
677 declarations), they are accessible outside of the current module.</p>
678
679<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]680 other than <tt>external</tt>, <tt>dllimport</tt>
681 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]682
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]683<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]684 or <tt>weak_odr</tt> linkages.</p>
685
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]686</div>
687
688<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]689<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]691</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]693<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 and <a href="#i_invoke">invokes</a> can all have an optional calling
697 convention specified for the call. The calling convention of any pair of
698 dynamic caller/callee must match, or the behavior of the program is
699 undefined. The following calling conventions are supported by LLVM, and more
700 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701
702<dl>
703 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]704 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]705 specified) matches the target C calling conventions. This calling
706 convention supports varargs function calls and tolerates some mismatch in
707 the declared prototype and implemented declaration of the function (as
708 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]709
710 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]712 (e.g. by passing things in registers). This calling convention allows the
713 target to use whatever tricks it wants to produce fast code for the
714 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]715 (Application Binary Interface).
716 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]717 when this or the GHC convention is used.</a> This calling convention
718 does not support varargs and requires the prototype of all callees to
719 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]720
721 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]722 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]723 as possible under the assumption that the call is not commonly executed.
724 As such, these calls often preserve all registers so that the call does
725 not break any live ranges in the caller side. This calling convention
726 does not support varargs and requires the prototype of all callees to
727 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]728
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]729 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
730 <dd>This calling convention has been implemented specifically for use by the
731 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
732 It passes everything in registers, going to extremes to achieve this by
733 disabling callee save registers. This calling convention should not be
734 used lightly but only for specific situations such as an alternative to
735 the <em>register pinning</em> performance technique often used when
736 implementing functional programming languages.At the moment only X86
737 supports this convention and it has the following limitations:
738 <ul>
739 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
740 floating point types are supported.</li>
741 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
742 6 floating point parameters.</li>
743 </ul>
744 This calling convention supports
745 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
746 requires both the caller and callee are using it.
747 </dd>
748
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]749 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]750 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]751 target-specific calling conventions to be used. Target specific calling
752 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]753</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]754
755<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]756 support Pascal conventions or any other well-known target-independent
757 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]758
759</div>
760
761<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]762<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]764</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]765
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]766<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]767
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]768<p>All Global Variables and Functions have one of the following visibility
769 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770
771<dl>
772 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]773 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]774 that the declaration is visible to other modules and, in shared libraries,
775 means that the declared entity may be overridden. On Darwin, default
776 visibility means that the declaration is visible to other modules. Default
777 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]778
779 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]780 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]781 object if they are in the same shared object. Usually, hidden visibility
782 indicates that the symbol will not be placed into the dynamic symbol
783 table, so no other module (executable or shared library) can reference it
784 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]785
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]786 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]787 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]788 the dynamic symbol table, but that references within the defining module
789 will bind to the local symbol. That is, the symbol cannot be overridden by
790 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]791</dl>
792
793</div>
794
795<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]796<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]797 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]798</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]800<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]801
802<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]803 it easier to read the IR and make the IR more condensed (particularly when
804 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]806<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]807%mytype = type { %mytype*, i32 }
808</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]809
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]810<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]811 "<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]812 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]813
814<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]815 and that you can therefore specify multiple names for the same type. This
816 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
817 uses structural typing, the name is not part of the type. When printing out
818 LLVM IR, the printer will pick <em>one name</em> to render all types of a
819 particular shape. This means that if you have code where two different
820 source types end up having the same LLVM type, that the dumper will sometimes
821 print the "wrong" or unexpected type. This is an important design point and
822 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]823
824</div>
825
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]826<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]827<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]828 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]829</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]830
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]831<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]832
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]833<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]834 instead of run-time. Global variables may optionally be initialized, may
835 have an explicit section to be placed in, and may have an optional explicit
836 alignment specified. A variable may be defined as "thread_local", which
837 means that it will not be shared by threads (each thread will have a
838 separated copy of the variable). A variable may be defined as a global
839 "constant," which indicates that the contents of the variable
840 will <b>never</b> be modified (enabling better optimization, allowing the
841 global data to be placed in the read-only section of an executable, etc).
842 Note that variables that need runtime initialization cannot be marked
843 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
846 constant, even if the final definition of the global is not. This capability
847 can be used to enable slightly better optimization of the program, but
848 requires the language definition to guarantee that optimizations based on the
849 'constantness' are valid for the translation units that do not include the
850 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]851
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]852<p>As SSA values, global variables define pointer values that are in scope
853 (i.e. they dominate) all basic blocks in the program. Global variables
854 always define a pointer to their "content" type because they describe a
855 region of memory, and all memory objects in LLVM are accessed through
856 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]857
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]858<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
859 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]860 like this can be merged with other constants if they have the same
861 initializer. Note that a constant with significant address <em>can</em>
862 be merged with a <tt>unnamed_addr</tt> constant, the result being a
863 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]865<p>A global variable may be declared to reside in a target-specific numbered
866 address space. For targets that support them, address spaces may affect how
867 optimizations are performed and/or what target instructions are used to
868 access the variable. The default address space is zero. The address space
869 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]870
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]871<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]872 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]873
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]874<p>An explicit alignment may be specified for a global, which must be a power
875 of 2. If not present, or if the alignment is set to zero, the alignment of
876 the global is set by the target to whatever it feels convenient. If an
877 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]878 alignment. Targets and optimizers are not allowed to over-align the global
879 if the global has an assigned section. In this case, the extra alignment
880 could be observable: for example, code could assume that the globals are
881 densely packed in their section and try to iterate over them as an array,
882 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]883
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]884<p>For example, the following defines a global in a numbered address space with
885 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]886
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]887<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]888@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]889</pre>
890
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891</div>
892
893
894<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]895<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]896 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]897</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]898
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]899<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]900
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]901<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]902 optional <a href="#linkage">linkage type</a>, an optional
903 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]904 <a href="#callingconv">calling convention</a>,
905 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]906 <a href="#paramattrs">parameter attribute</a> for the return type, a function
907 name, a (possibly empty) argument list (each with optional
908 <a href="#paramattrs">parameter attributes</a>), optional
909 <a href="#fnattrs">function attributes</a>, an optional section, an optional
910 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
911 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]912
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]913<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
914 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]915 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]916 <a href="#callingconv">calling convention</a>,
917 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]918 <a href="#paramattrs">parameter attribute</a> for the return type, a function
919 name, a possibly empty list of arguments, an optional alignment, and an
920 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]921
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]922<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]923 (Control Flow Graph) for the function. Each basic block may optionally start
924 with a label (giving the basic block a symbol table entry), contains a list
925 of instructions, and ends with a <a href="#terminators">terminator</a>
926 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]927
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]928<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]929 executed on entrance to the function, and it is not allowed to have
930 predecessor basic blocks (i.e. there can not be any branches to the entry
931 block of a function). Because the block can have no predecessors, it also
932 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]933
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]934<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]936
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]937<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]938 the alignment is set to zero, the alignment of the function is set by the
939 target to whatever it feels convenient. If an explicit alignment is
940 specified, the function is forced to have at least that much alignment. All
941 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]942
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]943<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]944 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]945
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]946<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]947<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]948define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]949 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
950 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
951 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
952 [<a href="#gc">gc</a>] { ... }
953</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]954
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]955</div>
956
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]957<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]958<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]960</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]961
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]962<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]963
964<p>Aliases act as "second name" for the aliasee value (which can be either
965 function, global variable, another alias or bitcast of global value). Aliases
966 may have an optional <a href="#linkage">linkage type</a>, and an
967 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]968
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]969<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]970<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]971@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]972</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]973
974</div>
975
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]976<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]977<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]978 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]979</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]980
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]981<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]983<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]984 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]985 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]986
987<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]988<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]989; Some unnamed metadata nodes, which are referenced by the named metadata.
990!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]991!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]992!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]993; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]994!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]995</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]996
997</div>
998
999<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1000<h3>
1001 <a name="paramattrs">Parameter Attributes</a>
1002</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1003
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1004<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005
1006<p>The return type and each parameter of a function type may have a set of
1007 <i>parameter attributes</i> associated with them. Parameter attributes are
1008 used to communicate additional information about the result or parameters of
1009 a function. Parameter attributes are considered to be part of the function,
1010 not of the function type, so functions with different parameter attributes
1011 can have the same function type.</p>
1012
1013<p>Parameter attributes are simple keywords that follow the type specified. If
1014 multiple parameter attributes are needed, they are space separated. For
1015 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1016
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1017<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1018declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1019declare i32 @atoi(i8 zeroext)
1020declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1021</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1022
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1023<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1024 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1028<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1029 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1030 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1031 should be zero-extended to the extent required by the target's ABI (which
1032 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1033 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1034
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1035 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1036 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1037 should be sign-extended to the extent required by the target's ABI (which
1038 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1039 return value).</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>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1042 <dd>This indicates that this parameter or return value should be treated in a
1043 special target-dependent fashion during while emitting code for a function
1044 call or return (usually, by putting it in a register as opposed to memory,
1045 though some targets use it to distinguish between two different kinds of
1046 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1047
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1049 <dd><p>This indicates that the pointer parameter should really be passed by
1050 value to the function. The attribute implies that a hidden copy of the
1051 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1052 is made between the caller and the callee, so the callee is unable to
1053 modify the value in the callee. This attribute is only valid on LLVM
1054 pointer arguments. It is generally used to pass structs and arrays by
1055 value, but is also valid on pointers to scalars. The copy is considered
1056 to belong to the caller not the callee (for example,
1057 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1058 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1059 values.</p>
1060
1061 <p>The byval attribute also supports specifying an alignment with
1062 the align attribute. It indicates the alignment of the stack slot to
1063 form and the known alignment of the pointer specified to the call site. If
1064 the alignment is not specified, then the code generator makes a
1065 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1067 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1068 <dd>This indicates that the pointer parameter specifies the address of a
1069 structure that is the return value of the function in the source program.
1070 This pointer must be guaranteed by the caller to be valid: loads and
1071 stores to the structure may be assumed by the callee to not to trap. This
1072 may only be applied to the first parameter. This is not a valid attribute
1073 for return values. </dd>
1074
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1075 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1076 <dd>This indicates that pointer values
1077 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1078 value do not alias pointer values which are not <i>based</i> on it,
1079 ignoring certain "irrelevant" dependencies.
1080 For a call to the parent function, dependencies between memory
1081 references from before or after the call and from those during the call
1082 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1083 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1084 The caller shares the responsibility with the callee for ensuring that
1085 these requirements are met.
1086 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1087 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1088<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1089 Note that this definition of <tt>noalias</tt> is intentionally
1090 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1091 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1092<br>
1093 For function return values, C99's <tt>restrict</tt> is not meaningful,
1094 while LLVM's <tt>noalias</tt> is.
1095 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1097 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1098 <dd>This indicates that the callee does not make any copies of the pointer
1099 that outlive the callee itself. This is not a valid attribute for return
1100 values.</dd>
1101
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1102 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1103 <dd>This indicates that the pointer parameter can be excised using the
1104 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1105 attribute for return values.</dd>
1106</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1107
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1108</div>
1109
1110<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1111<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1112 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1113</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1114
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1115<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1117<p>Each function may specify a garbage collector name, which is simply a
1118 string:</p>
1119
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1120<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1121define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1122</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1123
1124<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1125 collector which will cause the compiler to alter its output in order to
1126 support the named garbage collection algorithm.</p>
1127
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1128</div>
1129
1130<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1131<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1132 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1133</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1134
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1135<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1137<p>Function attributes are set to communicate additional information about a
1138 function. Function attributes are considered to be part of the function, not
1139 of the function type, so functions with different parameter attributes can
1140 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1141
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1142<p>Function attributes are simple keywords that follow the type specified. If
1143 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1144
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1145<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1146define void @f() noinline { ... }
1147define void @f() alwaysinline { ... }
1148define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1149define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1150</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1151
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1152<dl>
Kostya Serebryany164b86b2012-01-20 17:56:17 +0000[diff] [blame]1153 <dt><tt><b>address_safety</b></tt></dt>
1154 <dd>This attribute indicates that the address safety analysis
1155 is enabled for this function. </dd>
1156
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1157 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1158 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1159 the backend should forcibly align the stack pointer. Specify the
1160 desired alignment, which must be a power of two, in parentheses.
1161
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1162 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1163 <dd>This attribute indicates that the inliner should attempt to inline this
1164 function into callers whenever possible, ignoring any active inlining size
1165 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1166
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1167 <dt><tt><b>nonlazybind</b></tt></dt>
1168 <dd>This attribute suppresses lazy symbol binding for the function. This
1169 may make calls to the function faster, at the cost of extra program
1170 startup time if the function is not called during program startup.</dd>
1171
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1172 <dt><tt><b>inlinehint</b></tt></dt>
1173 <dd>This attribute indicates that the source code contained a hint that inlining
1174 this function is desirable (such as the "inline" keyword in C/C++). It
1175 is just a hint; it imposes no requirements on the inliner.</dd>
1176
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1177 <dt><tt><b>naked</b></tt></dt>
1178 <dd>This attribute disables prologue / epilogue emission for the function.
1179 This can have very system-specific consequences.</dd>
1180
1181 <dt><tt><b>noimplicitfloat</b></tt></dt>
1182 <dd>This attributes disables implicit floating point instructions.</dd>
1183
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1184 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1185 <dd>This attribute indicates that the inliner should never inline this
1186 function in any situation. This attribute may not be used together with
1187 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1188
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1189 <dt><tt><b>noredzone</b></tt></dt>
1190 <dd>This attribute indicates that the code generator should not use a red
1191 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1192
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1193 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1194 <dd>This function attribute indicates that the function never returns
1195 normally. This produces undefined behavior at runtime if the function
1196 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1197
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1198 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1199 <dd>This function attribute indicates that the function never returns with an
1200 unwind or exceptional control flow. If the function does unwind, its
1201 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1202
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1203 <dt><tt><b>optsize</b></tt></dt>
1204 <dd>This attribute suggests that optimization passes and code generator passes
1205 make choices that keep the code size of this function low, and otherwise
1206 do optimizations specifically to reduce code size.</dd>
1207
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute indicates that the function computes its result (or decides
1210 to unwind an exception) based strictly on its arguments, without
1211 dereferencing any pointer arguments or otherwise accessing any mutable
1212 state (e.g. memory, control registers, etc) visible to caller functions.
1213 It does not write through any pointer arguments
1214 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1215 changes any state visible to callers. This means that it cannot unwind
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1216 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1217
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1218 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1219 <dd>This attribute indicates that the function does not write through any
1220 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1221 arguments) or otherwise modify any state (e.g. memory, control registers,
1222 etc) visible to caller functions. It may dereference pointer arguments
1223 and read state that may be set in the caller. A readonly function always
1224 returns the same value (or unwinds an exception identically) when called
1225 with the same set of arguments and global state. It cannot unwind an
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1226 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1227
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1228 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1229 <dd>This attribute indicates that this function can return twice. The
1230 C <code>setjmp</code> is an example of such a function. The compiler
1231 disables some optimizations (like tail calls) in the caller of these
1232 functions.</dd>
1233
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1234 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1235 <dd>This attribute indicates that the function should emit a stack smashing
1236 protector. It is in the form of a "canary"&mdash;a random value placed on
1237 the stack before the local variables that's checked upon return from the
1238 function to see if it has been overwritten. A heuristic is used to
1239 determine if a function needs stack protectors or not.<br>
1240<br>
1241 If a function that has an <tt>ssp</tt> attribute is inlined into a
1242 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1243 function will have an <tt>ssp</tt> attribute.</dd>
1244
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1245 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1246 <dd>This attribute indicates that the function should <em>always</em> emit a
1247 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1248 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1249<br>
1250 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1251 function that doesn't have an <tt>sspreq</tt> attribute or which has
1252 an <tt>ssp</tt> attribute, then the resulting function will have
1253 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1254
1255 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1256 <dd>This attribute indicates that the ABI being targeted requires that
1257 an unwind table entry be produce for this function even if we can
1258 show that no exceptions passes by it. This is normally the case for
1259 the ELF x86-64 abi, but it can be disabled for some compilation
1260 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1261</dl>
1262
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1263</div>
1264
1265<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1266<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1267 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1268</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1269
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1270<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1271
1272<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1273 the GCC "file scope inline asm" blocks. These blocks are internally
1274 concatenated by LLVM and treated as a single unit, but may be separated in
1275 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1276
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1277<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1278module asm "inline asm code goes here"
1279module asm "more can go here"
1280</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1281
1282<p>The strings can contain any character by escaping non-printable characters.
1283 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]1284 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1285
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1286<p>The inline asm code is simply printed to the machine code .s file when
1287 assembly code is generated.</p>
1288
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1289</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1290
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1291<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1292<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1294</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1295
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1296<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1297
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1298<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1299 data is to be laid out in memory. The syntax for the data layout is
1300 simply:</p>
1301
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1302<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303target datalayout = "<i>layout specification</i>"
1304</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1305
1306<p>The <i>layout specification</i> consists of a list of specifications
1307 separated by the minus sign character ('-'). Each specification starts with
1308 a letter and may include other information after the letter to define some
1309 aspect of the data layout. The specifications accepted are as follows:</p>
1310
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1311<dl>
1312 <dt><tt>E</tt></dt>
1313 <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]1314 bits with the most significance have the lowest address location.</dd>
1315
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1316 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1317 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1318 the bits with the least significance have the lowest address
1319 location.</dd>
1320
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1321 <dt><tt>S<i>size</i></tt></dt>
1322 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1323 of stack variables is limited to the natural stack alignment to avoid
1324 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1325 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1326 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1327
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1328 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1329 <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]1330 <i>preferred</i> alignments. All sizes are in bits. Specifying
1331 the <i>pref</i> alignment is optional. If omitted, the
1332 preceding <tt>:</tt> should be omitted too.</dd>
1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1335 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1336 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1337
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1339 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1340 <i>size</i>.</dd>
1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1343 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1344 <i>size</i>. Only values of <i>size</i> that are supported by the target
1345 will work. 32 (float) and 64 (double) are supported on all targets;
1346 80 or 128 (different flavors of long double) are also supported on some
1347 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1348
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1349 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1350 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1351 <i>size</i>.</dd>
1352
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1353 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1354 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1356
1357 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1358 <dd>This specifies a set of native integer widths for the target CPU
1359 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1360 "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]1361 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1362 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1363</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1364
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1365<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1366 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1367 specifications in the <tt>datalayout</tt> keyword. The default specifications
1368 are given in this list:</p>
1369
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1370<ul>
1371 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1372 <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]1373 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1374 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1375 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1376 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1377 <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]1378 alignment of 64-bits</li>
1379 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1380 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1381 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1382 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1383 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1384 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1385</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1386
1387<p>When LLVM is determining the alignment for a given type, it uses the
1388 following rules:</p>
1389
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1390<ol>
1391 <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]1392 specification is used.</li>
1393
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1394 <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]1395 smallest integer type that is larger than the bitwidth of the sought type
1396 is used. If none of the specifications are larger than the bitwidth then
1397 the the largest integer type is used. For example, given the default
1398 specifications above, the i7 type will use the alignment of i8 (next
1399 largest) while both i65 and i256 will use the alignment of i64 (largest
1400 specified).</li>
1401
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1402 <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]1403 largest vector type that is smaller than the sought vector type will be
1404 used as a fall back. This happens because &lt;128 x double&gt; can be
1405 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1406</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1407
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1408<p>The function of the data layout string may not be what you expect. Notably,
1409 this is not a specification from the frontend of what alignment the code
1410 generator should use.</p>
1411
1412<p>Instead, if specified, the target data layout is required to match what the
1413 ultimate <em>code generator</em> expects. This string is used by the
1414 mid-level optimizers to
1415 improve code, and this only works if it matches what the ultimate code
1416 generator uses. If you would like to generate IR that does not embed this
1417 target-specific detail into the IR, then you don't have to specify the
1418 string. This will disable some optimizations that require precise layout
1419 information, but this also prevents those optimizations from introducing
1420 target specificity into the IR.</p>
1421
1422
1423
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1424</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1425
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1427<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1428 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1429</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1431<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1432
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1433<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1434with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1435is undefined. Pointer values are associated with address ranges
1436according to the following rules:</p>
1437
1438<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1439 <li>A pointer value is associated with the addresses associated with
1440 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1441 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1442 range of the variable's storage.</li>
1443 <li>The result value of an allocation instruction is associated with
1444 the address range of the allocated storage.</li>
1445 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1446 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1447 <li>An integer constant other than zero or a pointer value returned
1448 from a function not defined within LLVM may be associated with address
1449 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1450 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1451 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1452</ul>
1453
1454<p>A pointer value is <i>based</i> on another pointer value according
1455 to the following rules:</p>
1456
1457<ul>
1458 <li>A pointer value formed from a
1459 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1460 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1461 <li>The result value of a
1462 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1463 of the <tt>bitcast</tt>.</li>
1464 <li>A pointer value formed by an
1465 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1466 pointer values that contribute (directly or indirectly) to the
1467 computation of the pointer's value.</li>
1468 <li>The "<i>based</i> on" relationship is transitive.</li>
1469</ul>
1470
1471<p>Note that this definition of <i>"based"</i> is intentionally
1472 similar to the definition of <i>"based"</i> in C99, though it is
1473 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1474
1475<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1476<tt><a href="#i_load">load</a></tt> merely indicates the size and
1477alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1478interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1479<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1480and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1481
1482<p>Consequently, type-based alias analysis, aka TBAA, aka
1483<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1484LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1485additional information which specialized optimization passes may use
1486to implement type-based alias analysis.</p>
1487
1488</div>
1489
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1490<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1491<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1492 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1493</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1494
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1495<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1496
1497<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1498href="#i_store"><tt>store</tt></a>s, and <a
1499href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1500The optimizers must not change the number of volatile operations or change their
1501order of execution relative to other volatile operations. The optimizers
1502<i>may</i> change the order of volatile operations relative to non-volatile
1503operations. This is not Java's "volatile" and has no cross-thread
1504synchronization behavior.</p>
1505
1506</div>
1507
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1508<!-- ======================================================================= -->
1509<h3>
1510 <a name="memmodel">Memory Model for Concurrent Operations</a>
1511</h3>
1512
1513<div>
1514
1515<p>The LLVM IR does not define any way to start parallel threads of execution
1516or to register signal handlers. Nonetheless, there are platform-specific
1517ways to create them, and we define LLVM IR's behavior in their presence. This
1518model is inspired by the C++0x memory model.</p>
1519
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1520<p>For a more informal introduction to this model, see the
1521<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1522
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1523<p>We define a <i>happens-before</i> partial order as the least partial order
1524that</p>
1525<ul>
1526 <li>Is a superset of single-thread program order, and</li>
1527 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1528 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1529 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1530 creation, thread joining, etc., and by atomic instructions.
1531 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1532 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1533</ul>
1534
1535<p>Note that program order does not introduce <i>happens-before</i> edges
1536between a thread and signals executing inside that thread.</p>
1537
1538<p>Every (defined) read operation (load instructions, memcpy, atomic
1539loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1540(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1541stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1542initialized globals are considered to have a write of the initializer which is
1543atomic and happens before any other read or write of the memory in question.
1544For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1545any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1546
1547<ul>
1548 <li>If <var>write<sub>1</sub></var> happens before
1549 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1550 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1551 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1552 <li>If <var>R<sub>byte</sub></var> happens before
1553 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1554 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1555</ul>
1556
1557<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1558<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1559 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1560 is supposed to give guarantees which can support
1561 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1562 addresses which do not behave like normal memory. It does not generally
1563 provide cross-thread synchronization.)
1564 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1565 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1566 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1567 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1568 <var>R<sub>byte</sub></var> returns the value written by that
1569 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1570 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1571 <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]1572 values written. See the <a href="#ordering">Atomic Memory Ordering
1573 Constraints</a> section for additional constraints on how the choice
1574 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1575 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1576</ul>
1577
1578<p><var>R</var> returns the value composed of the series of bytes it read.
1579This implies that some bytes within the value may be <tt>undef</tt>
1580<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1581defines the semantics of the operation; it doesn't mean that targets will
1582emit more than one instruction to read the series of bytes.</p>
1583
1584<p>Note that in cases where none of the atomic intrinsics are used, this model
1585places only one restriction on IR transformations on top of what is required
1586for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1587otherwise be stored is not allowed in general. (Specifically, in the case
1588where another thread might write to and read from an address, introducing a
1589store can change a load that may see exactly one write into a load that may
1590see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1591
1592<!-- FIXME: This model assumes all targets where concurrency is relevant have
1593a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1594none of the backends currently in the tree fall into this category; however,
1595there might be targets which care. If there are, we want a paragraph
1596like the following:
1597
1598Targets may specify that stores narrower than a certain width are not
1599available; on such a target, for the purposes of this model, treat any
1600non-atomic write with an alignment or width less than the minimum width
1601as if it writes to the relevant surrounding bytes.
1602-->
1603
1604</div>
1605
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1606<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1607<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1608 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1609</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1610
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1611<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1612
1613<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1614<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1615<a href="#i_fence"><code>fence</code></a>,
1616<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1617<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1618that determines which other atomic instructions on the same address they
1619<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1620but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1621check those specs (see spec references in the
Nick Lewycky300a2632012-01-23 08:47:21 +0000[diff] [blame]1622<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1623<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1624treat these orderings somewhat differently since they don't take an address.
1625See that instruction's documentation for details.</p>
1626
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1627<p>For a simpler introduction to the ordering constraints, see the
1628<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1629
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1630<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1631<dt><code>unordered</code></dt>
1632<dd>The set of values that can be read is governed by the happens-before
1633partial order. A value cannot be read unless some operation wrote it.
1634This is intended to provide a guarantee strong enough to model Java's
1635non-volatile shared variables. This ordering cannot be specified for
1636read-modify-write operations; it is not strong enough to make them atomic
1637in any interesting way.</dd>
1638<dt><code>monotonic</code></dt>
1639<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1640total order for modifications by <code>monotonic</code> operations on each
1641address. All modification orders must be compatible with the happens-before
1642order. There is no guarantee that the modification orders can be combined to
1643a global total order for the whole program (and this often will not be
1644possible). The read in an atomic read-modify-write operation
1645(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1646<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1647reads the value in the modification order immediately before the value it
1648writes. If one atomic read happens before another atomic read of the same
1649address, the later read must see the same value or a later value in the
1650address's modification order. This disallows reordering of
1651<code>monotonic</code> (or stronger) operations on the same address. If an
1652address is written <code>monotonic</code>ally by one thread, and other threads
1653<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1654eventually see the write. This corresponds to the C++0x/C1x
1655<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1656<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1657<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1658a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1659operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1660<dt><code>release</code></dt>
1661<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1662writes a value which is subsequently read by an <code>acquire</code> operation,
1663it <i>synchronizes-with</i> that operation. (This isn't a complete
1664description; see the C++0x definition of a release sequence.) This corresponds
1665to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1666<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1667<code>acquire</code> and <code>release</code> operation on its address.
1668This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1669<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1670<dd>In addition to the guarantees of <code>acq_rel</code>
1671(<code>acquire</code> for an operation which only reads, <code>release</code>
1672for an operation which only writes), there is a global total order on all
1673sequentially-consistent operations on all addresses, which is consistent with
1674the <i>happens-before</i> partial order and with the modification orders of
1675all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1676preceding write to the same address in this global order. This corresponds
1677to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1678</dl>
1679
1680<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1681it only <i>synchronizes with</i> or participates in modification and seq_cst
1682total orderings with other operations running in the same thread (for example,
1683in signal handlers).</p>
1684
1685</div>
1686
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1687</div>
1688
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1689<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1690<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1691<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1692
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1693<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1694
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1695<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1696 intermediate representation. Being typed enables a number of optimizations
1697 to be performed on the intermediate representation directly, without having
1698 to do extra analyses on the side before the transformation. A strong type
1699 system makes it easier to read the generated code and enables novel analyses
1700 and transformations that are not feasible to perform on normal three address
1701 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1704<h3>
1705 <a name="t_classifications">Type Classifications</a>
1706</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1707
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1708<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1709
1710<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1711
1712<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1714 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1715 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1716 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1717 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1718 </tr>
1719 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1720 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1721 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1722 </tr>
1723 <tr>
1724 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1725 <td><a href="#t_integer">integer</a>,
1726 <a href="#t_floating">floating point</a>,
1727 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1728 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1729 <a href="#t_struct">structure</a>,
1730 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_label">label</a>,
1732 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1733 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1734 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1735 <tr>
1736 <td><a href="#t_primitive">primitive</a></td>
1737 <td><a href="#t_label">label</a>,
1738 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1739 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1740 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1741 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1742 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1743 </tr>
1744 <tr>
1745 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1746 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1747 <a href="#t_function">function</a>,
1748 <a href="#t_pointer">pointer</a>,
1749 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1750 <a href="#t_vector">vector</a>,
1751 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1752 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1753 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1754 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1756
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1757<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1758 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1759 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1762
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1763<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1764<h3>
1765 <a name="t_primitive">Primitive Types</a>
1766</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1767
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1768<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1769
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1770<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1772
1773<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1774<h4>
1775 <a name="t_integer">Integer Type</a>
1776</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1777
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1778<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1779
1780<h5>Overview:</h5>
1781<p>The integer type is a very simple type that simply specifies an arbitrary
1782 bit width for the integer type desired. Any bit width from 1 bit to
1783 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1784
1785<h5>Syntax:</h5>
1786<pre>
1787 iN
1788</pre>
1789
1790<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1791 value.</p>
1792
1793<h5>Examples:</h5>
1794<table class="layout">
1795 <tr class="layout">
1796 <td class="left"><tt>i1</tt></td>
1797 <td class="left">a single-bit integer.</td>
1798 </tr>
1799 <tr class="layout">
1800 <td class="left"><tt>i32</tt></td>
1801 <td class="left">a 32-bit integer.</td>
1802 </tr>
1803 <tr class="layout">
1804 <td class="left"><tt>i1942652</tt></td>
1805 <td class="left">a really big integer of over 1 million bits.</td>
1806 </tr>
1807</table>
1808
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1809</div>
1810
1811<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1812<h4>
1813 <a name="t_floating">Floating Point Types</a>
1814</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1815
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1816<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1817
1818<table>
1819 <tbody>
1820 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1821 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1822 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1823 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1824 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1825 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1826 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1827 </tbody>
1828</table>
1829
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1830</div>
1831
1832<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1833<h4>
1834 <a name="t_x86mmx">X86mmx Type</a>
1835</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1837<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1838
1839<h5>Overview:</h5>
1840<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>
1841
1842<h5>Syntax:</h5>
1843<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1844 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1845</pre>
1846
1847</div>
1848
1849<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1850<h4>
1851 <a name="t_void">Void Type</a>
1852</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1853
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1854<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1855
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1856<h5>Overview:</h5>
1857<p>The void type does not represent any value and has no size.</p>
1858
1859<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1860<pre>
1861 void
1862</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1863
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1864</div>
1865
1866<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1867<h4>
1868 <a name="t_label">Label Type</a>
1869</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1870
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1871<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1872
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1873<h5>Overview:</h5>
1874<p>The label type represents code labels.</p>
1875
1876<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1877<pre>
1878 label
1879</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1880
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1881</div>
1882
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1883<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1884<h4>
1885 <a name="t_metadata">Metadata Type</a>
1886</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1887
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1888<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1889
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1890<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1891<p>The metadata type represents embedded metadata. No derived types may be
1892 created from metadata except for <a href="#t_function">function</a>
1893 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1894
1895<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1896<pre>
1897 metadata
1898</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1899
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1900</div>
1901
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1902</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1903
1904<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1905<h3>
1906 <a name="t_derived">Derived Types</a>
1907</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1908
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1909<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1911<p>The real power in LLVM comes from the derived types in the system. This is
1912 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1913 useful types. Each of these types contain one or more element types which
1914 may be a primitive type, or another derived type. For example, it is
1915 possible to have a two dimensional array, using an array as the element type
1916 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1917
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1918<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1919<h4>
1920 <a name="t_aggregate">Aggregate Types</a>
1921</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1922
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1923<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1924
1925<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1926 member types. <a href="#t_array">Arrays</a> and
1927 <a href="#t_struct">structs</a> are aggregate types.
1928 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1929
1930</div>
1931
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1932<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1933<h4>
1934 <a name="t_array">Array Type</a>
1935</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1936
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1937<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1938
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1939<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1941 sequentially in memory. The array type requires a size (number of elements)
1942 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1943
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1944<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1945<pre>
1946 [&lt;# elements&gt; x &lt;elementtype&gt;]
1947</pre>
1948
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1949<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1950 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1951
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1952<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1953<table class="layout">
1954 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1955 <td class="left"><tt>[40 x i32]</tt></td>
1956 <td class="left">Array of 40 32-bit integer values.</td>
1957 </tr>
1958 <tr class="layout">
1959 <td class="left"><tt>[41 x i32]</tt></td>
1960 <td class="left">Array of 41 32-bit integer values.</td>
1961 </tr>
1962 <tr class="layout">
1963 <td class="left"><tt>[4 x i8]</tt></td>
1964 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1965 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1966</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1967<p>Here are some examples of multidimensional arrays:</p>
1968<table class="layout">
1969 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1970 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1971 <td class="left">3x4 array of 32-bit integer values.</td>
1972 </tr>
1973 <tr class="layout">
1974 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1975 <td class="left">12x10 array of single precision floating point values.</td>
1976 </tr>
1977 <tr class="layout">
1978 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1979 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1980 </tr>
1981</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1982
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1983<p>There is no restriction on indexing beyond the end of the array implied by
1984 a static type (though there are restrictions on indexing beyond the bounds
1985 of an allocated object in some cases). This means that single-dimension
1986 'variable sized array' addressing can be implemented in LLVM with a zero
1987 length array type. An implementation of 'pascal style arrays' in LLVM could
1988 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1989
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1990</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1991
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1992<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1993<h4>
1994 <a name="t_function">Function Type</a>
1995</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1997<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1998
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1999<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000<p>The function type can be thought of as a function signature. It consists of
2001 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]2002 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]2003
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2004<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2005<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2006 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2007</pre>
2008
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2009<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]2010 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2011 which indicates that the function takes a variable number of arguments.
2012 Variable argument functions can access their arguments with
2013 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2014 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2015 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2017<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2018<table class="layout">
2019 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2020 <td class="left"><tt>i32 (i32)</tt></td>
2021 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2022 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2023 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2024 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2025 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2026 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2027 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2028 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2029 </td>
2030 </tr><tr class="layout">
2031 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2032 <td class="left">A vararg function that takes at least one
2033 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2034 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2035 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2036 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2037 </tr><tr class="layout">
2038 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2039 <td class="left">A function taking an <tt>i32</tt>, returning a
2040 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2041 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2042 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2044
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2045</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2046
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2047<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2048<h4>
2049 <a name="t_struct">Structure Type</a>
2050</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2051
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2052<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2053
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2055<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2056 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]2057
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2058<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2059 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2060 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2061 Structures in registers are accessed using the
2062 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2063 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2064
2065<p>Structures may optionally be "packed" structures, which indicate that the
2066 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2067 the elements. In non-packed structs, padding between field types is inserted
2068 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2069 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2070
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2071<p>Structures can either be "literal" or "identified". A literal structure is
2072 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2073 types are always defined at the top level with a name. Literal types are
2074 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2075 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]2076 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2077</p>
2078
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2079<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2080<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2081 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2082 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2083</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2084
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2085<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2086<table class="layout">
2087 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2088 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2089 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2090 </tr>
2091 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2092 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2093 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2094 second element is a <a href="#t_pointer">pointer</a> to a
2095 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2096 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2097 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2098 <tr class="layout">
2099 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2100 <td class="left">A packed struct known to be 5 bytes in size.</td>
2101 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2102</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2103
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2104</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2105
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2106<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2107<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2108 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2109</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2110
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2111<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2112
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2113<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2114<p>Opaque structure types are used to represent named structure types that do
2115 not have a body specified. This corresponds (for example) to the C notion of
2116 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2117
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2118<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2119<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2120 %X = type opaque
2121 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2122</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2123
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2124<h5>Examples:</h5>
2125<table class="layout">
2126 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2127 <td class="left"><tt>opaque</tt></td>
2128 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2129 </tr>
2130</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2131
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2132</div>
2133
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2134
2135
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2136<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2137<h4>
2138 <a name="t_pointer">Pointer Type</a>
2139</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2140
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2141<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142
2143<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2144<p>The pointer type is used to specify memory locations.
2145 Pointers are commonly used to reference objects in memory.</p>
2146
2147<p>Pointer types may have an optional address space attribute defining the
2148 numbered address space where the pointed-to object resides. The default
2149 address space is number zero. The semantics of non-zero address
2150 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2151
2152<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2153 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2154
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2155<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2156<pre>
2157 &lt;type&gt; *
2158</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2159
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2160<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2161<table class="layout">
2162 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2163 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2164 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2165 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2166 </tr>
2167 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2168 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2169 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2170 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2171 <tt>i32</tt>.</td>
2172 </tr>
2173 <tr class="layout">
2174 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2175 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2176 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2177 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2178</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2179
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2180</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2181
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2182<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2183<h4>
2184 <a name="t_vector">Vector Type</a>
2185</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2186
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2187<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2188
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2189<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2190<p>A vector type is a simple derived type that represents a vector of elements.
2191 Vector types are used when multiple primitive data are operated in parallel
2192 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2193 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2194 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2195
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2196<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2197<pre>
2198 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2199</pre>
2200
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2201<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2202 may be any integer or floating point type, or a pointer to these types.
2203 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2204
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2205<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2206<table class="layout">
2207 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2208 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2209 <td class="left">Vector of 4 32-bit integer values.</td>
2210 </tr>
2211 <tr class="layout">
2212 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2213 <td class="left">Vector of 8 32-bit floating-point values.</td>
2214 </tr>
2215 <tr class="layout">
2216 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2217 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2218 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2219 <tr class="layout">
2220 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2221 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2222 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2223</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2225</div>
2226
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2227</div>
2228
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2229</div>
2230
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2231<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2232<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2233<!-- *********************************************************************** -->
2234
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2235<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2236
2237<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2238 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2239
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2240<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2241<h3>
2242 <a name="simpleconstants">Simple Constants</a>
2243</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2244
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2245<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2246
2247<dl>
2248 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2249 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2250 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2251
2252 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2253 <dd>Standard integers (such as '4') are constants of
2254 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2255 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2256
2257 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2258 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2259 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2260 notation (see below). The assembler requires the exact decimal value of a
2261 floating-point constant. For example, the assembler accepts 1.25 but
2262 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2263 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2264
2265 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2266 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2267 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2268</dl>
2269
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2270<p>The one non-intuitive notation for constants is the hexadecimal form of
2271 floating point constants. For example, the form '<tt>double
2272 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2273 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2274 constants are required (and the only time that they are generated by the
2275 disassembler) is when a floating point constant must be emitted but it cannot
2276 be represented as a decimal floating point number in a reasonable number of
2277 digits. For example, NaN's, infinities, and other special values are
2278 represented in their IEEE hexadecimal format so that assembly and disassembly
2279 do not cause any bits to change in the constants.</p>
2280
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2281<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2282 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2283 representation for double); half and float values must, however, be exactly
2284 representable as IEE754 half and single precision, respectively.
2285 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2286 for long double, and there are three forms of long double. The 80-bit format
2287 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2288 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2289 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2290 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2291 currently supported target uses this format. Long doubles will only work if
2292 they match the long double format on your target. All hexadecimal formats
2293 are big-endian (sign bit at the left).</p>
2294
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2295<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2296</div>
2297
2298<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2299<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2300<a name="aggregateconstants"></a> <!-- old anchor -->
2301<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2302</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2303
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2304<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2306<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2307 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2308
2309<dl>
2310 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2311 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312 type definitions (a comma separated list of elements, surrounded by braces
2313 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2314 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2315 Structure constants must have <a href="#t_struct">structure type</a>, and
2316 the number and types of elements must match those specified by the
2317 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2318
2319 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2320 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2321 definitions (a comma separated list of elements, surrounded by square
2322 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2323 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2324 the number and types of elements must match those specified by the
2325 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2326
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2327 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2328 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2329 definitions (a comma separated list of elements, surrounded by
2330 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2331 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2332 have <a href="#t_vector">vector type</a>, and the number and types of
2333 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2334
2335 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2336 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2337 value to zero of <em>any</em> type, including scalar and
2338 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2339 This is often used to avoid having to print large zero initializers
2340 (e.g. for large arrays) and is always exactly equivalent to using explicit
2341 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2342
2343 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2344 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2345 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2346 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2347 be interpreted as part of the instruction stream, metadata is a place to
2348 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2349</dl>
2350
2351</div>
2352
2353<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2354<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2355 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2356</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2357
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2358<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2359
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2360<p>The addresses of <a href="#globalvars">global variables</a>
2361 and <a href="#functionstructure">functions</a> are always implicitly valid
2362 (link-time) constants. These constants are explicitly referenced when
2363 the <a href="#identifiers">identifier for the global</a> is used and always
2364 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2365 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2366
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2367<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2368@X = global i32 17
2369@Y = global i32 42
2370@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2371</pre>
2372
2373</div>
2374
2375<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2376<h3>
2377 <a name="undefvalues">Undefined Values</a>
2378</h3>
2379
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2380<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2381
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2382<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]2383 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2384 Undefined values may be of any type (other than '<tt>label</tt>'
2385 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2386
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2387<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2388 program is well defined no matter what value is used. This gives the
2389 compiler more freedom to optimize. Here are some examples of (potentially
2390 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2391
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2392
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2393<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2394 %A = add %X, undef
2395 %B = sub %X, undef
2396 %C = xor %X, undef
2397Safe:
2398 %A = undef
2399 %B = undef
2400 %C = undef
2401</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2402
2403<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]2404 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]2405
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2406<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2407 %A = or %X, undef
2408 %B = and %X, undef
2409Safe:
2410 %A = -1
2411 %B = 0
2412Unsafe:
2413 %A = undef
2414 %B = undef
2415</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2416
2417<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2418 For example, if <tt>%X</tt> has a zero bit, then the output of the
2419 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2420 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2421 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2422 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2423 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2424 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2425 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2426
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2427<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2428 %A = select undef, %X, %Y
2429 %B = select undef, 42, %Y
2430 %C = select %X, %Y, undef
2431Safe:
2432 %A = %X (or %Y)
2433 %B = 42 (or %Y)
2434 %C = %Y
2435Unsafe:
2436 %A = undef
2437 %B = undef
2438 %C = undef
2439</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2440
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2441<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2442 branch) conditions can go <em>either way</em>, but they have to come from one
2443 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2444 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2445 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2446 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2447 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2448 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2449
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2450<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2451 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2452
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2453 %B = undef
2454 %C = xor %B, %B
2455
2456 %D = undef
2457 %E = icmp lt %D, 4
2458 %F = icmp gte %D, 4
2459
2460Safe:
2461 %A = undef
2462 %B = undef
2463 %C = undef
2464 %D = undef
2465 %E = undef
2466 %F = undef
2467</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2468
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2469<p>This example points out that two '<tt>undef</tt>' operands are not
2470 necessarily the same. This can be surprising to people (and also matches C
2471 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2472 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2473 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2474 its value over its "live range". This is true because the variable doesn't
2475 actually <em>have a live range</em>. Instead, the value is logically read
2476 from arbitrary registers that happen to be around when needed, so the value
2477 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2478 need to have the same semantics or the core LLVM "replace all uses with"
2479 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2480
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2481<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2482 %A = fdiv undef, %X
2483 %B = fdiv %X, undef
2484Safe:
2485 %A = undef
2486b: unreachable
2487</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2488
2489<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2490 value</em> and <em>undefined behavior</em>. An undefined value (like
2491 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2492 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2493 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2494 defined on SNaN's. However, in the second example, we can make a more
2495 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2496 arbitrary value, we are allowed to assume that it could be zero. Since a
2497 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2498 the operation does not execute at all. This allows us to delete the divide and
2499 all code after it. Because the undefined operation "can't happen", the
2500 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2501
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2502<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2503a: store undef -> %X
2504b: store %X -> undef
2505Safe:
2506a: &lt;deleted&gt;
2507b: unreachable
2508</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2509
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2510<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2511 undefined value can be assumed to not have any effect; we can assume that the
2512 value is overwritten with bits that happen to match what was already there.
2513 However, a store <em>to</em> an undefined location could clobber arbitrary
2514 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2515
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2516</div>
2517
2518<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2519<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2520 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2521</h3>
2522
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2523<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2524
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2525<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2526 they also represent the fact that an instruction or constant expression which
2527 cannot evoke side effects has nevertheless detected a condition which results
2528 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2529
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2530<p>There is currently no way of representing a poison value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2531 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2532 <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]2533
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2534<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2535
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2536<ul>
2537<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2538 their operands.</li>
2539
2540<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2541 to their dynamic predecessor basic block.</li>
2542
2543<li>Function arguments depend on the corresponding actual argument values in
2544 the dynamic callers of their functions.</li>
2545
2546<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2547 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2548 control back to them.</li>
2549
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2550<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]2551 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_resume"><tt>resume</tt></a>,
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2552 or exception-throwing call instructions that dynamically transfer control
2553 back to them.</li>
2554
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2555<li>Non-volatile loads and stores depend on the most recent stores to all of the
2556 referenced memory addresses, following the order in the IR
2557 (including loads and stores implied by intrinsics such as
2558 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2559
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2560<!-- TODO: In the case of multiple threads, this only applies if the store
2561 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2562
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2563<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2564
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2565<li>An instruction with externally visible side effects depends on the most
2566 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2567 the order in the IR. (This includes
2568 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2569
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2570<li>An instruction <i>control-depends</i> on a
2571 <a href="#terminators">terminator instruction</a>
2572 if the terminator instruction has multiple successors and the instruction
2573 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2574 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2575
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2576<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2577 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2578 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2579 successor.</li>
2580
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2581<li>Dependence is transitive.</li>
2582
2583</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2584
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2585<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2586 with the additional affect that any instruction which has a <i>dependence</i>
2587 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2588
2589<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2590
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2591<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2592entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2593 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2594 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2595 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2596 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2597
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2598 store i32 %poison, i32* @g ; Poison value stored to memory.
2599 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2600
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2601 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2602
2603 %narrowaddr = bitcast i32* @g to i16*
2604 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2605 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2606 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2607
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2608 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2609 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2610
2611true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2612 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2613 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2614 br label %end
2615
2616end:
2617 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2618 ; Both edges into this PHI are
2619 ; control-dependent on %cmp, so this
2620 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2621
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2622 store volatile i32 0, i32* @g ; This would depend on the store in %true
2623 ; if %cmp is true, or the store in %entry
2624 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2625
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2626 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2627 ; The same branch again, but this time the
2628 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2629
2630second_true:
2631 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2632 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2633
2634second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2635 store volatile i32 0, i32* @g ; This time, the instruction always depends
2636 ; on the store in %end. Also, it is
2637 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2638 ; well-defined (ignoring earlier undefined
2639 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2640</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2641
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2642</div>
2643
2644<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2645<h3>
2646 <a name="blockaddress">Addresses of Basic Blocks</a>
2647</h3>
2648
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2649<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2650
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2651<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2652
2653<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2654 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2655 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2656
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2657<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2658 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2659 comparisons against null. Pointer equality tests between labels addresses
2660 results in undefined behavior &mdash; though, again, comparison against null
2661 is ok, and no label is equal to the null pointer. This may be passed around
2662 as an opaque pointer sized value as long as the bits are not inspected. This
2663 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2664 long as the original value is reconstituted before the <tt>indirectbr</tt>
2665 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2666
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2667<p>Finally, some targets may provide defined semantics when using the value as
2668 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2669
2670</div>
2671
2672
2673<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2674<h3>
2675 <a name="constantexprs">Constant Expressions</a>
2676</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2678<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2679
2680<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2681 to be used as constants. Constant expressions may be of
2682 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2683 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2684 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2685
2686<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2687 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2688 <dd>Truncate a constant to another type. The bit size of CST must be larger
2689 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2690
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2691 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2692 <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]2693 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2694
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2695 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2696 <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]2697 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2698
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2699 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2700 <dd>Truncate a floating point constant to another floating point type. The
2701 size of CST must be larger than the size of TYPE. Both types must be
2702 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2703
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2704 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2705 <dd>Floating point extend a constant to another type. The size of CST must be
2706 smaller or equal to the size of TYPE. Both types must be floating
2707 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2708
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2709 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2710 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2711 constant. TYPE must be a scalar or vector integer type. CST must be of
2712 scalar or vector floating point type. Both CST and TYPE must be scalars,
2713 or vectors of the same number of elements. If the value won't fit in the
2714 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2715
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2716 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2717 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2718 constant. TYPE must be a scalar or vector integer type. CST must be of
2719 scalar or vector floating point type. Both CST and TYPE must be scalars,
2720 or vectors of the same number of elements. If the value won't fit in the
2721 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2722
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2723 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2724 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2725 constant. TYPE must be a scalar or vector floating point type. CST must be
2726 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2727 vectors of the same number of elements. If the value won't fit in the
2728 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2729
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2730 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2731 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2732 constant. TYPE must be a scalar or vector floating point type. CST must be
2733 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2734 vectors of the same number of elements. If the value won't fit in the
2735 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2736
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2737 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2738 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2739 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2740 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2741 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2742
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2743 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2744 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2745 type. CST must be of integer type. The CST value is zero extended,
2746 truncated, or unchanged to make it fit in a pointer size. This one is
2747 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2748
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2750 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2751 are the same as those for the <a href="#i_bitcast">bitcast
2752 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2753
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2754 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2755 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2756 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2757 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2758 instruction, the index list may have zero or more indexes, which are
2759 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2760
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2761 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2762 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2763
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2764 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2765 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2766
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2767 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2768 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2769
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2770 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2771 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2772 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2773
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2774 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2775 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2776 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2777
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2778 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2779 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2780 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2781
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2782 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2783 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2784 constants. The index list is interpreted in a similar manner as indices in
2785 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2786 index value must be specified.</dd>
2787
2788 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2789 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2790 constants. The index list is interpreted in a similar manner as indices in
2791 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2792 index value must be specified.</dd>
2793
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2794 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2795 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2796 be any of the <a href="#binaryops">binary</a>
2797 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2798 on operands are the same as those for the corresponding instruction
2799 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2801
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2802</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2803
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2804</div>
2805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2806<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2807<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2808<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2809<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2810<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2811<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2812<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2813</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2814
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2815<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2816
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2817<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2818 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2819 a special value. This value represents the inline assembler as a string
2820 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2821 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2822 expression has side effects, and a flag indicating whether the function
2823 containing the asm needs to align its stack conservatively. An example
2824 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2825
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2826<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2827i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2828</pre>
2829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2830<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2831 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2832 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2833
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2834<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2835%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]2836</pre>
2837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2838<p>Inline asms with side effects not visible in the constraint list must be
2839 marked as having side effects. This is done through the use of the
2840 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2841
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2842<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2843call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2844</pre>
2845
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2846<p>In some cases inline asms will contain code that will not work unless the
2847 stack is aligned in some way, such as calls or SSE instructions on x86,
2848 yet will not contain code that does that alignment within the asm.
2849 The compiler should make conservative assumptions about what the asm might
2850 contain and should generate its usual stack alignment code in the prologue
2851 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2852
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2853<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2854call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2855</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2856
2857<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2858 first.</p>
2859
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2860<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2861<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2862 documented here. Constraints on what can be done (e.g. duplication, moving,
2863 etc need to be documented). This is probably best done by reference to
2864 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2865 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2866
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2867<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2868<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2869 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2870</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2871
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2872<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2873
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2874<p>The call instructions that wrap inline asm nodes may have a
2875 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2876 integers. If present, the code generator will use the integer as the
2877 location cookie value when report errors through the <tt>LLVMContext</tt>
2878 error reporting mechanisms. This allows a front-end to correlate backend
2879 errors that occur with inline asm back to the source code that produced it.
2880 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2881
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2882<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2883call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2884...
2885!42 = !{ i32 1234567 }
2886</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2887
2888<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]2889 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2890 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]2891
2892</div>
2893
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2894</div>
2895
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2896<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2897<h3>
2898 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2899</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2900
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2901<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2902
2903<p>LLVM IR allows metadata to be attached to instructions in the program that
2904 can convey extra information about the code to the optimizers and code
2905 generator. One example application of metadata is source-level debug
2906 information. There are two metadata primitives: strings and nodes. All
2907 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2908 preceding exclamation point ('<tt>!</tt>').</p>
2909
2910<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2911 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2912 "<tt>xx</tt>" is the two digit hex code. For example:
2913 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2914
2915<p>Metadata nodes are represented with notation similar to structure constants
2916 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2917 exclamation point). Metadata nodes can have any values as their operand. For
2918 example:</p>
2919
2920<div class="doc_code">
2921<pre>
2922!{ metadata !"test\00", i32 10}
2923</pre>
2924</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2925
2926<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2927 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2928 example:</p>
2929
2930<div class="doc_code">
2931<pre>
2932!foo = metadata !{!4, !3}
2933</pre>
2934</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2935
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2936<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2937 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2938
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2939<div class="doc_code">
2940<pre>
2941call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2942</pre>
2943</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2944
2945<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2946 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2947 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2948
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2949<div class="doc_code">
2950<pre>
2951%indvar.next = add i64 %indvar, 1, !dbg !21
2952</pre>
2953</div>
2954
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2955<p>More information about specific metadata nodes recognized by the optimizers
2956 and code generator is found below.</p>
2957
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2958<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2959<h4>
2960 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2961</h4>
2962
2963<div>
2964
2965<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2966 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2967 a type system of a higher level language. This can be used to implement
2968 typical C/C++ TBAA, but it can also be used to implement custom alias
2969 analysis behavior for other languages.</p>
2970
2971<p>The current metadata format is very simple. TBAA metadata nodes have up to
2972 three fields, e.g.:</p>
2973
2974<div class="doc_code">
2975<pre>
2976!0 = metadata !{ metadata !"an example type tree" }
2977!1 = metadata !{ metadata !"int", metadata !0 }
2978!2 = metadata !{ metadata !"float", metadata !0 }
2979!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2980</pre>
2981</div>
2982
2983<p>The first field is an identity field. It can be any value, usually
2984 a metadata string, which uniquely identifies the type. The most important
2985 name in the tree is the name of the root node. Two trees with
2986 different root node names are entirely disjoint, even if they
2987 have leaves with common names.</p>
2988
2989<p>The second field identifies the type's parent node in the tree, or
2990 is null or omitted for a root node. A type is considered to alias
2991 all of its descendants and all of its ancestors in the tree. Also,
2992 a type is considered to alias all types in other trees, so that
2993 bitcode produced from multiple front-ends is handled conservatively.</p>
2994
2995<p>If the third field is present, it's an integer which if equal to 1
2996 indicates that the type is "constant" (meaning
2997 <tt>pointsToConstantMemory</tt> should return true; see
2998 <a href="AliasAnalysis.html#OtherItfs">other useful
2999 <tt>AliasAnalysis</tt> methods</a>).</p>
3000
3001</div>
3002
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]3003<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3004<h4>
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3005 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3006</h4>
3007
3008<div>
3009
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3010<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3011 type. It can be used to express the maximum acceptable error in the result of
3012 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3013 more efficient but less accurate method of computing it. ULP is defined as
3014 follows:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3015
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3016<blockquote>
3017
3018<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3019 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3020 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3021 distance between the two non-equal finite floating-point numbers nearest
3022 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3023
3024</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3025
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3026<p>The metadata node shall consist of a single positive floating point number
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3027 representing the maximum relative error, for example:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3028
3029<div class="doc_code">
3030<pre>
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3031!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3032</pre>
3033</div>
3034
NAKAMURA Takumi9c55f592012-03-27 11:25:16 +0000[diff] [blame]3035</div>
3036
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3037<!-- _______________________________________________________________________ -->
3038<h4>
3039 <a name="range">'<tt>range</tt>' Metadata</a>
3040</h4>
3041
3042<div>
3043<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3044 expresses the possible ranges the loaded value is in. The ranges are
3045 represented with a flattened list of integers. The loaded value is known to
3046 be in the union of the ranges defined by each consecutive pair. Each pair
3047 has the following properties:</p>
3048<ul>
3049 <li>The type must match the type loaded by the instruction.</li>
3050 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3051 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3052 <li>The range is allowed to wrap.</li>
3053 <li>The range should not represent the full or empty set. That is,
3054 <tt>a!=b</tt>. </li>
3055</ul>
3056
3057<p>Examples:</p>
3058<div class="doc_code">
3059<pre>
3060 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3061 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3062 %c = load i8* %z, align 1, !range !2 ; Can only be 0, 1, 3, 4 or 5
3063...
3064!0 = metadata !{ i8 0, i8 2 }
3065!1 = metadata !{ i8 255, i8 2 }
3066!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
3067</pre>
3068</div>
3069</div>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3070</div>
3071
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3072</div>
3073
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3074<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3075<h2>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3076 <a name="module_flags">Module Flags Metadata</a>
3077</h2>
3078<!-- *********************************************************************** -->
3079
3080<div>
3081
3082<p>Information about the module as a whole is difficult to convey to LLVM's
3083 subsystems. The LLVM IR isn't sufficient to transmit this
3084 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3085 facilitate this. These flags are in the form of key / value pairs &mdash;
3086 much like a dictionary &mdash; making it easy for any subsystem who cares
3087 about a flag to look it up.</p>
3088
3089<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3090 triplets. Each triplet has the following form:</p>
3091
3092<ul>
3093 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3094 when two (or more) modules are merged together, and it encounters two (or
3095 more) metadata with the same ID. The supported behaviors are described
3096 below.</li>
3097
3098 <li>The second element is a metadata string that is a unique ID for the
3099 metadata. How each ID is interpreted is documented below.</li>
3100
3101 <li>The third element is the value of the flag.</li>
3102</ul>
3103
3104<p>When two (or more) modules are merged together, the resulting
3105 <tt>llvm.module.flags</tt> metadata is the union of the
3106 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3107 with the <i>Override</i> behavior, which may override another flag's value
3108 (see below).</p>
3109
3110<p>The following behaviors are supported:</p>
3111
3112<table border="1" cellspacing="0" cellpadding="4">
3113 <tbody>
3114 <tr>
3115 <th>Value</th>
3116 <th>Behavior</th>
3117 </tr>
3118 <tr>
3119 <td>1</td>
3120 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3121 <dl>
3122 <dt><b>Error</b></dt>
3123 <dd>Emits an error if two values disagree. It is an error to have an ID
3124 with both an Error and a Warning behavior.</dd>
3125 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3126 </td>
3127 </tr>
3128 <tr>
3129 <td>2</td>
3130 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3131 <dl>
3132 <dt><b>Warning</b></dt>
3133 <dd>Emits a warning if two values disagree.</dd>
3134 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3135 </td>
3136 </tr>
3137 <tr>
3138 <td>3</td>
3139 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3140 <dl>
3141 <dt><b>Require</b></dt>
3142 <dd>Emits an error when the specified value is not present or doesn't
3143 have the specified value. It is an error for two (or more)
3144 <tt>llvm.module.flags</tt> with the same ID to have the Require
3145 behavior but different values. There may be multiple Require flags
3146 per ID.</dd>
3147 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3148 </td>
3149 </tr>
3150 <tr>
3151 <td>4</td>
3152 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3153 <dl>
3154 <dt><b>Override</b></dt>
3155 <dd>Uses the specified value if the two values disagree. It is an
3156 error for two (or more) <tt>llvm.module.flags</tt> with the same
3157 ID to have the Override behavior but different values.</dd>
3158 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3159 </td>
3160 </tr>
3161 </tbody>
3162</table>
3163
3164<p>An example of module flags:</p>
3165
3166<pre class="doc_code">
3167!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3168!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3169!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3170!3 = metadata !{ i32 3, metadata !"qux",
3171 metadata !{
3172 metadata !"foo", i32 1
3173 }
3174}
3175!llvm.module.flags = !{ !0, !1, !2, !3 }
3176</pre>
3177
3178<ul>
3179 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3180 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3181 error if their values are not equal.</p></li>
3182
3183 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3184 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3185 value '37' if their values are not equal.</p></li>
3186
3187 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3188 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3189 warning if their values are not equal.</p></li>
3190
3191 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3192
3193<pre class="doc_code">
3194metadata !{ metadata !"foo", i32 1 }
3195</pre>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3196
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3197 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3198 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3199 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3200 the same value or an error will be issued.</p></li>
3201</ul>
3202
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3203
3204<!-- ======================================================================= -->
3205<h3>
3206<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3207</h3>
3208
3209<div>
3210
3211<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3212 in a special section called "image info". The metadata consists of a version
3213 number and a bitmask specifying what types of garbage collection are
3214 supported (if any) by the file. If two or more modules are linked together
3215 their garbage collection metadata needs to be merged rather than appended
3216 together.</p>
3217
3218<p>The Objective-C garbage collection module flags metadata consists of the
3219 following key-value pairs:</p>
3220
3221<table border="1" cellspacing="0" cellpadding="4">
Bill Wendlingb3ef2232012-03-06 09:23:25 +0000[diff] [blame]3222 <col width="30%">
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3223 <tbody>
3224 <tr>
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3225 <th>Key</th>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3226 <th>Value</th>
3227 </tr>
3228 <tr>
3229 <td><tt>Objective-C&nbsp;Version</tt></td>
3230 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3231 version. Valid values are 1 and 2.</td>
3232 </tr>
3233 <tr>
3234 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3235 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3236 section. Currently always 0.</td>
3237 </tr>
3238 <tr>
3239 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3240 <td align="left"><b>[Required]</b> &mdash; The section to place the
3241 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3242 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3243 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3244 </tr>
3245 <tr>
3246 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3247 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3248 collection is supported or not. Valid values are 0, for no garbage
3249 collection, and 2, for garbage collection supported.</td>
3250 </tr>
3251 <tr>
3252 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3253 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3254 collection is supported. If present, its value must be 6. This flag
3255 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3256 value 2.</td>
3257 </tr>
3258 </tbody>
3259</table>
3260
3261<p>Some important flag interactions:</p>
3262
3263<ul>
3264 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3265 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3266 2, then the resulting module has the <tt>Objective-C Garbage
3267 Collection</tt> flag set to 0.</li>
3268
3269 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3270 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3271</ul>
3272
3273</div>
3274
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3275</div>
3276
3277<!-- *********************************************************************** -->
3278<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3279 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3280</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3281<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3282<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3283<p>LLVM has a number of "magic" global variables that contain data that affect
3284code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3285of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3286section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3287by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3288
3289<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3290<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3291<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3292</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3293
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3294<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3295
3296<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3297href="#linkage_appending">appending linkage</a>. This array contains a list of
3298pointers to global variables and functions which may optionally have a pointer
3299cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3300
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3301<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3302<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3303@X = global i8 4
3304@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3305
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3306@llvm.used = appending global [2 x i8*] [
3307 i8* @X,
3308 i8* bitcast (i32* @Y to i8*)
3309], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3310</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3311</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3312
3313<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]3314 compiler, assembler, and linker are required to treat the symbol as if there
3315 is a reference to the global that it cannot see. For example, if a variable
3316 has internal linkage and no references other than that from
3317 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3318 represent references from inline asms and other things the compiler cannot
3319 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3320
3321<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]3322 object file to prevent the assembler and linker from molesting the
3323 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3324
3325</div>
3326
3327<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3328<h3>
3329 <a name="intg_compiler_used">
3330 The '<tt>llvm.compiler.used</tt>' Global Variable
3331 </a>
3332</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3333
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3334<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3335
3336<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3337 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3338 touching the symbol. On targets that support it, this allows an intelligent
3339 linker to optimize references to the symbol without being impeded as it would
3340 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3341
3342<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]3343 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3344
3345</div>
3346
3347<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3348<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3349<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3350</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3351
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3352<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3353
3354<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3355<pre>
3356%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3357@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3358</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3359</div>
3360
3361<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3362 functions and associated priorities. The functions referenced by this array
3363 will be called in ascending order of priority (i.e. lowest first) when the
3364 module is loaded. The order of functions with the same priority is not
3365 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3366
3367</div>
3368
3369<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3370<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3371<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3372</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3373
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3374<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3375
3376<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3377<pre>
3378%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3379@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3380</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3381</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3382
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3383<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3384 and associated priorities. The functions referenced by this array will be
3385 called in descending order of priority (i.e. highest first) when the module
3386 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3387
3388</div>
3389
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3390</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3391
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3392<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3393<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3394<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3395
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3396<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3397
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398<p>The LLVM instruction set consists of several different classifications of
3399 instructions: <a href="#terminators">terminator
3400 instructions</a>, <a href="#binaryops">binary instructions</a>,
3401 <a href="#bitwiseops">bitwise binary instructions</a>,
3402 <a href="#memoryops">memory instructions</a>, and
3403 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3404
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3405<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3406<h3>
3407 <a name="terminators">Terminator Instructions</a>
3408</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3409
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3410<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3411
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3412<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3413 in a program ends with a "Terminator" instruction, which indicates which
3414 block should be executed after the current block is finished. These
3415 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3416 control flow, not values (the one exception being the
3417 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3418
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3419<p>The terminator instructions are:
3420 '<a href="#i_ret"><tt>ret</tt></a>',
3421 '<a href="#i_br"><tt>br</tt></a>',
3422 '<a href="#i_switch"><tt>switch</tt></a>',
3423 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3424 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3425 '<a href="#i_resume"><tt>resume</tt></a>', and
3426 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3427
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3428<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3429<h4>
3430 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3431</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3433<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3435<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3436<pre>
3437 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]3438 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3439</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3440
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3441<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3442<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3443 a value) from a function back to the caller.</p>
3444
3445<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3446 value and then causes control flow, and one that just causes control flow to
3447 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3448
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3449<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3450<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3451 return value. The type of the return value must be a
3452 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3453
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3455 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3456 value or a return value with a type that does not match its type, or if it
3457 has a void return type and contains a '<tt>ret</tt>' instruction with a
3458 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3460<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3461<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3462 the calling function's context. If the caller is a
3463 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3464 instruction after the call. If the caller was an
3465 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3466 the beginning of the "normal" destination block. If the instruction returns
3467 a value, that value shall set the call or invoke instruction's return
3468 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3471<pre>
3472 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3473 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3474 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]3475</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3476
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3477</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3478<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3479<h4>
3480 <a name="i_br">'<tt>br</tt>' Instruction</a>
3481</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3483<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3485<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3487 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3488 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3489</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3490
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3491<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3492<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3493 different basic block in the current function. There are two forms of this
3494 instruction, corresponding to a conditional branch and an unconditional
3495 branch.</p>
3496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3497<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3499 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3500 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3501 target.</p>
3502
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3503<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3504<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3506 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3507 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3508
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3509<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3510<pre>
3511Test:
3512 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3513 br i1 %cond, label %IfEqual, label %IfUnequal
3514IfEqual:
3515 <a href="#i_ret">ret</a> i32 1
3516IfUnequal:
3517 <a href="#i_ret">ret</a> i32 0
3518</pre>
3519
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3520</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3522<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3523<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3524 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3525</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3526
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3527<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3528
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3529<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3530<pre>
3531 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3532</pre>
3533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3534<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3535<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]3536 several different places. It is a generalization of the '<tt>br</tt>'
3537 instruction, allowing a branch to occur to one of many possible
3538 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3539
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3540<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3541<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3542 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3543 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3544 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3545
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3546<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3549 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3550 transferred to the corresponding destination; otherwise, control flow is
3551 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3552
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3553<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3554<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555 <tt>switch</tt> instruction, this instruction may be code generated in
3556 different ways. For example, it could be generated as a series of chained
3557 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3558
3559<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3560<pre>
3561 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3562 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3563 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3564
3565 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3566 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3567
3568 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3569 switch i32 %val, label %otherwise [ i32 0, label %onzero
3570 i32 1, label %onone
3571 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3572</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3574</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3575
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3576
3577<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3578<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3579 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3580</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3581
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3582<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3583
3584<h5>Syntax:</h5>
3585<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3586 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]3587</pre>
3588
3589<h5>Overview:</h5>
3590
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3591<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3592 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3593 "<tt>address</tt>". Address must be derived from a <a
3594 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3595
3596<h5>Arguments:</h5>
3597
3598<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3599 rest of the arguments indicate the full set of possible destinations that the
3600 address may point to. Blocks are allowed to occur multiple times in the
3601 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3602
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3603<p>This destination list is required so that dataflow analysis has an accurate
3604 understanding of the CFG.</p>
3605
3606<h5>Semantics:</h5>
3607
3608<p>Control transfers to the block specified in the address argument. All
3609 possible destination blocks must be listed in the label list, otherwise this
3610 instruction has undefined behavior. This implies that jumps to labels
3611 defined in other functions have undefined behavior as well.</p>
3612
3613<h5>Implementation:</h5>
3614
3615<p>This is typically implemented with a jump through a register.</p>
3616
3617<h5>Example:</h5>
3618<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3619 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3620</pre>
3621
3622</div>
3623
3624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3625<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3626<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3627 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3628</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3629
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3630<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3632<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3633<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3634 &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]3635 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3636</pre>
3637
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3638<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3639<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640 function, with the possibility of control flow transfer to either the
3641 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3642 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3643 control flow will return to the "normal" label. If the callee (or any
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3644 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3645 instruction or other exception handling mechanism, control is interrupted and
3646 continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3647
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3648<p>The '<tt>exception</tt>' label is a
3649 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3650 exception. As such, '<tt>exception</tt>' label is required to have the
3651 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3652 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3653 happens, as its first non-PHI instruction. The restrictions on the
3654 "<tt>landingpad</tt>" instruction's tightly couples it to the
3655 "<tt>invoke</tt>" instruction, so that the important information contained
3656 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3657 code motion.</p>
3658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3659<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3660<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3661
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3662<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3664 convention</a> the call should use. If none is specified, the call
3665 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3666
3667 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3669 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3670
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3671 <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]3672 function value being invoked. In most cases, this is a direct function
3673 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3674 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3675
3676 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3678
3679 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3680 signature argument types and parameter attributes. All arguments must be
3681 of <a href="#t_firstclass">first class</a> type. If the function
3682 signature indicates the function accepts a variable number of arguments,
3683 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3684
3685 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3687
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3688 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3689 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3690 handling mechanism.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3691
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3692 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3694 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3695</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3696
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3697<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698<p>This instruction is designed to operate as a standard
3699 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3700 primary difference is that it establishes an association with a label, which
3701 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3702
3703<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3705 exception. Additionally, this is important for implementation of
3706 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3707
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3708<p>For the purposes of the SSA form, the definition of the value returned by the
3709 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3710 block to the "normal" label. If the callee unwinds then no return value is
3711 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3712
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3713<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3714<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3715 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3716 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3717 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3718 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3719</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3720
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3722
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3723 <!-- _______________________________________________________________________ -->
3724
3725<h4>
3726 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3727</h4>
3728
3729<div>
3730
3731<h5>Syntax:</h5>
3732<pre>
3733 resume &lt;type&gt; &lt;value&gt;
3734</pre>
3735
3736<h5>Overview:</h5>
3737<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3738 successors.</p>
3739
3740<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3741<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3742 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3743 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3744
3745<h5>Semantics:</h5>
3746<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3747 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3748 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3749
3750<h5>Example:</h5>
3751<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3752 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3753</pre>
3754
3755</div>
3756
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3757<!-- _______________________________________________________________________ -->
3758
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3759<h4>
3760 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3761</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3762
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3763<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3764
3765<h5>Syntax:</h5>
3766<pre>
3767 unreachable
3768</pre>
3769
3770<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3771<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3772 instruction is used to inform the optimizer that a particular portion of the
3773 code is not reachable. This can be used to indicate that the code after a
3774 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3775
3776<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3777<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3778
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3779</div>
3780
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3781</div>
3782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3783<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3784<h3>
3785 <a name="binaryops">Binary Operations</a>
3786</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3788<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789
3790<p>Binary operators are used to do most of the computation in a program. They
3791 require two operands of the same type, execute an operation on them, and
3792 produce a single value. The operands might represent multiple data, as is
3793 the case with the <a href="#t_vector">vector</a> data type. The result value
3794 has the same type as its operands.</p>
3795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3796<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3798<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3799<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3800 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3801</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3803<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3805<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3806<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3807 &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]3808 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3809 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3810 &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]3811</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3813<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3814<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3815
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3816<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817<p>The two arguments to the '<tt>add</tt>' instruction must
3818 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3819 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3820
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3821<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3822<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824<p>If the sum has unsigned overflow, the result returned is the mathematical
3825 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]3826
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827<p>Because LLVM integers use a two's complement representation, this instruction
3828 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3829
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3830<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3831 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3832 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3833 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3834 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3836<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3837<pre>
3838 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3839</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3840
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3841</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3843<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3844<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3845 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3846</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3847
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3848<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3849
3850<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3851<pre>
3852 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3853</pre>
3854
3855<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3856<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3857
3858<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3859<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3860 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3861 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3862
3863<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3864<p>The value produced is the floating point sum of the two operands.</p>
3865
3866<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3867<pre>
3868 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3869</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3870
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3871</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3872
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3873<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3874<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3875 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3876</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3878<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3879
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3880<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3881<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3882 &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]3883 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3884 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3885 &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]3886</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3887
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3888<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3889<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3891
3892<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893 '<tt>neg</tt>' instruction present in most other intermediate
3894 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3896<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897<p>The two arguments to the '<tt>sub</tt>' instruction must
3898 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3899 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3901<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3902<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3903
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3904<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3906 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3907
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908<p>Because LLVM integers use a two's complement representation, this instruction
3909 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3910
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3911<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3912 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3913 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3914 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3915 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3917<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3918<pre>
3919 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3920 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3922
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3923</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3925<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3926<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3927 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3928</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3929
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3930<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3931
3932<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3933<pre>
3934 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3935</pre>
3936
3937<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3938<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3939 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3940
3941<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3942 '<tt>fneg</tt>' instruction present in most other intermediate
3943 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3944
3945<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3946<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3947 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3948 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3949
3950<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3951<p>The value produced is the floating point difference of the two operands.</p>
3952
3953<h5>Example:</h5>
3954<pre>
3955 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3956 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3957</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3958
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3959</div>
3960
3961<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3962<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3963 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3964</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3965
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3966<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3967
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3968<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3969<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3970 &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]3971 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3972 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3973 &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]3974</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3975
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3976<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3978
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3979<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3980<p>The two arguments to the '<tt>mul</tt>' instruction must
3981 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3982 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3983
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3984<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3985<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3986
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987<p>If the result of the multiplication has unsigned overflow, the result
3988 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3989 width of the result.</p>
3990
3991<p>Because LLVM integers use a two's complement representation, and the result
3992 is the same width as the operands, this instruction returns the correct
3993 result for both signed and unsigned integers. If a full product
3994 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3995 be sign-extended or zero-extended as appropriate to the width of the full
3996 product.</p>
3997
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3998<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3999 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4000 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4001 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]4002 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4003
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4004<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4005<pre>
4006 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4007</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4008
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4009</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4010
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4011<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4012<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4013 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4014</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4015
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4016<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4017
4018<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019<pre>
4020 &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]4021</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4022
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4023<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4025
4026<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4027<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4029 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4030
4031<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4032<p>The value produced is the floating point product of the two operands.</p>
4033
4034<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4035<pre>
4036 &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]4037</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4038
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4039</div>
4040
4041<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4042<h4>
4043 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4044</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4046<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4047
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4048<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4050 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4051 &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]4052</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4053
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4056
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4057<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4058<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4059 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4060 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4061
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4062<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4063<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4064
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4065<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4067
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4068<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4069
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4070<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4071 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4072 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4073
4074
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4075<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076<pre>
4077 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4078</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4079
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4080</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4082<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4083<h4>
4084 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4085</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4087<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4088
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4089<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4090<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4091 &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]4092 &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]4093</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4094
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4095<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4097
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4098<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4099<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4100 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4101 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4102
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4103<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4104<p>The value produced is the signed integer quotient of the two operands rounded
4105 towards zero.</p>
4106
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4107<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4108 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4109
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4110<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4111 undefined behavior; this is a rare case, but can occur, for example, by doing
4112 a 32-bit division of -2147483648 by -1.</p>
4113
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]4114<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4115 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]4116 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4117
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4118<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119<pre>
4120 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4121</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4122
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4123</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4125<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4126<h4>
4127 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4128</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4130<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4131
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4132<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4133<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4134 &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]4135</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4137<h5>Overview:</h5>
4138<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4139
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4140<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4141<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4142 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4143 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4144
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4145<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4146<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4147
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4148<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4149<pre>
4150 &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]4151</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4152
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4153</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4154
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4155<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4156<h4>
4157 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4158</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4160<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4161
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4162<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163<pre>
4164 &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]4165</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4166
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4167<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4168<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4169 division of its two arguments.</p>
4170
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4171<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4172<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4173 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4174 values. Both arguments must have identical types.</p>
4175
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4176<h5>Semantics:</h5>
4177<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178 This instruction always performs an unsigned division to get the
4179 remainder.</p>
4180
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4181<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4183
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4184<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4185
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4186<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4187<pre>
4188 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4189</pre>
4190
4191</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4193<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4194<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4195 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4196</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4197
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4198<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4199
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4200<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4201<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4202 &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]4203</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4204
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4205<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4207 division of its two operands. This instruction can also take
4208 <a href="#t_vector">vector</a> versions of the values in which case the
4209 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]4210
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4211<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4212<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4213 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4214 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4215
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4216<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4217<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4218 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4219 <i>modulo</i> operator (where the result is either zero or has the same sign
4220 as the divisor, <tt>op2</tt>) of a value.
4221 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4223 Math Forum</a>. For a table of how this is implemented in various languages,
4224 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4225 Wikipedia: modulo operation</a>.</p>
4226
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4227<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4229
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4230<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231 Overflow also leads to undefined behavior; this is a rare case, but can
4232 occur, for example, by taking the remainder of a 32-bit division of
4233 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4234 lets srem be implemented using instructions that return both the result of
4235 the division and the remainder.)</p>
4236
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4237<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4238<pre>
4239 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4240</pre>
4241
4242</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4243
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4244<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4245<h4>
4246 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4247</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4248
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4249<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4250
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4251<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4252<pre>
4253 &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]4254</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4255
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4256<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4257<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4258 its two operands.</p>
4259
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4260<h5>Arguments:</h5>
4261<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4262 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4263 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4264
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4265<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266<p>This instruction returns the <i>remainder</i> of a division. The remainder
4267 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4268
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4269<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4270<pre>
4271 &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]4272</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4273
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4274</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4275
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4276</div>
4277
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4278<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4279<h3>
4280 <a name="bitwiseops">Bitwise Binary Operations</a>
4281</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4283<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284
4285<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4286 program. They are generally very efficient instructions and can commonly be
4287 strength reduced from other instructions. They require two operands of the
4288 same type, execute an operation on them, and produce a single value. The
4289 resulting value is the same type as its operands.</p>
4290
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4291<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4292<h4>
4293 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4294</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4295
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4296<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4297
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4298<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4299<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4300 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4301 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4302 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4303 &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]4304</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4305
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4306<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4307<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4308 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4309
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4310<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4312 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4313 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4314
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4315<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4317 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4318 is (statically or dynamically) negative or equal to or larger than the number
4319 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4320 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4321 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4322
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4323<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4324 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4325 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4326 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4327 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4328 they would if the shift were expressed as a mul instruction with the same
4329 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4330
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331<h5>Example:</h5>
4332<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4333 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4334 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4335 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4336 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4337 &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]4338</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4340</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4342<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4343<h4>
4344 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4345</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4347<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4349<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4350<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4351 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4352 &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]4353</pre>
4354
4355<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4356<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4357 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4358
4359<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4360<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4361 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4362 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4363
4364<h5>Semantics:</h5>
4365<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366 significant bits of the result will be filled with zero bits after the shift.
4367 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4368 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4369 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4370 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4371
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4372<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4373 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4374 shifted out are non-zero.</p>
4375
4376
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4377<h5>Example:</h5>
4378<pre>
4379 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4380 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4381 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4382 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4383 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4384 &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]4385</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4386
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4387</div>
4388
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4389<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4390<h4>
4391 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4392</h4>
4393
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4394<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4395
4396<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4398 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4399 &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]4400</pre>
4401
4402<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4404 operand shifted to the right a specified number of bits with sign
4405 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4406
4407<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4408<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4409 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4410 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4411
4412<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4413<p>This instruction always performs an arithmetic shift right operation, The
4414 most significant bits of the result will be filled with the sign bit
4415 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4416 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4417 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4418 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4419
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4420<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4421 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4422 shifted out are non-zero.</p>
4423
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4424<h5>Example:</h5>
4425<pre>
4426 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4427 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4428 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4429 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4430 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4431 &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]4432</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4434</div>
4435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4436<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4437<h4>
4438 <a name="i_and">'<tt>and</tt>' Instruction</a>
4439</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4440
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4441<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4442
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4443<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4444<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4445 &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]4446</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4448<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4449<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4450 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4451
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4452<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4453<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4455 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4456
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4457<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4458<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4460<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4461 <tbody>
4462 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4463 <th>In0</th>
4464 <th>In1</th>
4465 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4466 </tr>
4467 <tr>
4468 <td>0</td>
4469 <td>0</td>
4470 <td>0</td>
4471 </tr>
4472 <tr>
4473 <td>0</td>
4474 <td>1</td>
4475 <td>0</td>
4476 </tr>
4477 <tr>
4478 <td>1</td>
4479 <td>0</td>
4480 <td>0</td>
4481 </tr>
4482 <tr>
4483 <td>1</td>
4484 <td>1</td>
4485 <td>1</td>
4486 </tr>
4487 </tbody>
4488</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4490<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4491<pre>
4492 &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]4493 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4494 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4495</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4496</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4497<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4498<h4>
4499 <a name="i_or">'<tt>or</tt>' Instruction</a>
4500</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4501
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4502<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503
4504<h5>Syntax:</h5>
4505<pre>
4506 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4507</pre>
4508
4509<h5>Overview:</h5>
4510<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4511 two operands.</p>
4512
4513<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4514<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4515 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4516 values. Both arguments must have identical types.</p>
4517
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4518<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4519<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4520
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4521<table border="1" cellspacing="0" cellpadding="4">
4522 <tbody>
4523 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4524 <th>In0</th>
4525 <th>In1</th>
4526 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4527 </tr>
4528 <tr>
4529 <td>0</td>
4530 <td>0</td>
4531 <td>0</td>
4532 </tr>
4533 <tr>
4534 <td>0</td>
4535 <td>1</td>
4536 <td>1</td>
4537 </tr>
4538 <tr>
4539 <td>1</td>
4540 <td>0</td>
4541 <td>1</td>
4542 </tr>
4543 <tr>
4544 <td>1</td>
4545 <td>1</td>
4546 <td>1</td>
4547 </tr>
4548 </tbody>
4549</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4550
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4551<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4552<pre>
4553 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4554 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4555 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4556</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4557
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4558</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4560<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4561<h4>
4562 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4563</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4565<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4567<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568<pre>
4569 &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]4570</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4572<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4573<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4574 its two operands. The <tt>xor</tt> is used to implement the "one's
4575 complement" operation, which is the "~" operator in C.</p>
4576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4577<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4578<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4580 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4582<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4583<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4584
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4585<table border="1" cellspacing="0" cellpadding="4">
4586 <tbody>
4587 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4588 <th>In0</th>
4589 <th>In1</th>
4590 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4591 </tr>
4592 <tr>
4593 <td>0</td>
4594 <td>0</td>
4595 <td>0</td>
4596 </tr>
4597 <tr>
4598 <td>0</td>
4599 <td>1</td>
4600 <td>1</td>
4601 </tr>
4602 <tr>
4603 <td>1</td>
4604 <td>0</td>
4605 <td>1</td>
4606 </tr>
4607 <tr>
4608 <td>1</td>
4609 <td>1</td>
4610 <td>0</td>
4611 </tr>
4612 </tbody>
4613</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4615<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4616<pre>
4617 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4618 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4619 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4620 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4621</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4623</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4624
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4625</div>
4626
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4627<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4628<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4629 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4630</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4631
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4632<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4633
4634<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4635 target-independent manner. These instructions cover the element-access and
4636 vector-specific operations needed to process vectors effectively. While LLVM
4637 does directly support these vector operations, many sophisticated algorithms
4638 will want to use target-specific intrinsics to take full advantage of a
4639 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4640
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4641<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4642<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4643 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4644</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4645
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4646<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4647
4648<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4649<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4650 &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]4651</pre>
4652
4653<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4655 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4656
4657
4658<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4660 of <a href="#t_vector">vector</a> type. The second operand is an index
4661 indicating the position from which to extract the element. The index may be
4662 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4663
4664<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665<p>The result is a scalar of the same type as the element type of
4666 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4667 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4668 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4669
4670<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4671<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4672 &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]4673</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4674
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4676
4677<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4678<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4679 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4680</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4682<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4683
4684<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4685<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4686 &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]4687</pre>
4688
4689<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4690<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4691 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4692
4693<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4694<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4695 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4696 whose type must equal the element type of the first operand. The third
4697 operand is an index indicating the position at which to insert the value.
4698 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4699
4700<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4701<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4702 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4703 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4704 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4705
4706<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4707<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4708 &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]4709</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4711</div>
4712
4713<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4714<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4715 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4716</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4718<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4719
4720<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4721<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4722 &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]4723</pre>
4724
4725<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4726<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4727 from two input vectors, returning a vector with the same element type as the
4728 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4729
4730<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4732 with types that match each other. The third argument is a shuffle mask whose
4733 element type is always 'i32'. The result of the instruction is a vector
4734 whose length is the same as the shuffle mask and whose element type is the
4735 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4736
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4737<p>The shuffle mask operand is required to be a constant vector with either
4738 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4739
4740<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741<p>The elements of the two input vectors are numbered from left to right across
4742 both of the vectors. The shuffle mask operand specifies, for each element of
4743 the result vector, which element of the two input vectors the result element
4744 gets. The element selector may be undef (meaning "don't care") and the
4745 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4746
4747<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4748<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4749 &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]4750 &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]4751 &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]4752 &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]4753 &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]4754 &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]4755 &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]4756 &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]4757</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4759</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4760
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4761</div>
4762
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4763<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4764<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4765 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4766</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4767
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4768<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4769
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4770<p>LLVM supports several instructions for working with
4771 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4772
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4773<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4774<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4775 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4776</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4777
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4778<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4779
4780<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4781<pre>
4782 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4783</pre>
4784
4785<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4786<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4787 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4788
4789<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4790<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4791 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4792 <a href="#t_array">array</a> type. The operands are constant indices to
4793 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4794 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4795 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4796 <ul>
4797 <li>Since the value being indexed is not a pointer, the first index is
4798 omitted and assumed to be zero.</li>
4799 <li>At least one index must be specified.</li>
4800 <li>Not only struct indices but also array indices must be in
4801 bounds.</li>
4802 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4803
4804<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4805<p>The result is the value at the position in the aggregate specified by the
4806 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4807
4808<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4809<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4810 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4811</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4812
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4814
4815<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4816<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4817 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4818</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4819
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4820<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4821
4822<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4823<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4824 &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]4825</pre>
4826
4827<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4828<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4829 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4830
4831<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4832<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4833 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4834 <a href="#t_array">array</a> type. The second operand is a first-class
4835 value to insert. The following operands are constant indices indicating
4836 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]4837 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4838 value to insert must have the same type as the value identified by the
4839 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4840
4841<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4843 that of <tt>val</tt> except that the value at the position specified by the
4844 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4845
4846<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4847<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4848 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4849 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4850 %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]4851</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4852
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4853</div>
4854
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4855</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4856
4857<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4858<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4859 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4860</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4861
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4862<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4864<p>A key design point of an SSA-based representation is how it represents
4865 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4866 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4867 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4869<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4870<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4871 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4872</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4873
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4874<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4876<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4877<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4878 &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]4879</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4881<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4882<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883 currently executing function, to be automatically released when this function
4884 returns to its caller. The object is always allocated in the generic address
4885 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4886
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4887<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>alloca</tt>' instruction
4889 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4890 runtime stack, returning a pointer of the appropriate type to the program.
4891 If "NumElements" is specified, it is the number of elements allocated,
4892 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4893 specified, the value result of the allocation is guaranteed to be aligned to
4894 at least that boundary. If not specified, or if zero, the target can choose
4895 to align the allocation on any convenient boundary compatible with the
4896 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4897
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4898<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4899
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4900<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4901<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4902 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4903 memory is automatically released when the function returns. The
4904 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4905 variables that must have an address available. When the function returns
4906 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]4907 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4908 reclaimed. Allocating zero bytes is legal, but the result is undefined.
4909 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewycky75d05e62012-03-18 09:35:50 +0000[diff] [blame]4910 not specified.</p>
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4911
4912<p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4914<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4915<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4916 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4917 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4918 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4919 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4920</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4921
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4922</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4923
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4924<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4925<h4>
4926 <a name="i_load">'<tt>load</tt>' Instruction</a>
4927</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4928
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4929<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4930
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4931<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4932<pre>
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4933 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;][, !invariant.load !&lt;index&gt;]
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4934 &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]4935 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4936</pre>
4937
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4938<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4939<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4940
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4941<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4942<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4943 from which to load. The pointer must point to
4944 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4945 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4946 number or order of execution of this <tt>load</tt> with other <a
4947 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4948
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4949<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4950 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4951 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4952 not valid on <code>load</code> instructions. Atomic loads produce <a
4953 href="#memorymodel">defined</a> results when they may see multiple atomic
4954 stores. The type of the pointee must be an integer type whose bit width
4955 is a power of two greater than or equal to eight and less than or equal
4956 to a target-specific size limit. <code>align</code> must be explicitly
4957 specified on atomic loads, and the load has undefined behavior if the
4958 alignment is not set to a value which is at least the size in bytes of
4959 the pointee. <code>!nontemporal</code> does not have any defined semantics
4960 for atomic loads.</p>
4961
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4962<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4963 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]4964 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4965 alignment for the target. It is the responsibility of the code emitter to
4966 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4967 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4968 produce less efficient code. An alignment of 1 is always safe.</p>
4969
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4970<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4971 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4972 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4973 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4974 and code generator that this load is not expected to be reused in the cache.
4975 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4976 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4977
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4978<p>The optional <tt>!invariant.load</tt> metadata must reference a single
4979 metatadata name &lt;index&gt; corresponding to a metadata node with no
4980 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
4981 instruction tells the optimizer and code generator that this load address
4982 points to memory which does not change value during program execution.
4983 The optimizer may then move this load around, for example, by hoisting it
4984 out of loops using loop invariant code motion.</p>
4985
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4986<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4987<p>The location of memory pointed to is loaded. If the value being loaded is of
4988 scalar type then the number of bytes read does not exceed the minimum number
4989 of bytes needed to hold all bits of the type. For example, loading an
4990 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4991 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4992 is undefined if the value was not originally written using a store of the
4993 same type.</p>
4994
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4995<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4996<pre>
4997 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4998 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4999 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5000</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5001
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5002</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5003
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5004<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5005<h4>
5006 <a name="i_store">'<tt>store</tt>' Instruction</a>
5007</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5008
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5009<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5010
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5011<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5013 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>
5014 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]5015</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5017<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5018<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5020<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5022 and an address at which to store it. The type of the
5023 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5024 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]5025 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5026 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5027 order of execution of this <tt>store</tt> with other <a
5028 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5029
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]5030<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5031 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5032 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5033 valid on <code>store</code> instructions. Atomic loads produce <a
5034 href="#memorymodel">defined</a> results when they may see multiple atomic
5035 stores. The type of the pointee must be an integer type whose bit width
5036 is a power of two greater than or equal to eight and less than or equal
5037 to a target-specific size limit. <code>align</code> must be explicitly
5038 specified on atomic stores, and the store has undefined behavior if the
5039 alignment is not set to a value which is at least the size in bytes of
5040 the pointee. <code>!nontemporal</code> does not have any defined semantics
5041 for atomic stores.</p>
5042
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043<p>The optional constant "align" argument specifies the alignment of the
5044 operation (that is, the alignment of the memory address). A value of 0 or an
5045 omitted "align" argument means that the operation has the preferential
5046 alignment for the target. It is the responsibility of the code emitter to
5047 ensure that the alignment information is correct. Overestimating the
5048 alignment results in an undefined behavior. Underestimating the alignment may
5049 produce less efficient code. An alignment of 1 is always safe.</p>
5050
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5051<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5052 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5053 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5054 instruction tells the optimizer and code generator that this load is
5055 not expected to be reused in the cache. The code generator may
5056 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5057 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5058
5059
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5060<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5061<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5062 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5063 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5064 does not exceed the minimum number of bytes needed to hold all bits of the
5065 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5066 writing a value of a type like <tt>i20</tt> with a size that is not an
5067 integral number of bytes, it is unspecified what happens to the extra bits
5068 that do not belong to the type, but they will typically be overwritten.</p>
5069
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5070<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071<pre>
5072 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]5073 store i32 3, i32* %ptr <i>; yields {void}</i>
5074 %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]5075</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5077</div>
5078
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5079<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5080<h4>
5081<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5082</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5083
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5084<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5085
5086<h5>Syntax:</h5>
5087<pre>
5088 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5089</pre>
5090
5091<h5>Overview:</h5>
5092<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5093between operations.</p>
5094
5095<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5096href="#ordering">ordering</a> argument which defines what
5097<i>synchronizes-with</i> edges they add. They can only be given
5098<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5099<code>seq_cst</code> orderings.</p>
5100
5101<h5>Semantics:</h5>
5102<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5103semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5104<code>acquire</code> ordering semantics if and only if there exist atomic
5105operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5106<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5107<var>X</var> modifies <var>M</var> (either directly or through some side effect
5108of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5109<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5110<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5111than an explicit <code>fence</code>, one (but not both) of the atomic operations
5112<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5113<code>acquire</code> (resp.) ordering constraint and still
5114<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5115<i>happens-before</i> edge.</p>
5116
5117<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5118having both <code>acquire</code> and <code>release</code> semantics specified
5119above, participates in the global program order of other <code>seq_cst</code>
5120operations and/or fences.</p>
5121
5122<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5123specifies that the fence only synchronizes with other fences in the same
5124thread. (This is useful for interacting with signal handlers.)</p>
5125
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5126<h5>Example:</h5>
5127<pre>
5128 fence acquire <i>; yields {void}</i>
5129 fence singlethread seq_cst <i>; yields {void}</i>
5130</pre>
5131
5132</div>
5133
5134<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5135<h4>
5136<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5137</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5138
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5139<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5140
5141<h5>Syntax:</h5>
5142<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5143 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]5144</pre>
5145
5146<h5>Overview:</h5>
5147<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5148It loads a value in memory and compares it to a given value. If they are
5149equal, it stores a new value into the memory.</p>
5150
5151<h5>Arguments:</h5>
5152<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5153address to operate on, a value to compare to the value currently be at that
5154address, and a new value to place at that address if the compared values are
5155equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5156bit width is a power of two greater than or equal to eight and less than
5157or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5158'<var>&lt;new&gt;</var>' must have the same type, and the type of
5159'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5160<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5161optimizer is not allowed to modify the number or order of execution
5162of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5163operations</a>.</p>
5164
5165<!-- FIXME: Extend allowed types. -->
5166
5167<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5168<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5169
5170<p>The optional "<code>singlethread</code>" argument declares that the
5171<code>cmpxchg</code> is only atomic with respect to code (usually signal
5172handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5173cmpxchg is atomic with respect to all other code in the system.</p>
5174
5175<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5176the size in memory of the operand.
5177
5178<h5>Semantics:</h5>
5179<p>The contents of memory at the location specified by the
5180'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5181'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5182'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5183is returned.
5184
5185<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5186purpose of identifying <a href="#release_sequence">release sequences</a>. A
5187failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5188parameter determined by dropping any <code>release</code> part of the
5189<code>cmpxchg</code>'s ordering.</p>
5190
5191<!--
5192FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5193optimization work on ARM.)
5194
5195FIXME: Is a weaker ordering constraint on failure helpful in practice?
5196-->
5197
5198<h5>Example:</h5>
5199<pre>
5200entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5201 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5202 <a href="#i_br">br</a> label %loop
5203
5204loop:
5205 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5206 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5207 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5208 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5209 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5210
5211done:
5212 ...
5213</pre>
5214
5215</div>
5216
5217<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5218<h4>
5219<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5220</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5221
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5222<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5223
5224<h5>Syntax:</h5>
5225<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5226 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]5227</pre>
5228
5229<h5>Overview:</h5>
5230<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5231
5232<h5>Arguments:</h5>
5233<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5234operation to apply, an address whose value to modify, an argument to the
5235operation. The operation must be one of the following keywords:</p>
5236<ul>
5237 <li>xchg</li>
5238 <li>add</li>
5239 <li>sub</li>
5240 <li>and</li>
5241 <li>nand</li>
5242 <li>or</li>
5243 <li>xor</li>
5244 <li>max</li>
5245 <li>min</li>
5246 <li>umax</li>
5247 <li>umin</li>
5248</ul>
5249
5250<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5251bit width is a power of two greater than or equal to eight and less than
5252or equal to a target-specific size limit. The type of the
5253'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5254If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5255optimizer is not allowed to modify the number or order of execution of this
5256<code>atomicrmw</code> with other <a href="#volatile">volatile
5257 operations</a>.</p>
5258
5259<!-- FIXME: Extend allowed types. -->
5260
5261<h5>Semantics:</h5>
5262<p>The contents of memory at the location specified by the
5263'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5264back. The original value at the location is returned. The modification is
5265specified by the <var>operation</var> argument:</p>
5266
5267<ul>
5268 <li>xchg: <code>*ptr = val</code></li>
5269 <li>add: <code>*ptr = *ptr + val</code></li>
5270 <li>sub: <code>*ptr = *ptr - val</code></li>
5271 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5272 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5273 <li>or: <code>*ptr = *ptr | val</code></li>
5274 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5275 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5276 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5277 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5278 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5279</ul>
5280
5281<h5>Example:</h5>
5282<pre>
5283 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5284</pre>
5285
5286</div>
5287
5288<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5289<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5290 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5291</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5292
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5293<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5294
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5295<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5296<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5297 &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]5298 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5299 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5300</pre>
5301
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5302<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5303<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5304 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5305 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5306
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5307<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5308<p>The first argument is always a pointer or a vector of pointers,
5309 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5310 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5311 elements of the aggregate object are indexed. The interpretation of each
5312 index is dependent on the type being indexed into. The first index always
5313 indexes the pointer value given as the first argument, the second index
5314 indexes a value of the type pointed to (not necessarily the value directly
5315 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5316 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5317 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5318 can never be pointers, since that would require loading the pointer before
5319 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5320
5321<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]5322 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5323 integer <b>constants</b> are allowed. When indexing into an array, pointer
5324 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]5325 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5327<p>For example, let's consider a C code fragment and how it gets compiled to
5328 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5329
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5330<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5331struct RT {
5332 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5333 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5334 char C;
5335};
5336struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5337 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5338 double Y;
5339 struct RT Z;
5340};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5341
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5342int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5343 return &amp;s[1].Z.B[5][13];
5344}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5345</pre>
5346
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5347<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5348
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5349<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5350%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5351%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5352
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5353define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5354entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5355 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5356 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5357}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5358</pre>
5359
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5360<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5361<p>In the example above, the first index is indexing into the
5362 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5363 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5364 structure. The second index indexes into the third element of the structure,
5365 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5366 type, another structure. The third index indexes into the second element of
5367 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5368 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5369 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5370 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5371
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5372<p>Note that it is perfectly legal to index partially through a structure,
5373 returning a pointer to an inner element. Because of this, the LLVM code for
5374 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5375
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5376<pre class="doc_code">
5377define i32* @foo(%struct.ST* %s) {
5378 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5379 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5380 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5381 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5382 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5383 ret i32* %t5
5384}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5385</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5386
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5387<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5388 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5389 base pointer is not an <i>in bounds</i> address of an allocated object,
5390 or if any of the addresses that would be formed by successive addition of
5391 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5392 precise signed arithmetic are not an <i>in bounds</i> address of that
5393 allocated object. The <i>in bounds</i> addresses for an allocated object
5394 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5395 byte past the end.
5396 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5397 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5398
5399<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]5400 the base address with silently-wrapping two's complement arithmetic. If the
5401 offsets have a different width from the pointer, they are sign-extended or
5402 truncated to the width of the pointer. The result value of the
5403 <tt>getelementptr</tt> may be outside the object pointed to by the base
5404 pointer. The result value may not necessarily be used to access memory
5405 though, even if it happens to point into allocated storage. See the
5406 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5407 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5408
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5409<p>The getelementptr instruction is often confusing. For some more insight into
5410 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5411
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5412<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5413<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5414 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5415 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5416 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5417 %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]5418 <i>; yields i8*:eptr</i>
5419 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5420 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5421 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5422</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5423
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5424<p>In cases where the pointer argument is a vector of pointers, only a
5425 single index may be used, and the number of vector elements has to be
5426 the same. For example: </p>
5427<pre class="doc_code">
5428 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5429</pre>
5430
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5431</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5432
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5433</div>
5434
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5435<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5436<h3>
5437 <a name="convertops">Conversion Operations</a>
5438</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5439
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5440<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5441
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5442<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5443 which all take a single operand and a type. They perform various bit
5444 conversions on the operand.</p>
5445
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5446<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5447<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5448 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5449</h4>
5450
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5451<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5452
5453<h5>Syntax:</h5>
5454<pre>
5455 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5456</pre>
5457
5458<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5459<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5460 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5461
5462<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5463<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5464 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5465 of the same number of integers.
5466 The bit size of the <tt>value</tt> must be larger than
5467 the bit size of the destination type, <tt>ty2</tt>.
5468 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5469
5470<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5471<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5472 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5473 source size must be larger than the destination size, <tt>trunc</tt> cannot
5474 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5475
5476<h5>Example:</h5>
5477<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5478 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5479 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5480 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5481 %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]5482</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5483
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5484</div>
5485
5486<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5487<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5488 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5489</h4>
5490
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5491<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5492
5493<h5>Syntax:</h5>
5494<pre>
5495 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5496</pre>
5497
5498<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5499<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5501
5502
5503<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5504<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5505 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5506 of the same number of integers.
5507 The bit size of the <tt>value</tt> must be smaller than
5508 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5509 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5510
5511<h5>Semantics:</h5>
5512<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]5513 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5514
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5515<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]5516
5517<h5>Example:</h5>
5518<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5519 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5520 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5521 %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]5522</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5523
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5524</div>
5525
5526<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5527<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5528 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5529</h4>
5530
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5531<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5532
5533<h5>Syntax:</h5>
5534<pre>
5535 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5536</pre>
5537
5538<h5>Overview:</h5>
5539<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5540
5541<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5542<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5543 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5544 of the same number of integers.
5545 The bit size of the <tt>value</tt> must be smaller than
5546 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5547 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5548
5549<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5550<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5551 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5552 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5553
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5554<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]5555
5556<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5557<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5558 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5559 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5560 %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]5561</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5563</div>
5564
5565<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5566<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5567 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5568</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5569
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5570<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5571
5572<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5573<pre>
5574 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5575</pre>
5576
5577<h5>Overview:</h5>
5578<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5579 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5580
5581<h5>Arguments:</h5>
5582<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5583 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5584 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]5585 <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]5586 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5587
5588<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5589<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5590 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591 <a href="#t_floating">floating point</a> type. If the value cannot fit
5592 within the destination type, <tt>ty2</tt>, then the results are
5593 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5594
5595<h5>Example:</h5>
5596<pre>
5597 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5598 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5599</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5600
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5601</div>
5602
5603<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5604<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5605 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5606</h4>
5607
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5608<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5609
5610<h5>Syntax:</h5>
5611<pre>
5612 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5613</pre>
5614
5615<h5>Overview:</h5>
5616<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]5617 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5618
5619<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5620<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5621 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5622 a <a href="#t_floating">floating point</a> type to cast it to. The source
5623 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5624
5625<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5626<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5627 <a href="#t_floating">floating point</a> type to a larger
5628 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5629 used to make a <i>no-op cast</i> because it always changes bits. Use
5630 <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]5631
5632<h5>Example:</h5>
5633<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5634 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5635 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5636</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5637
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5638</div>
5639
5640<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5641<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5642 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5643</h4>
5644
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5645<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5646
5647<h5>Syntax:</h5>
5648<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5649 &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]5650</pre>
5651
5652<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5653<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5654 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5655
5656<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5657<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5658 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5659 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5660 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5661 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5662
5663<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5664<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5666 towards zero) unsigned integer value. If the value cannot fit
5667 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5668
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5669<h5>Example:</h5>
5670<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5671 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5672 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5673 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5674</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5675
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5676</div>
5677
5678<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5679<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5680 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5681</h4>
5682
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5683<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5684
5685<h5>Syntax:</h5>
5686<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5687 &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]5688</pre>
5689
5690<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5691<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5692 <a href="#t_floating">floating point</a> <tt>value</tt> to
5693 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5694
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5695<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5696<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5697 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5698 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5699 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5700 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5701
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5702<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5703<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5704 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5705 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5706 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5707
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5708<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5709<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5710 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5711 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5712 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5713</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5715</div>
5716
5717<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5718<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5719 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5720</h4>
5721
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5722<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5723
5724<h5>Syntax:</h5>
5725<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5726 &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]5727</pre>
5728
5729<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5730<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5731 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5732
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5733<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5734<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]5735 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5736 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5737 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5738 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5739
5740<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5741<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5742 integer quantity and converts it to the corresponding floating point
5743 value. If the value cannot fit in the floating point value, the results are
5744 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5745
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5746<h5>Example:</h5>
5747<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5748 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5749 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5750</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5751
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5752</div>
5753
5754<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5755<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5756 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5757</h4>
5758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5759<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5760
5761<h5>Syntax:</h5>
5762<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5763 &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]5764</pre>
5765
5766<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5768 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5769
5770<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5771<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]5772 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5773 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5774 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5775 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5776
5777<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5778<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5779 quantity and converts it to the corresponding floating point value. If the
5780 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5781
5782<h5>Example:</h5>
5783<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5784 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5785 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5786</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5787
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5788</div>
5789
5790<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5791<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5792 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5793</h4>
5794
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5795<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5796
5797<h5>Syntax:</h5>
5798<pre>
5799 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5800</pre>
5801
5802<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5803<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5804 pointers <tt>value</tt> to
5805 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5806
5807<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5809 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5810 pointers, and a type to cast it to
5811 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5812 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5813
5814<h5>Semantics:</h5>
5815<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5816 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5817 truncating or zero extending that value to the size of the integer type. If
5818 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5819 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5820 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5821 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5822
5823<h5>Example:</h5>
5824<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5825 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5826 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5827 %Z = ptrtoint &lt;4 x i32*&gt; %P to &lt;4 x i64&gt;<i>; yields vector zero extension for a vector of addresses on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5828</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5829
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5830</div>
5831
5832<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5833<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5834 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5835</h4>
5836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5837<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5838
5839<h5>Syntax:</h5>
5840<pre>
5841 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5842</pre>
5843
5844<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5845<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5846 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5847
5848<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5849<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5850 value to cast, and a type to cast it to, which must be a
5851 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5852
5853<h5>Semantics:</h5>
5854<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5856 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5857 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5858 than the size of a pointer then a zero extension is done. If they are the
5859 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5860
5861<h5>Example:</h5>
5862<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5863 %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]5864 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5865 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5866 %Z = inttoptr &lt;4 x i32&gt; %G to &lt;4 x i8*&gt;<i>; yields truncation of vector G to four pointers</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5868
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5869</div>
5870
5871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5872<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5873 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5874</h4>
5875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5876<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5877
5878<h5>Syntax:</h5>
5879<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5880 &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]5881</pre>
5882
5883<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5884<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5885 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5886
5887<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5888<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5889 non-aggregate first class value, and a type to cast it to, which must also be
5890 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5891 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5892 identical. If the source type is a pointer, the destination type must also be
5893 a pointer. This instruction supports bitwise conversion of vectors to
5894 integers and to vectors of other types (as long as they have the same
5895 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5896
5897<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5898<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5899 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5900 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5901 stored to memory and read back as type <tt>ty2</tt>.
5902 Pointer (or vector of pointers) types may only be converted to other pointer
5903 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5904 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5905 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5906
5907<h5>Example:</h5>
5908<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5909 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5910 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5911 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5912 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5913</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5915</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5916
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5917</div>
5918
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5919<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5920<h3>
5921 <a name="otherops">Other Operations</a>
5922</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5923
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5924<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5925
5926<p>The instructions in this category are the "miscellaneous" instructions, which
5927 defy better classification.</p>
5928
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5929<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5930<h4>
5931 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5932</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5933
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5934<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5935
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5936<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5937<pre>
5938 &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]5939</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5940
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5941<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5943 boolean values based on comparison of its two integer, integer vector,
5944 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5945
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5946<h5>Arguments:</h5>
5947<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5948 the condition code indicating the kind of comparison to perform. It is not a
5949 value, just a keyword. The possible condition code are:</p>
5950
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5951<ol>
5952 <li><tt>eq</tt>: equal</li>
5953 <li><tt>ne</tt>: not equal </li>
5954 <li><tt>ugt</tt>: unsigned greater than</li>
5955 <li><tt>uge</tt>: unsigned greater or equal</li>
5956 <li><tt>ult</tt>: unsigned less than</li>
5957 <li><tt>ule</tt>: unsigned less or equal</li>
5958 <li><tt>sgt</tt>: signed greater than</li>
5959 <li><tt>sge</tt>: signed greater or equal</li>
5960 <li><tt>slt</tt>: signed less than</li>
5961 <li><tt>sle</tt>: signed less or equal</li>
5962</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5963
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5964<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5966 typed. They must also be identical types.</p>
5967
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5968<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5969<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5970 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5971 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]5972 result, as follows:</p>
5973
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5974<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5975 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5976 <tt>false</tt> otherwise. No sign interpretation is necessary or
5977 performed.</li>
5978
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5979 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5980 <tt>false</tt> otherwise. No sign interpretation is necessary or
5981 performed.</li>
5982
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5983 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5984 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5985
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5986 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5987 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5988 to <tt>op2</tt>.</li>
5989
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5990 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5992
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5993 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5994 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5995
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5996 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5997 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5998
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5999 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6001 to <tt>op2</tt>.</li>
6002
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6003 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6005
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6006 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007 <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]6008</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6009
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6010<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011 values are compared as if they were integers.</p>
6012
6013<p>If the operands are integer vectors, then they are compared element by
6014 element. The result is an <tt>i1</tt> vector with the same number of elements
6015 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6016
6017<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6018<pre>
6019 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6020 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6021 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6022 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6023 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6024 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6025</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6026
6027<p>Note that the code generator does not yet support vector types with
6028 the <tt>icmp</tt> instruction.</p>
6029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6030</div>
6031
6032<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6033<h4>
6034 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6035</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6036
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6037<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6039<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6040<pre>
6041 &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]6042</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6045<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6046 values based on comparison of its operands.</p>
6047
6048<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]6049(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6050
6051<p>If the operands are floating point vectors, then the result type is a vector
6052 of boolean with the same number of elements as the operands being
6053 compared.</p>
6054
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6055<h5>Arguments:</h5>
6056<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6057 the condition code indicating the kind of comparison to perform. It is not a
6058 value, just a keyword. The possible condition code are:</p>
6059
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6060<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6061 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6062 <li><tt>oeq</tt>: ordered and equal</li>
6063 <li><tt>ogt</tt>: ordered and greater than </li>
6064 <li><tt>oge</tt>: ordered and greater than or equal</li>
6065 <li><tt>olt</tt>: ordered and less than </li>
6066 <li><tt>ole</tt>: ordered and less than or equal</li>
6067 <li><tt>one</tt>: ordered and not equal</li>
6068 <li><tt>ord</tt>: ordered (no nans)</li>
6069 <li><tt>ueq</tt>: unordered or equal</li>
6070 <li><tt>ugt</tt>: unordered or greater than </li>
6071 <li><tt>uge</tt>: unordered or greater than or equal</li>
6072 <li><tt>ult</tt>: unordered or less than </li>
6073 <li><tt>ule</tt>: unordered or less than or equal</li>
6074 <li><tt>une</tt>: unordered or not equal</li>
6075 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6076 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6077</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6079<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6080 <i>unordered</i> means that either operand may be a QNAN.</p>
6081
6082<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6083 a <a href="#t_floating">floating point</a> type or
6084 a <a href="#t_vector">vector</a> of floating point type. They must have
6085 identical types.</p>
6086
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6087<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]6088<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6089 according to the condition code given as <tt>cond</tt>. If the operands are
6090 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6091 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6092 follows:</p>
6093
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6094<ol>
6095 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6096
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6097 <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]6098 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6099
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6100 <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]6101 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6102
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6103 <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]6104 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6105
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6106 <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]6107 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6108
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6109 <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]6110 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6111
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6112 <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]6113 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6114
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6115 <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]6116
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6117 <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]6118 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6119
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6120 <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]6121 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6122
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6123 <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]6124 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6125
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6126 <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]6127 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6128
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6129 <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]6130 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6131
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6132 <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]6133 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6134
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6135 <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]6136
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6137 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6138</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6139
6140<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6141<pre>
6142 &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]6143 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6144 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6145 &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]6146</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6147
6148<p>Note that the code generator does not yet support vector types with
6149 the <tt>fcmp</tt> instruction.</p>
6150
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6151</div>
6152
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6153<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6154<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6155 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6156</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6157
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6158<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6159
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6160<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6161<pre>
6162 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6163</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6164
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6165<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6166<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6167 SSA graph representing the function.</p>
6168
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6169<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6170<p>The type of the incoming values is specified with the first type field. After
6171 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6172 one pair for each predecessor basic block of the current block. Only values
6173 of <a href="#t_firstclass">first class</a> type may be used as the value
6174 arguments to the PHI node. Only labels may be used as the label
6175 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6176
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6177<p>There must be no non-phi instructions between the start of a basic block and
6178 the PHI instructions: i.e. PHI instructions must be first in a basic
6179 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6180
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6181<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6182 occur on the edge from the corresponding predecessor block to the current
6183 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6184 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]6185
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6186<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6187<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6188 specified by the pair corresponding to the predecessor basic block that
6189 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6190
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6191<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6192<pre>
6193Loop: ; Infinite loop that counts from 0 on up...
6194 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6195 %nextindvar = add i32 %indvar, 1
6196 br label %Loop
6197</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6198
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6199</div>
6200
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6201<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6202<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6203 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6204</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6205
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6206<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6207
6208<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6209<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6210 &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>
6211
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6212 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6213</pre>
6214
6215<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6216<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6217 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6218
6219
6220<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6221<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6222 values indicating the condition, and two values of the
6223 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6224 vectors and the condition is a scalar, then entire vectors are selected, not
6225 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6226
6227<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6228<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6229 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6230
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6231<p>If the condition is a vector of i1, then the value arguments must be vectors
6232 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6233
6234<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6235<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6236 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6237</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6238
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6239</div>
6240
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6241<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6242<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6243 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6244</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6245
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6246<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6247
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6248<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6249<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6250 &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]6251</pre>
6252
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6253<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6254<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6255
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6256<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6257<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6258
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6259<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6260 <li>The optional "tail" marker indicates that the callee function does not
6261 access any allocas or varargs in the caller. Note that calls may be
6262 marked "tail" even if they do not occur before
6263 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6264 present, the function call is eligible for tail call optimization,
6265 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6266 optimized into a jump</a>. The code generator may optimize calls marked
6267 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6268 sibling call optimization</a> when the caller and callee have
6269 matching signatures, or 2) forced tail call optimization when the
6270 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6271 <ul>
6272 <li>Caller and callee both have the calling
6273 convention <tt>fastcc</tt>.</li>
6274 <li>The call is in tail position (ret immediately follows call and ret
6275 uses value of call or is void).</li>
6276 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6277 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6278 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6279 constraints are met.</a></li>
6280 </ul>
6281 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6282
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6283 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6284 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6285 defaults to using C calling conventions. The calling convention of the
6286 call must match the calling convention of the target function, or else the
6287 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6288
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6289 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6290 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6291 '<tt>inreg</tt>' attributes are valid here.</li>
6292
6293 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6294 type of the return value. Functions that return no value are marked
6295 <tt><a href="#t_void">void</a></tt>.</li>
6296
6297 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6298 being invoked. The argument types must match the types implied by this
6299 signature. This type can be omitted if the function is not varargs and if
6300 the function type does not return a pointer to a function.</li>
6301
6302 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6303 be invoked. In most cases, this is a direct function invocation, but
6304 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6305 to function value.</li>
6306
6307 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6308 signature argument types and parameter attributes. All arguments must be
6309 of <a href="#t_firstclass">first class</a> type. If the function
6310 signature indicates the function accepts a variable number of arguments,
6311 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312
6313 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6314 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6315 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6316</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6318<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6319<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6320 a specified function, with its incoming arguments bound to the specified
6321 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6322 function, control flow continues with the instruction after the function
6323 call, and the return value of the function is bound to the result
6324 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6326<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6327<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6328 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6329 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6330 %X = tail call i32 @foo() <i>; yields i32</i>
6331 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6332 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6333
6334 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6335 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6336 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6337 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6338 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6339 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6340</pre>
6341
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6342<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6343standard C99 library as being the C99 library functions, and may perform
6344optimizations or generate code for them under that assumption. This is
6345something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6346freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6348</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6349
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6350<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6351<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6352 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6353</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6354
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6355<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6356
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6357<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6358<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6359 &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]6360</pre>
6361
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6362<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6363<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6364 the "variable argument" area of a function call. It is used to implement the
6365 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6366
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6367<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6368<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6369 argument. It returns a value of the specified argument type and increments
6370 the <tt>va_list</tt> to point to the next argument. The actual type
6371 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6372
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6373<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6374<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6375 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6376 to the next argument. For more information, see the variable argument
6377 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6378
6379<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]6380 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6381 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6382
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6383<p><tt>va_arg</tt> is an LLVM instruction instead of
6384 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6385 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6386
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6387<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6388<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6389
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6390<p>Note that the code generator does not yet fully support va_arg on many
6391 targets. Also, it does not currently support va_arg with aggregate types on
6392 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6394</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6395
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6396<!-- _______________________________________________________________________ -->
6397<h4>
6398 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6399</h4>
6400
6401<div>
6402
6403<h5>Syntax:</h5>
6404<pre>
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6405 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6406 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6407
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6408 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6409 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6410</pre>
6411
6412<h5>Overview:</h5>
6413<p>The '<tt>landingpad</tt>' instruction is used by
6414 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6415 system</a> to specify that a basic block is a landing pad &mdash; one where
6416 the exception lands, and corresponds to the code found in the
6417 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6418 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6419 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6420 type <tt>resultty</tt>.</p>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6421
6422<h5>Arguments:</h5>
6423<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6424 function associated with the unwinding mechanism. The optional
6425 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6426
6427<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6428 or <tt>filter</tt> &mdash; and contains the global variable representing the
6429 "type" that may be caught or filtered respectively. Unlike the
6430 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6431 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6432 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6433 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6434
6435<h5>Semantics:</h5>
6436<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6437 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6438 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6439 calling conventions, how the personality function results are represented in
6440 LLVM IR is target specific.</p>
6441
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6442<p>The clauses are applied in order from top to bottom. If two
6443 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6444 clauses from the calling function are appended to the list of clauses.
6445 When the call stack is being unwound due to an exception being thrown, the
6446 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6447 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6448 unwinding continues further up the call stack.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6449
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6450<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6451
6452<ul>
6453 <li>A landing pad block is a basic block which is the unwind destination of an
6454 '<tt>invoke</tt>' instruction.</li>
6455 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6456 first non-PHI instruction.</li>
6457 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6458 pad block.</li>
6459 <li>A basic block that is not a landing pad block may not include a
6460 '<tt>landingpad</tt>' instruction.</li>
6461 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6462 personality function.</li>
6463</ul>
6464
6465<h5>Example:</h5>
6466<pre>
6467 ;; A landing pad which can catch an integer.
6468 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6469 catch i8** @_ZTIi
6470 ;; A landing pad that is a cleanup.
6471 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6472 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6473 ;; A landing pad which can catch an integer and can only throw a double.
6474 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6475 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6476 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6477</pre>
6478
6479</div>
6480
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6481</div>
6482
6483</div>
6484
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6485<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6486<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6487<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6488
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6489<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6490
6491<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6492 well known names and semantics and are required to follow certain
6493 restrictions. Overall, these intrinsics represent an extension mechanism for
6494 the LLVM language that does not require changing all of the transformations
6495 in LLVM when adding to the language (or the bitcode reader/writer, the
6496 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6497
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6498<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6499 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6500 begin with this prefix. Intrinsic functions must always be external
6501 functions: you cannot define the body of intrinsic functions. Intrinsic
6502 functions may only be used in call or invoke instructions: it is illegal to
6503 take the address of an intrinsic function. Additionally, because intrinsic
6504 functions are part of the LLVM language, it is required if any are added that
6505 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6506
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6507<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6508 family of functions that perform the same operation but on different data
6509 types. Because LLVM can represent over 8 million different integer types,
6510 overloading is used commonly to allow an intrinsic function to operate on any
6511 integer type. One or more of the argument types or the result type can be
6512 overloaded to accept any integer type. Argument types may also be defined as
6513 exactly matching a previous argument's type or the result type. This allows
6514 an intrinsic function which accepts multiple arguments, but needs all of them
6515 to be of the same type, to only be overloaded with respect to a single
6516 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6518<p>Overloaded intrinsics will have the names of its overloaded argument types
6519 encoded into its function name, each preceded by a period. Only those types
6520 which are overloaded result in a name suffix. Arguments whose type is matched
6521 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6522 can take an integer of any width and returns an integer of exactly the same
6523 integer width. This leads to a family of functions such as
6524 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6525 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6526 suffix is required. Because the argument's type is matched against the return
6527 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6528
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6529<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6530 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6531
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6532<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6533<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6534 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6535</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6537<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6539<p>Variable argument support is defined in LLVM with
6540 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6541 intrinsic functions. These functions are related to the similarly named
6542 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544<p>All of these functions operate on arguments that use a target-specific value
6545 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6546 not define what this type is, so all transformations should be prepared to
6547 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6548
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6549<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]6550 instruction and the variable argument handling intrinsic functions are
6551 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6552
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6553<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6554define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6555 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6556 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6557 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6558 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6559
6560 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6561 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6562
6563 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6564 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6565 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6566 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6567 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6568
6569 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6570 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6571 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6572}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6573
6574declare void @llvm.va_start(i8*)
6575declare void @llvm.va_copy(i8*, i8*)
6576declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6577</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6578
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6579<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6580<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6581 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6582</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6583
6584
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6585<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6586
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6587<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6588<pre>
6589 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6590</pre>
6591
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6592<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6593<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6594 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]6595
6596<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6597<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]6598
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6599<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6600<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]6601 macro available in C. In a target-dependent way, it initializes
6602 the <tt>va_list</tt> element to which the argument points, so that the next
6603 call to <tt>va_arg</tt> will produce the first variable argument passed to
6604 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6605 need to know the last argument of the function as the compiler can figure
6606 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6607
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6608</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6610<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6611<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6612 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6613</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6614
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6615<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6616
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6617<h5>Syntax:</h5>
6618<pre>
6619 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6620</pre>
6621
6622<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6623<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6624 which has been initialized previously
6625 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6626 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6627
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6628<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6629<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]6630
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6631<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6632<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]6633 macro available in C. In a target-dependent way, it destroys
6634 the <tt>va_list</tt> element to which the argument points. Calls
6635 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6636 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6637 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6639</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6640
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6641<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6642<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6643 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6644</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6645
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6646<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6647
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6648<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6649<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6650 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6651</pre>
6652
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6653<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6654<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6655 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6656
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6657<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6658<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]6659 The second argument is a pointer to a <tt>va_list</tt> element to copy
6660 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6661
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6662<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6663<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]6664 macro available in C. In a target-dependent way, it copies the
6665 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6666 element. This intrinsic is necessary because
6667 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6668 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6669
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6670</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6671
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6672</div>
6673
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6674<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6675<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6676 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6677</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6678
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6679<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6680
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6681<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6682Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6683intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6684roots on the stack</a>, as well as garbage collector implementations that
6685require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6686barriers. Front-ends for type-safe garbage collected languages should generate
6687these intrinsics to make use of the LLVM garbage collectors. For more details,
6688see <a href="GarbageCollection.html">Accurate Garbage Collection with
6689LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6690
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6691<p>The garbage collection intrinsics only operate on objects in the generic
6692 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6693
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6694<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6695<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6696 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6697</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6698
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6699<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6700
6701<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6702<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6703 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6704</pre>
6705
6706<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6707<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]6708 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6709
6710<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6711<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6712 root pointer. The second pointer (which must be either a constant or a
6713 global value address) contains the meta-data to be associated with the
6714 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6715
6716<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6717<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]6718 location. At compile-time, the code generator generates information to allow
6719 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6720 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6721 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6722
6723</div>
6724
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6725<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6726<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6727 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6728</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6729
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6730<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6731
6732<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6733<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6734 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6735</pre>
6736
6737<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6738<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6739 locations, allowing garbage collector implementations that require read
6740 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6741
6742<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6743<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]6744 allocated from the garbage collector. The first object is a pointer to the
6745 start of the referenced object, if needed by the language runtime (otherwise
6746 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6747
6748<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6749<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6750 instruction, but may be replaced with substantially more complex code by the
6751 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6752 may only be used in a function which <a href="#gc">specifies a GC
6753 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6754
6755</div>
6756
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6757<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6758<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6759 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6760</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6762<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6763
6764<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6765<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6766 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6767</pre>
6768
6769<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6770<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6771 locations, allowing garbage collector implementations that require write
6772 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6773
6774<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6775<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]6776 object to store it to, and the third is the address of the field of Obj to
6777 store to. If the runtime does not require a pointer to the object, Obj may
6778 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6779
6780<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6781<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6782 instruction, but may be replaced with substantially more complex code by the
6783 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6784 may only be used in a function which <a href="#gc">specifies a GC
6785 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6786
6787</div>
6788
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6789</div>
6790
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6791<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6792<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6793 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6794</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6795
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6796<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6797
6798<p>These intrinsics are provided by LLVM to expose special features that may
6799 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6800
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6801<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6802<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6803 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6804</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6805
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6806<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6807
6808<h5>Syntax:</h5>
6809<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6810 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6811</pre>
6812
6813<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6814<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6815 target-specific value indicating the return address of the current function
6816 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6817
6818<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6819<p>The argument to this intrinsic indicates which function to return the address
6820 for. Zero indicates the calling function, one indicates its caller, etc.
6821 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6822
6823<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6824<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6825 indicating the return address of the specified call frame, or zero if it
6826 cannot be identified. The value returned by this intrinsic is likely to be
6827 incorrect or 0 for arguments other than zero, so it should only be used for
6828 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6830<p>Note that calling this intrinsic does not prevent function inlining or other
6831 aggressive transformations, so the value returned may not be that of the
6832 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6833
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6834</div>
6835
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6836<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6837<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6838 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6839</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6840
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6841<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6842
6843<h5>Syntax:</h5>
6844<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6845 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6846</pre>
6847
6848<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6849<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6850 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6851
6852<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6853<p>The argument to this intrinsic indicates which function to return the frame
6854 pointer for. Zero indicates the calling function, one indicates its caller,
6855 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6856
6857<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6858<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6859 indicating the frame address of the specified call frame, or zero if it
6860 cannot be identified. The value returned by this intrinsic is likely to be
6861 incorrect or 0 for arguments other than zero, so it should only be used for
6862 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6864<p>Note that calling this intrinsic does not prevent function inlining or other
6865 aggressive transformations, so the value returned may not be that of the
6866 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6867
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6868</div>
6869
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6870<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6871<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6872 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6873</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6875<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6876
6877<h5>Syntax:</h5>
6878<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6879 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6880</pre>
6881
6882<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6883<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6884 of the function stack, for use
6885 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6886 useful for implementing language features like scoped automatic variable
6887 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6888
6889<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6890<p>This intrinsic returns a opaque pointer value that can be passed
6891 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6892 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6893 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6894 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6895 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6896 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6897
6898</div>
6899
6900<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6901<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6902 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6903</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6904
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6905<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6906
6907<h5>Syntax:</h5>
6908<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6909 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6910</pre>
6911
6912<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6913<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6914 the function stack to the state it was in when the
6915 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6916 executed. This is useful for implementing language features like scoped
6917 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6918
6919<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920<p>See the description
6921 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6922
6923</div>
6924
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6925<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6926<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6927 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6928</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6929
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6930<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6931
6932<h5>Syntax:</h5>
6933<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6934 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]6935</pre>
6936
6937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6939 insert a prefetch instruction if supported; otherwise, it is a noop.
6940 Prefetches have no effect on the behavior of the program but can change its
6941 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6942
6943<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6944<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6945 specifier determining if the fetch should be for a read (0) or write (1),
6946 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6947 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6948 specifies whether the prefetch is performed on the data (1) or instruction (0)
6949 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6950 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6951
6952<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953<p>This intrinsic does not modify the behavior of the program. In particular,
6954 prefetches cannot trap and do not produce a value. On targets that support
6955 this intrinsic, the prefetch can provide hints to the processor cache for
6956 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6957
6958</div>
6959
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6960<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6961<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6962 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6963</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6964
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6965<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6966
6967<h5>Syntax:</h5>
6968<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6969 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6970</pre>
6971
6972<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6973<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6974 Counter (PC) in a region of code to simulators and other tools. The method
6975 is target specific, but it is expected that the marker will use exported
6976 symbols to transmit the PC of the marker. The marker makes no guarantees
6977 that it will remain with any specific instruction after optimizations. It is
6978 possible that the presence of a marker will inhibit optimizations. The
6979 intended use is to be inserted after optimizations to allow correlations of
6980 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6981
6982<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6984
6985<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6987 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6988
6989</div>
6990
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6991<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6992<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6993 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6994</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6995
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6996<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6997
6998<h5>Syntax:</h5>
6999<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7000 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +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.readcyclecounter</tt>' intrinsic provides access to the cycle
7005 counter register (or similar low latency, high accuracy clocks) on those
7006 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7007 should map to RPCC. As the backing counters overflow quickly (on the order
7008 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7009
7010<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011<p>When directly supported, reading the cycle counter should not modify any
7012 memory. Implementations are allowed to either return a application specific
7013 value or a system wide value. On backends without support, this is lowered
7014 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7015
7016</div>
7017
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7018</div>
7019
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7020<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7021<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7022 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7023</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7024
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7025<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7026
7027<p>LLVM provides intrinsics for a few important standard C library functions.
7028 These intrinsics allow source-language front-ends to pass information about
7029 the alignment of the pointer arguments to the code generator, providing
7030 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7031
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7032<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7033<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7034 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7035</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7036
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7037<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7038
7039<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040<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]7041 integer bit width and for different address spaces. Not all targets support
7042 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7043
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7044<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7045 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]7046 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7047 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]7048 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7049</pre>
7050
7051<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7053 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7055<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7056 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7057 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7058
7059<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7060
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7061<p>The first argument is a pointer to the destination, the second is a pointer
7062 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7063 number of bytes to copy, the fourth argument is the alignment of the
7064 source and destination locations, and the fifth is a boolean indicating a
7065 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7066
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7067<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]7068 then the caller guarantees that both the source and destination pointers are
7069 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7070
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7071<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7072 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7073 The detailed access behavior is not very cleanly specified and it is unwise
7074 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7075
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7076<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7078<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7079 source location to the destination location, which are not allowed to
7080 overlap. It copies "len" bytes of memory over. If the argument is known to
7081 be aligned to some boundary, this can be specified as the fourth argument,
7082 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7083
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7084</div>
7085
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7086<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7087<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7088 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7089</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7090
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7091<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7092
7093<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7094<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]7095 width and for different address space. Not all targets support all bit
7096 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7098<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7099 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]7100 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7101 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]7102 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7103</pre>
7104
7105<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7106<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7107 source location to the destination location. It is similar to the
7108 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7109 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7110
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7111<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7112 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7113 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7114
7115<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7117<p>The first argument is a pointer to the destination, the second is a pointer
7118 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7119 number of bytes to copy, the fourth argument is the alignment of the
7120 source and destination locations, and the fifth is a boolean indicating a
7121 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7122
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7123<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]7124 then the caller guarantees that the source and destination pointers are
7125 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7126
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7127<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7128 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7129 The detailed access behavior is not very cleanly specified and it is unwise
7130 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7131
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7132<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7135 source location to the destination location, which may overlap. It copies
7136 "len" bytes of memory over. If the argument is known to be aligned to some
7137 boundary, this can be specified as the fourth argument, otherwise it should
7138 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7139
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7140</div>
7141
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7142<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7143<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7144 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7145</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7146
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7147<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7148
7149<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7150<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]7151 width and for different address spaces. However, not all targets support all
7152 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7153
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7154<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7155 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7156 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7157 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7158 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7159</pre>
7160
7161<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7162<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7163 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7164
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7165<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7166 intrinsic does not return a value and takes extra alignment/volatile
7167 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7168
7169<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7170<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]7171 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7172 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7173 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7174
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7175<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]7176 then the caller guarantees that the destination pointer is aligned to that
7177 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7178
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7179<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7180 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7181 The detailed access behavior is not very cleanly specified and it is unwise
7182 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7183
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7184<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7185<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7186 at the destination location. If the argument is known to be aligned to some
7187 boundary, this can be specified as the fourth argument, otherwise it should
7188 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7189
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7190</div>
7191
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7192<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7193<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7194 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7195</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7196
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7197<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7198
7199<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7200<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7201 floating point or vector of floating point type. Not all targets support all
7202 types however.</p>
7203
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7204<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7205 declare float @llvm.sqrt.f32(float %Val)
7206 declare double @llvm.sqrt.f64(double %Val)
7207 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7208 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7209 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7210</pre>
7211
7212<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7213<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7214 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7215 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7216 behavior for negative numbers other than -0.0 (which allows for better
7217 optimization, because there is no need to worry about errno being
7218 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]7219
7220<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221<p>The argument and return value are floating point numbers of the same
7222 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7223
7224<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7225<p>This function returns the sqrt of the specified operand if it is a
7226 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7227
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7228</div>
7229
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7230<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7231<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7232 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7233</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7234
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7235<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7236
7237<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7238<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7239 floating point or vector of floating point type. Not all targets support all
7240 types however.</p>
7241
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7242<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7243 declare float @llvm.powi.f32(float %Val, i32 %power)
7244 declare double @llvm.powi.f64(double %Val, i32 %power)
7245 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7246 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7247 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7248</pre>
7249
7250<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7251<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7252 specified (positive or negative) power. The order of evaluation of
7253 multiplications is not defined. When a vector of floating point type is
7254 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7255
7256<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7257<p>The second argument is an integer power, and the first is a value to raise to
7258 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7259
7260<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7261<p>This function returns the first value raised to the second power with an
7262 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7263
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7264</div>
7265
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7266<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7267<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7268 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7269</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7270
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7271<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7272
7273<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7274<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7275 floating point or vector of floating point type. Not all targets support all
7276 types however.</p>
7277
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7278<pre>
7279 declare float @llvm.sin.f32(float %Val)
7280 declare double @llvm.sin.f64(double %Val)
7281 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7282 declare fp128 @llvm.sin.f128(fp128 %Val)
7283 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7284</pre>
7285
7286<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7287<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7288
7289<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7290<p>The argument and return value are floating point numbers of the same
7291 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7292
7293<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7294<p>This function returns the sine of the specified operand, returning the same
7295 values as the libm <tt>sin</tt> functions would, and handles error conditions
7296 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7297
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7298</div>
7299
7300<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7301<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7302 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7303</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7304
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7305<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7306
7307<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7308<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7309 floating point or vector of floating point type. Not all targets support all
7310 types however.</p>
7311
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7312<pre>
7313 declare float @llvm.cos.f32(float %Val)
7314 declare double @llvm.cos.f64(double %Val)
7315 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7316 declare fp128 @llvm.cos.f128(fp128 %Val)
7317 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7318</pre>
7319
7320<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7321<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7322
7323<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7324<p>The argument and return value are floating point numbers of the same
7325 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7326
7327<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7328<p>This function returns the cosine of the specified operand, returning the same
7329 values as the libm <tt>cos</tt> functions would, and handles error conditions
7330 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7331
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7332</div>
7333
7334<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7335<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7336 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7337</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7338
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7339<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7340
7341<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7342<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7343 floating point or vector of floating point type. Not all targets support all
7344 types however.</p>
7345
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7346<pre>
7347 declare float @llvm.pow.f32(float %Val, float %Power)
7348 declare double @llvm.pow.f64(double %Val, double %Power)
7349 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7350 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7351 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7352</pre>
7353
7354<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7355<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7356 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7357
7358<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7359<p>The second argument is a floating point power, and the first is a value to
7360 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7361
7362<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7363<p>This function returns the first value raised to the second power, returning
7364 the same values as the libm <tt>pow</tt> functions would, and handles error
7365 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7366
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7367</div>
7368
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7369<!-- _______________________________________________________________________ -->
7370<h4>
7371 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7372</h4>
7373
7374<div>
7375
7376<h5>Syntax:</h5>
7377<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7378 floating point or vector of floating point type. Not all targets support all
7379 types however.</p>
7380
7381<pre>
7382 declare float @llvm.exp.f32(float %Val)
7383 declare double @llvm.exp.f64(double %Val)
7384 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7385 declare fp128 @llvm.exp.f128(fp128 %Val)
7386 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7387</pre>
7388
7389<h5>Overview:</h5>
7390<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7391
7392<h5>Arguments:</h5>
7393<p>The argument and return value are floating point numbers of the same
7394 type.</p>
7395
7396<h5>Semantics:</h5>
7397<p>This function returns the same values as the libm <tt>exp</tt> functions
7398 would, and handles error conditions in the same way.</p>
7399
7400</div>
7401
7402<!-- _______________________________________________________________________ -->
7403<h4>
7404 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7405</h4>
7406
7407<div>
7408
7409<h5>Syntax:</h5>
7410<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7411 floating point or vector of floating point type. Not all targets support all
7412 types however.</p>
7413
7414<pre>
7415 declare float @llvm.log.f32(float %Val)
7416 declare double @llvm.log.f64(double %Val)
7417 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7418 declare fp128 @llvm.log.f128(fp128 %Val)
7419 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7420</pre>
7421
7422<h5>Overview:</h5>
7423<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7424
7425<h5>Arguments:</h5>
7426<p>The argument and return value are floating point numbers of the same
7427 type.</p>
7428
7429<h5>Semantics:</h5>
7430<p>This function returns the same values as the libm <tt>log</tt> functions
7431 would, and handles error conditions in the same way.</p>
7432
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7433</div>
7434
7435<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7436<h4>
7437 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7438</h4>
7439
7440<div>
7441
7442<h5>Syntax:</h5>
7443<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7444 floating point or vector of floating point type. Not all targets support all
7445 types however.</p>
7446
7447<pre>
7448 declare float @llvm.fma.f32(float %a, float %b, float %c)
7449 declare double @llvm.fma.f64(double %a, double %b, double %c)
7450 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7451 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7452 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7453</pre>
7454
7455<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7456<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7457 operation.</p>
7458
7459<h5>Arguments:</h5>
7460<p>The argument and return value are floating point numbers of the same
7461 type.</p>
7462
7463<h5>Semantics:</h5>
7464<p>This function returns the same values as the libm <tt>fma</tt> functions
7465 would.</p>
7466
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7467</div>
7468
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7469</div>
7470
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7471<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7472<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7473 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7474</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7475
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7476<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7477
7478<p>LLVM provides intrinsics for a few important bit manipulation operations.
7479 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7480
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7481<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7482<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7483 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7484</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7486<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7487
7488<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7489<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7490 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7491
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7492<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7493 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7494 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7495 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7496</pre>
7497
7498<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7499<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7500 values with an even number of bytes (positive multiple of 16 bits). These
7501 are useful for performing operations on data that is not in the target's
7502 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7503
7504<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7505<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7506 and low byte of the input i16 swapped. Similarly,
7507 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7508 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7509 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7510 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7511 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7512 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7513
7514</div>
7515
7516<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7517<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7518 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7519</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7520
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7521<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7522
7523<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7524<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]7525 width, or on any vector with integer elements. Not all targets support all
7526 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7527
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7528<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7529 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7530 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7531 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7532 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7533 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7534 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]7535</pre>
7536
7537<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7538<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7539 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7540
7541<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7542<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]7543 integer type, or a vector with integer elements.
7544 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7545
7546<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7547<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7548 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7549
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7550</div>
7551
7552<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7553<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7554 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7555</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7556
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7557<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7558
7559<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7560<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]7561 integer bit width, or any vector whose elements are integers. Not all
7562 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7563
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7564<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7565 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7566 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7567 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7568 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7569 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7570 declase &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7571</pre>
7572
7573<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7574<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7575 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7576
7577<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7578<p>The first argument is the value to be counted. This argument may be of any
7579 integer type, or a vectory with integer element type. The return type
7580 must match the first argument type.</p>
7581
7582<p>The second argument must be a constant and is a flag to indicate whether the
7583 intrinsic should ensure that a zero as the first argument produces a defined
7584 result. Historically some architectures did not provide a defined result for
7585 zero values as efficiently, and many algorithms are now predicated on
7586 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7587
7588<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7589<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7590 zeros in a variable, or within each element of the vector.
7591 If <tt>src == 0</tt> then the result is the size in bits of the type of
7592 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7593 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7594
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7595</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7596
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7597<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7598<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7599 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7600</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7601
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7602<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7603
7604<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7605<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]7606 integer bit width, or any vector of integer elements. Not all targets
7607 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7608
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7609<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7610 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7611 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7612 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7613 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7614 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7615 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7616</pre>
7617
7618<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7619<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7620 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7621
7622<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7623<p>The first argument is the value to be counted. This argument may be of any
7624 integer type, or a vectory with integer element type. The return type
7625 must match the first argument type.</p>
7626
7627<p>The second argument must be a constant and is a flag to indicate whether the
7628 intrinsic should ensure that a zero as the first argument produces a defined
7629 result. Historically some architectures did not provide a defined result for
7630 zero values as efficiently, and many algorithms are now predicated on
7631 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7632
7633<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7634<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7635 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7636 If <tt>src == 0</tt> then the result is the size in bits of the type of
7637 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7638 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7639
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7640</div>
7641
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7642</div>
7643
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7644<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7645<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7646 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7647</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7648
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7649<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7650
7651<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7652
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7653<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7654<h4>
7655 <a name="int_sadd_overflow">
7656 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7657 </a>
7658</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7659
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7660<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7661
7662<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7663<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]7664 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7665
7666<pre>
7667 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7668 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7669 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7670</pre>
7671
7672<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7673<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674 a signed addition of the two arguments, and indicate whether an overflow
7675 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7676
7677<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7678<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]7679 be of integer types of any bit width, but they must have the same bit
7680 width. The second element of the result structure must be of
7681 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7682 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7683
7684<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7685<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7686 a signed addition of the two variables. They return a structure &mdash; the
7687 first element of which is the signed summation, and the second element of
7688 which is a bit specifying if the signed summation resulted in an
7689 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7690
7691<h5>Examples:</h5>
7692<pre>
7693 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7694 %sum = extractvalue {i32, i1} %res, 0
7695 %obit = extractvalue {i32, i1} %res, 1
7696 br i1 %obit, label %overflow, label %normal
7697</pre>
7698
7699</div>
7700
7701<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7702<h4>
7703 <a name="int_uadd_overflow">
7704 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7705 </a>
7706</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7707
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7708<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7709
7710<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7711<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]7712 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7713
7714<pre>
7715 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7716 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7717 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7718</pre>
7719
7720<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7721<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7722 an unsigned addition of the two arguments, and indicate whether a carry
7723 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7724
7725<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7726<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]7727 be of integer types of any bit width, but they must have the same bit
7728 width. The second element of the result structure must be of
7729 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7730 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7731
7732<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7733<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7734 an unsigned addition of the two arguments. They return a structure &mdash;
7735 the first element of which is the sum, and the second element of which is a
7736 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7737
7738<h5>Examples:</h5>
7739<pre>
7740 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7741 %sum = extractvalue {i32, i1} %res, 0
7742 %obit = extractvalue {i32, i1} %res, 1
7743 br i1 %obit, label %carry, label %normal
7744</pre>
7745
7746</div>
7747
7748<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7749<h4>
7750 <a name="int_ssub_overflow">
7751 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7752 </a>
7753</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7754
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7755<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7756
7757<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7758<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]7759 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7760
7761<pre>
7762 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7763 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7764 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7765</pre>
7766
7767<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7768<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7769 a signed subtraction of the two arguments, and indicate whether an overflow
7770 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7771
7772<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7773<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]7774 be of integer types of any bit width, but they must have the same bit
7775 width. The second element of the result structure must be of
7776 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7777 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7778
7779<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7780<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7781 a signed subtraction of the two arguments. They return a structure &mdash;
7782 the first element of which is the subtraction, and the second element of
7783 which is a bit specifying if the signed subtraction resulted in an
7784 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7785
7786<h5>Examples:</h5>
7787<pre>
7788 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7789 %sum = extractvalue {i32, i1} %res, 0
7790 %obit = extractvalue {i32, i1} %res, 1
7791 br i1 %obit, label %overflow, label %normal
7792</pre>
7793
7794</div>
7795
7796<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7797<h4>
7798 <a name="int_usub_overflow">
7799 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7800 </a>
7801</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7803<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7804
7805<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7806<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]7807 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7808
7809<pre>
7810 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7811 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7812 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7813</pre>
7814
7815<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7816<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7817 an unsigned subtraction of the two arguments, and indicate whether an
7818 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7819
7820<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7821<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]7822 be of integer types of any bit width, but they must have the same bit
7823 width. The second element of the result structure must be of
7824 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7825 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7826
7827<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7828<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7829 an unsigned subtraction of the two arguments. They return a structure &mdash;
7830 the first element of which is the subtraction, and the second element of
7831 which is a bit specifying if the unsigned subtraction resulted in an
7832 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7833
7834<h5>Examples:</h5>
7835<pre>
7836 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7837 %sum = extractvalue {i32, i1} %res, 0
7838 %obit = extractvalue {i32, i1} %res, 1
7839 br i1 %obit, label %overflow, label %normal
7840</pre>
7841
7842</div>
7843
7844<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7845<h4>
7846 <a name="int_smul_overflow">
7847 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7848 </a>
7849</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7850
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7851<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7852
7853<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7854<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]7855 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7856
7857<pre>
7858 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7859 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7860 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7861</pre>
7862
7863<h5>Overview:</h5>
7864
7865<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7866 a signed multiplication of the two arguments, and indicate whether an
7867 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7868
7869<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7870<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]7871 be of integer types of any bit width, but they must have the same bit
7872 width. The second element of the result structure must be of
7873 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7874 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7875
7876<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7877<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7878 a signed multiplication of the two arguments. They return a structure &mdash;
7879 the first element of which is the multiplication, and the second element of
7880 which is a bit specifying if the signed multiplication resulted in an
7881 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7882
7883<h5>Examples:</h5>
7884<pre>
7885 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7886 %sum = extractvalue {i32, i1} %res, 0
7887 %obit = extractvalue {i32, i1} %res, 1
7888 br i1 %obit, label %overflow, label %normal
7889</pre>
7890
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7891</div>
7892
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7893<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7894<h4>
7895 <a name="int_umul_overflow">
7896 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7897 </a>
7898</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7899
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7900<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7901
7902<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7903<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]7904 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7905
7906<pre>
7907 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7908 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7909 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7910</pre>
7911
7912<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7913<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7914 a unsigned multiplication of the two arguments, and indicate whether an
7915 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7916
7917<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7918<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]7919 be of integer types of any bit width, but they must have the same bit
7920 width. The second element of the result structure must be of
7921 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7922 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7923
7924<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7925<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7926 an unsigned multiplication of the two arguments. They return a structure
7927 &mdash; the first element of which is the multiplication, and the second
7928 element of which is a bit specifying if the unsigned multiplication resulted
7929 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7930
7931<h5>Examples:</h5>
7932<pre>
7933 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7934 %sum = extractvalue {i32, i1} %res, 0
7935 %obit = extractvalue {i32, i1} %res, 1
7936 br i1 %obit, label %overflow, label %normal
7937</pre>
7938
7939</div>
7940
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7941</div>
7942
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7943<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7944<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7945 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7946</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7947
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7948<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7949
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7950<p>Half precision floating point is a storage-only format. This means that it is
7951 a dense encoding (in memory) but does not support computation in the
7952 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7953
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7954<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7955 value as an i16, then convert it to float with <a
7956 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7957 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7958 double etc). To store the value back to memory, it is first converted to
7959 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7960 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7961 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7962
7963<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7964<h4>
7965 <a name="int_convert_to_fp16">
7966 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7967 </a>
7968</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7969
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7970<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7971
7972<h5>Syntax:</h5>
7973<pre>
7974 declare i16 @llvm.convert.to.fp16(f32 %a)
7975</pre>
7976
7977<h5>Overview:</h5>
7978<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7979 a conversion from single precision floating point format to half precision
7980 floating point format.</p>
7981
7982<h5>Arguments:</h5>
7983<p>The intrinsic function contains single argument - the value to be
7984 converted.</p>
7985
7986<h5>Semantics:</h5>
7987<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7988 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7989 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7990 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7991
7992<h5>Examples:</h5>
7993<pre>
7994 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7995 store i16 %res, i16* @x, align 2
7996</pre>
7997
7998</div>
7999
8000<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8001<h4>
8002 <a name="int_convert_from_fp16">
8003 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8004 </a>
8005</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8006
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8007<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8008
8009<h5>Syntax:</h5>
8010<pre>
8011 declare f32 @llvm.convert.from.fp16(i16 %a)
8012</pre>
8013
8014<h5>Overview:</h5>
8015<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8016 a conversion from half precision floating point format to single precision
8017 floating point format.</p>
8018
8019<h5>Arguments:</h5>
8020<p>The intrinsic function contains single argument - the value to be
8021 converted.</p>
8022
8023<h5>Semantics:</h5>
8024<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8025 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8026 precision floating point format. The input half-float value is represented by
8027 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8028
8029<h5>Examples:</h5>
8030<pre>
8031 %a = load i16* @x, align 2
8032 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8033</pre>
8034
8035</div>
8036
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8037</div>
8038
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8039<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8040<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8041 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8042</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8043
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8044<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8045
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8046<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8047 prefix), are described in
8048 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8049 Level Debugging</a> document.</p>
8050
8051</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8052
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8053<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8054<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8055 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8056</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8057
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8058<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8059
8060<p>The LLVM exception handling intrinsics (which all start with
8061 <tt>llvm.eh.</tt> prefix), are described in
8062 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8063 Handling</a> document.</p>
8064
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8065</div>
8066
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8067<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8068<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8069 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8070</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8071
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8072<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8073
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8074<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]8075 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8076 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8077 function pointer lacking the nest parameter - the caller does not need to
8078 provide a value for it. Instead, the value to use is stored in advance in a
8079 "trampoline", a block of memory usually allocated on the stack, which also
8080 contains code to splice the nest value into the argument list. This is used
8081 to implement the GCC nested function address extension.</p>
8082
8083<p>For example, if the function is
8084 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8085 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8086 follows:</p>
8087
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]8088<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8089 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8090 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8091 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8092 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8093 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8094</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8095
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8096<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8097 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8098
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8099<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8100<h4>
8101 <a name="int_it">
8102 '<tt>llvm.init.trampoline</tt>' Intrinsic
8103 </a>
8104</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8106<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8107
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8108<h5>Syntax:</h5>
8109<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8110 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]8111</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8112
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8113<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8114<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8115 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8116
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8117<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8118<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8119 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8120 sufficiently aligned block of memory; this memory is written to by the
8121 intrinsic. Note that the size and the alignment are target-specific - LLVM
8122 currently provides no portable way of determining them, so a front-end that
8123 generates this intrinsic needs to have some target-specific knowledge.
8124 The <tt>func</tt> argument must hold a function bitcast to
8125 an <tt>i8*</tt>.</p>
8126
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8127<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8128<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]8129 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8130 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8131 which can be <a href="#int_trampoline">bitcast (to a new function) and
8132 called</a>. The new function's signature is the same as that of
8133 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8134 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8135 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8136 with the same argument list, but with <tt>nval</tt> used for the missing
8137 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8138 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8139 to the returned function pointer is undefined.</p>
8140</div>
8141
8142<!-- _______________________________________________________________________ -->
8143<h4>
8144 <a name="int_at">
8145 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8146 </a>
8147</h4>
8148
8149<div>
8150
8151<h5>Syntax:</h5>
8152<pre>
8153 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8154</pre>
8155
8156<h5>Overview:</h5>
8157<p>This performs any required machine-specific adjustment to the address of a
8158 trampoline (passed as <tt>tramp</tt>).</p>
8159
8160<h5>Arguments:</h5>
8161<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8162 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8163 </a>.</p>
8164
8165<h5>Semantics:</h5>
8166<p>On some architectures the address of the code to be executed needs to be
8167 different to the address where the trampoline is actually stored. This
8168 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8169 after performing the required machine specific adjustments.
8170 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8171 executed</a>.
8172</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8173
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8174</div>
8175
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8176</div>
8177
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8178<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8179<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8180 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8181</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8182
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8183<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8184
8185<p>This class of intrinsics exists to information about the lifetime of memory
8186 objects and ranges where variables are immutable.</p>
8187
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8188<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8189<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8190 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8191</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8192
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8193<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8194
8195<h5>Syntax:</h5>
8196<pre>
8197 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8198</pre>
8199
8200<h5>Overview:</h5>
8201<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8202 object's lifetime.</p>
8203
8204<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8205<p>The first argument is a constant integer representing the size of the
8206 object, or -1 if it is variable sized. The second argument is a pointer to
8207 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8208
8209<h5>Semantics:</h5>
8210<p>This intrinsic indicates that before this point in the code, the value of the
8211 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]8212 never be used and has an undefined value. A load from the pointer that
8213 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8214 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8215
8216</div>
8217
8218<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8219<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8220 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8221</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8222
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8223<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8224
8225<h5>Syntax:</h5>
8226<pre>
8227 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8228</pre>
8229
8230<h5>Overview:</h5>
8231<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8232 object's lifetime.</p>
8233
8234<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8235<p>The first argument is a constant integer representing the size of the
8236 object, or -1 if it is variable sized. The second argument is a pointer to
8237 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8238
8239<h5>Semantics:</h5>
8240<p>This intrinsic indicates that after this point in the code, the value of the
8241 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8242 never be used and has an undefined value. Any stores into the memory object
8243 following this intrinsic may be removed as dead.
8244
8245</div>
8246
8247<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8248<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8249 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8250</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8251
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8252<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8253
8254<h5>Syntax:</h5>
8255<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8256 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8257</pre>
8258
8259<h5>Overview:</h5>
8260<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8261 a memory object will not change.</p>
8262
8263<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8264<p>The first argument is a constant integer representing the size of the
8265 object, or -1 if it is variable sized. The second argument is a pointer to
8266 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8267
8268<h5>Semantics:</h5>
8269<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8270 the return value, the referenced memory location is constant and
8271 unchanging.</p>
8272
8273</div>
8274
8275<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8276<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8277 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8278</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8280<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8281
8282<h5>Syntax:</h5>
8283<pre>
8284 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8285</pre>
8286
8287<h5>Overview:</h5>
8288<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8289 a memory object are mutable.</p>
8290
8291<h5>Arguments:</h5>
8292<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8293 The second argument is a constant integer representing the size of the
8294 object, or -1 if it is variable sized and the third argument is a pointer
8295 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8296
8297<h5>Semantics:</h5>
8298<p>This intrinsic indicates that the memory is mutable again.</p>
8299
8300</div>
8301
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8302</div>
8303
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8304<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8305<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8306 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8307</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8308
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8309<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8310
8311<p>This class of intrinsics is designed to be generic and has no specific
8312 purpose.</p>
8313
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8314<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8315<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8316 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8317</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8318
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8319<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8320
8321<h5>Syntax:</h5>
8322<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8323 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]8324</pre>
8325
8326<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8327<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8328
8329<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8330<p>The first argument is a pointer to a value, the second is a pointer to a
8331 global string, the third is a pointer to a global string which is the source
8332 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8333
8334<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8335<p>This intrinsic allows annotation of local variables with arbitrary strings.
8336 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8337 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8338 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8339
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8340</div>
8341
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8342<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8343<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8344 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8345</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8346
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8347<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8348
8349<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8350<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8351 any integer bit width.</p>
8352
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8353<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8354 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8355 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8356 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8357 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8358 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]8359</pre>
8360
8361<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8362<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8363
8364<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8365<p>The first argument is an integer value (result of some expression), the
8366 second is a pointer to a global string, the third is a pointer to a global
8367 string which is the source file name, and the last argument is the line
8368 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8369
8370<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8371<p>This intrinsic allows annotations to be put on arbitrary expressions with
8372 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8373 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8374 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8375
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8376</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8377
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8378<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8379<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8380 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8381</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8382
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8383<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8384
8385<h5>Syntax:</h5>
8386<pre>
8387 declare void @llvm.trap()
8388</pre>
8389
8390<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8391<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8392
8393<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8394<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8395
8396<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8397<p>This intrinsics is lowered to the target dependent trap instruction. If the
8398 target does not have a trap instruction, this intrinsic will be lowered to
8399 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8400
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8401</div>
8402
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8403<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8404<h4>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame^]8405 <a name="int_debugger">'<tt>llvm.debugger</tt>' Intrinsic</a>
8406</h4>
8407
8408<div>
8409
8410<h5>Syntax:</h5>
8411<pre>
8412 declare void @llvm.debugger()
8413</pre>
8414
8415<h5>Overview:</h5>
8416<p>The '<tt>llvm.debugger</tt>' intrinsic.</p>
8417
8418<h5>Arguments:</h5>
8419<p>None.</p>
8420
8421<h5>Semantics:</h5>
8422<p>This intrinsic is lowered to code which is intended to cause an execution
8423 trap with the intention of requesting the attention of a debugger.</p>
8424
8425</div>
8426
8427<!-- _______________________________________________________________________ -->
8428<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8429 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8430</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8431
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8432<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8433
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8434<h5>Syntax:</h5>
8435<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8436 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8437</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8438
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8439<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8440<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8441 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8442 ensure that it is placed on the stack before local variables.</p>
8443
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8444<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8445<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8446 arguments. The first argument is the value loaded from the stack
8447 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8448 that has enough space to hold the value of the guard.</p>
8449
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8450<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8451<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8452 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8453 stack. This is to ensure that if a local variable on the stack is
8454 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8455 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8456 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8457 function.</p>
8458
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8459</div>
8460
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8461<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8462<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8463 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8464</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8465
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8466<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8467
8468<h5>Syntax:</h5>
8469<pre>
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8470 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;, i32 &lt;runtime&gt;)
8471 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;, i32 &lt;runtime&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8472</pre>
8473
8474<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8475<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8476 the optimizers to determine at compile time whether a) an operation (like
8477 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8478 runtime check for overflow isn't necessary. An object in this context means
8479 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8480
8481<h5>Arguments:</h5>
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8482<p>The <tt>llvm.objectsize</tt> intrinsic takes three arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8483 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8484 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if true)
8485 or -1 (if false) when the object size is unknown.
8486 The third argument, <tt>runtime</tt>, indicates whether the compiler is allowed
8487 to return a non-constant value. The higher the value, the higher the potential
8488 run-time performance impact.
8489 The second and third arguments only accepts constants.</p>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8490
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8491<h5>Semantics:</h5>
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8492<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8493 the size of the object concerned. If the size cannot be determined at compile
8494 time, <tt>llvm.objectsize</tt> either returns <tt>i32/i64 -1 or 0</tt>
8495 (depending on the <tt>min</tt> argument) if <tt>runtime</tt> is 0, or a run-time
8496 value (if <tt>runtime</tt> &gt; 0 and an expression could be generated).</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8497
8498</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8499<!-- _______________________________________________________________________ -->
8500<h4>
8501 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8502</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8503
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8504<div>
8505
8506<h5>Syntax:</h5>
8507<pre>
8508 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8509 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8510</pre>
8511
8512<h5>Overview:</h5>
8513<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8514 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8515
8516<h5>Arguments:</h5>
8517<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8518 argument is a value. The second argument is an expected value, this needs to
8519 be a constant value, variables are not allowed.</p>
8520
8521<h5>Semantics:</h5>
8522<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8523</div>
8524
8525</div>
8526
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8527</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8528<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8529<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8530<address>
8531 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8532 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8533 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8534 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]8535
8536 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8537 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8538 Last modified: $Date$
8539</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8540
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8541</body>
8542</html>