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gerrit-public.fairphone.software / platform / external / llvm / 95c88b8cb210ffad127519a143fade685ab21f5b / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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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>
Peter Collingbourne168a4c32012-07-03 12:25:40 +0000[diff] [blame]260 <li><a href="#int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]261 </ol>
262 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]263 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]264 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]265 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]266 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
267 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
268 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]269 </ol>
270 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]271 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
272 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]273 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
274 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
275 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
276 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
277 <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]278 <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]279 </ol>
280 </li>
Lang Hames5afba6f2012-06-05 19:07:46 +0000[diff] [blame]281 <li><a href="#spec_arithmetic">Specialised Arithmetic Intrinsics</a>
282 <ol>
283 <li><a href="#fmuladd">'<tt>llvm.fmuladd</tt> Intrinsic</a></li>
284 </ol>
285 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]286 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
287 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]288 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
289 <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]290 </ol>
291 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]292 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]293 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]294 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]295 <ol>
296 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]297 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]298 </ol>
299 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]300 <li><a href="#int_memorymarkers">Memory Use Markers</a>
301 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]302 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
303 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
304 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
305 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]306 </ol>
307 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]308 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]309 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]310 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]311 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]312 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]313 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]314 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]315 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]316 <li><a href="#int_debugtrap">
317 '<tt>llvm.debugtrap</tt>' Intrinsic</a></li>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]318 <li><a href="#int_stackprotector">
319 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]320 <li><a href="#int_objectsize">
321 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]322 <li><a href="#int_expect">
323 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]324 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]325 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]326 </ol>
327 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]328</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]329
330<div class="doc_author">
331 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
332 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]336<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]339<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]340
341<p>This document is a reference manual for the LLVM assembly language. LLVM is
342 a Static Single Assignment (SSA) based representation that provides type
343 safety, low-level operations, flexibility, and the capability of representing
344 'all' high-level languages cleanly. It is the common code representation
345 used throughout all phases of the LLVM compilation strategy.</p>
346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]347</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]349<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]350<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]351<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]352
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]353<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]354
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]355<p>The LLVM code representation is designed to be used in three different forms:
356 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
357 for fast loading by a Just-In-Time compiler), and as a human readable
358 assembly language representation. This allows LLVM to provide a powerful
359 intermediate representation for efficient compiler transformations and
360 analysis, while providing a natural means to debug and visualize the
361 transformations. The three different forms of LLVM are all equivalent. This
362 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]364<p>The LLVM representation aims to be light-weight and low-level while being
365 expressive, typed, and extensible at the same time. It aims to be a
366 "universal IR" of sorts, by being at a low enough level that high-level ideas
367 may be cleanly mapped to it (similar to how microprocessors are "universal
368 IR's", allowing many source languages to be mapped to them). By providing
369 type information, LLVM can be used as the target of optimizations: for
370 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]371 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]372 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]374<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]375<h4>
376 <a name="wellformed">Well-Formedness</a>
377</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]379<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]380
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]381<p>It is important to note that this document describes 'well formed' LLVM
382 assembly language. There is a difference between what the parser accepts and
383 what is considered 'well formed'. For example, the following instruction is
384 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]385
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]386<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]387%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388</pre>
389
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]390<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
391 LLVM infrastructure provides a verification pass that may be used to verify
392 that an LLVM module is well formed. This pass is automatically run by the
393 parser after parsing input assembly and by the optimizer before it outputs
394 bitcode. The violations pointed out by the verifier pass indicate bugs in
395 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]397</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]398
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]399</div>
400
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]401<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]402
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]403<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]404<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]405<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]406
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]407<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]408
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]409<p>LLVM identifiers come in two basic types: global and local. Global
410 identifiers (functions, global variables) begin with the <tt>'@'</tt>
411 character. Local identifiers (register names, types) begin with
412 the <tt>'%'</tt> character. Additionally, there are three different formats
413 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]414
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]415<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]416 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]417 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
418 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
419 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
420 other characters in their names can be surrounded with quotes. Special
421 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
422 ASCII code for the character in hexadecimal. In this way, any character
423 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]425 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]427
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]428 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]429 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]430</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]432<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]433 don't need to worry about name clashes with reserved words, and the set of
434 reserved words may be expanded in the future without penalty. Additionally,
435 unnamed identifiers allow a compiler to quickly come up with a temporary
436 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]438<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]439 languages. There are keywords for different opcodes
440 ('<tt><a href="#i_add">add</a></tt>',
441 '<tt><a href="#i_bitcast">bitcast</a></tt>',
442 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
443 ('<tt><a href="#t_void">void</a></tt>',
444 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
445 reserved words cannot conflict with variable names, because none of them
446 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
448<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]449 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]451<p>The easy way:</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_mul">mul</a> i32 %X, 8
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>After strength reduction:</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">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]460%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
462
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]463<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]465<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]466%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
467%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]468%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469</pre>
470
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
472 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]474<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]476 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]477
478 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]479 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]481 <li>Unnamed temporaries are numbered sequentially</li>
482</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]483
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]484<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]485 demonstrating instructions, we will follow an instruction with a comment that
486 defines the type and name of value produced. Comments are shown in italic
487 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]488
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]489</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]490
491<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]492<h2><a name="highlevel">High Level Structure</a></h2>
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<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]496<h3>
497 <a name="modulestructure">Module Structure</a>
498</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]500<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]502<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
503 translation unit of the input programs. Each module consists of functions,
504 global variables, and symbol table entries. Modules may be combined together
505 with the LLVM linker, which merges function (and global variable)
506 definitions, resolves forward declarations, and merges symbol table
507 entries. Here is an example of the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]508
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]509<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]510<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]511<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]512
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]513<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]514<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]515
516<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]517define i32 @main() { <i>; i32()* </i>&nbsp;
518 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]519 %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]520
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]521 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]522 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]523 <a href="#i_ret">ret</a> i32 0&nbsp;
524}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]525
526<i>; Named metadata</i>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]527!1 = metadata !{i32 42}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]528!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]529</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]530
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]531<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]532 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]533 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]534 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]535 "<tt>foo</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]536
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]537<p>In general, a module is made up of a list of global values (where both
538 functions and global variables are global values). Global values are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539 represented by a pointer to a memory location (in this case, a pointer to an
540 array of char, and a pointer to a function), and have one of the
541 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]542
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]543</div>
544
545<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]546<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]547 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]548</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]549
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]550<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]551
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]552<p>All Global Variables and Functions have one of the following types of
553 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]554
555<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]557 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
558 by objects in the current module. In particular, linking code into a
559 module with an private global value may cause the private to be renamed as
560 necessary to avoid collisions. Because the symbol is private to the
561 module, all references can be updated. This doesn't show up in any symbol
562 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]563
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]565 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
566 assembler and evaluated by the linker. Unlike normal strong symbols, they
567 are removed by the linker from the final linked image (executable or
568 dynamic library).</dd>
569
570 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
571 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
572 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
573 linker. The symbols are removed by the linker from the final linked image
574 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]575
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]576 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
577 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
578 of the object is not taken. For instance, functions that had an inline
579 definition, but the compiler decided not to inline it. Note,
580 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
581 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
582 visibility. The symbols are removed by the linker from the final linked
583 image (executable or dynamic library).</dd>
584
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]586 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]587 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
588 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]589
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]591 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]592 into the object file corresponding to the LLVM module. They exist to
593 allow inlining and other optimizations to take place given knowledge of
594 the definition of the global, which is known to be somewhere outside the
595 module. Globals with <tt>available_externally</tt> linkage are allowed to
596 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
597 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]598
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]600 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]601 the same name when linkage occurs. This can be used to implement
602 some forms of inline functions, templates, or other code which must be
603 generated in each translation unit that uses it, but where the body may
604 be overridden with a more definitive definition later. Unreferenced
605 <tt>linkonce</tt> globals are allowed to be discarded. Note that
606 <tt>linkonce</tt> linkage does not actually allow the optimizer to
607 inline the body of this function into callers because it doesn't know if
608 this definition of the function is the definitive definition within the
609 program or whether it will be overridden by a stronger definition.
610 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
611 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]612
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]613 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
615 <tt>linkonce</tt> linkage, except that unreferenced globals with
616 <tt>weak</tt> linkage may not be discarded. This is used for globals that
617 are declared "weak" in C source code.</dd>
618
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]619 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]620 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
621 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
622 global scope.
623 Symbols with "<tt>common</tt>" linkage are merged in the same way as
624 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]625 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]626 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]627 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
628 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]629
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]630
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]631 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]632 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633 pointer to array type. When two global variables with appending linkage
634 are linked together, the two global arrays are appended together. This is
635 the LLVM, typesafe, equivalent of having the system linker append together
636 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]637
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 <dd>The semantics of this linkage follow the ELF object file model: the symbol
640 is weak until linked, if not linked, the symbol becomes null instead of
641 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]642
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
644 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]645 <dd>Some languages allow differing globals to be merged, such as two functions
646 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]647 that only equivalent globals are ever merged (the "one definition rule"
648 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]649 and <tt>weak_odr</tt> linkage types to indicate that the global will only
650 be merged with equivalent globals. These linkage types are otherwise the
651 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]652
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]653 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]654 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]655 visible, meaning that it participates in linkage and can be used to
656 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]657</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]658
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]659<p>The next two types of linkage are targeted for Microsoft Windows platform
660 only. They are designed to support importing (exporting) symbols from (to)
661 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]664 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]665 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]666 or variable via a global pointer to a pointer that is set up by the DLL
667 exporting the symbol. On Microsoft Windows targets, the pointer name is
668 formed by combining <code>__imp_</code> and the function or variable
669 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]670
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]671 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]672 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]673 pointer to a pointer in a DLL, so that it can be referenced with the
674 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
675 name is formed by combining <code>__imp_</code> and the function or
676 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</dl>
678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]679<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
680 another module defined a "<tt>.LC0</tt>" variable and was linked with this
681 one, one of the two would be renamed, preventing a collision. Since
682 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
683 declarations), they are accessible outside of the current module.</p>
684
685<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]686 other than <tt>external</tt>, <tt>dllimport</tt>
687 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]688
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]689<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]690 or <tt>weak_odr</tt> linkages.</p>
691
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]692</div>
693
694<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]695<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]696 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]697</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]698
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]699<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]702 and <a href="#i_invoke">invokes</a> can all have an optional calling
703 convention specified for the call. The calling convention of any pair of
704 dynamic caller/callee must match, or the behavior of the program is
705 undefined. The following calling conventions are supported by LLVM, and more
706 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707
708<dl>
709 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]710 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]711 specified) matches the target C calling conventions. This calling
712 convention supports varargs function calls and tolerates some mismatch in
713 the declared prototype and implemented declaration of the function (as
714 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]715
716 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]717 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]718 (e.g. by passing things in registers). This calling convention allows the
719 target to use whatever tricks it wants to produce fast code for the
720 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]721 (Application Binary Interface).
722 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]723 when this or the GHC convention is used.</a> This calling convention
724 does not support varargs and requires the prototype of all callees to
725 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]726
727 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]728 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]729 as possible under the assumption that the call is not commonly executed.
730 As such, these calls often preserve all registers so that the call does
731 not break any live ranges in the caller side. This calling convention
732 does not support varargs and requires the prototype of all callees to
733 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]734
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]735 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
736 <dd>This calling convention has been implemented specifically for use by the
737 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
738 It passes everything in registers, going to extremes to achieve this by
739 disabling callee save registers. This calling convention should not be
740 used lightly but only for specific situations such as an alternative to
741 the <em>register pinning</em> performance technique often used when
742 implementing functional programming languages.At the moment only X86
743 supports this convention and it has the following limitations:
744 <ul>
745 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
746 floating point types are supported.</li>
747 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
748 6 floating point parameters.</li>
749 </ul>
750 This calling convention supports
751 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
752 requires both the caller and callee are using it.
753 </dd>
754
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]755 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]756 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]757 target-specific calling conventions to be used. Target specific calling
758 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]759</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]760
761<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]762 support Pascal conventions or any other well-known target-independent
763 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]764
765</div>
766
767<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]768<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]770</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]772<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]773
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]774<p>All Global Variables and Functions have one of the following visibility
775 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
777<dl>
778 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]779 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]780 that the declaration is visible to other modules and, in shared libraries,
781 means that the declared entity may be overridden. On Darwin, default
782 visibility means that the declaration is visible to other modules. Default
783 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]784
785 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]786 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]787 object if they are in the same shared object. Usually, hidden visibility
788 indicates that the symbol will not be placed into the dynamic symbol
789 table, so no other module (executable or shared library) can reference it
790 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]791
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]792 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]793 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 the dynamic symbol table, but that references within the defining module
795 will bind to the local symbol. That is, the symbol cannot be overridden by
796 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]797</dl>
798
799</div>
800
801<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]802<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]803 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]804</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]806<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]807
808<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]809 it easier to read the IR and make the IR more condensed (particularly when
810 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]811
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]812<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]813%mytype = type { %mytype*, i32 }
814</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]815
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]816<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]817 "<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]818 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]819
820<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]821 and that you can therefore specify multiple names for the same type. This
822 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
823 uses structural typing, the name is not part of the type. When printing out
824 LLVM IR, the printer will pick <em>one name</em> to render all types of a
825 particular shape. This means that if you have code where two different
826 source types end up having the same LLVM type, that the dumper will sometimes
827 print the "wrong" or unexpected type. This is an important design point and
828 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]829
830</div>
831
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]832<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]833<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]834 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]835</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]837<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]838
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]839<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]840 instead of run-time. Global variables may optionally be initialized, may
841 have an explicit section to be placed in, and may have an optional explicit
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame]842 alignment specified.</p>
843
844<p>A variable may be defined as <tt>thread_local</tt>, which
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845 means that it will not be shared by threads (each thread will have a
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame]846 separated copy of the variable). Not all targets support thread-local
847 variables. Optionally, a TLS model may be specified:</p>
848
849<dl>
850 <dt><b><tt>localdynamic</tt></b>:</dt>
851 <dd>For variables that are only used within the current shared library.</dd>
852
853 <dt><b><tt>initialexec</tt></b>:</dt>
854 <dd>For variables in modules that will not be loaded dynamically.</dd>
855
856 <dt><b><tt>localexec</tt></b>:</dt>
857 <dd>For variables defined in the executable and only used within it.</dd>
858</dl>
859
860<p>The models correspond to the ELF TLS models; see
861 <a href="http://people.redhat.com/drepper/tls.pdf">ELF
862 Handling For Thread-Local Storage</a> for more information on under which
863 circumstances the different models may be used. The target may choose a
864 different TLS model if the specified model is not supported, or if a better
865 choice of model can be made.</p>
866
867<p>A variable may be defined as a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868 "constant," which indicates that the contents of the variable
869 will <b>never</b> be modified (enabling better optimization, allowing the
870 global data to be placed in the read-only section of an executable, etc).
871 Note that variables that need runtime initialization cannot be marked
872 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]873
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]874<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
875 constant, even if the final definition of the global is not. This capability
876 can be used to enable slightly better optimization of the program, but
877 requires the language definition to guarantee that optimizations based on the
878 'constantness' are valid for the translation units that do not include the
879 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]880
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]881<p>As SSA values, global variables define pointer values that are in scope
882 (i.e. they dominate) all basic blocks in the program. Global variables
883 always define a pointer to their "content" type because they describe a
884 region of memory, and all memory objects in LLVM are accessed through
885 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]886
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]887<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
888 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]889 like this can be merged with other constants if they have the same
890 initializer. Note that a constant with significant address <em>can</em>
891 be merged with a <tt>unnamed_addr</tt> constant, the result being a
892 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]894<p>A global variable may be declared to reside in a target-specific numbered
895 address space. For targets that support them, address spaces may affect how
896 optimizations are performed and/or what target instructions are used to
897 access the variable. The default address space is zero. The address space
898 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]899
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]900<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]901 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]902
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]903<p>An explicit alignment may be specified for a global, which must be a power
904 of 2. If not present, or if the alignment is set to zero, the alignment of
905 the global is set by the target to whatever it feels convenient. If an
906 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]907 alignment. Targets and optimizers are not allowed to over-align the global
908 if the global has an assigned section. In this case, the extra alignment
909 could be observable: for example, code could assume that the globals are
910 densely packed in their section and try to iterate over them as an array,
911 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]912
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]913<p>For example, the following defines a global in a numbered address space with
914 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]915
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]916<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]917@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]918</pre>
919
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame]920<p>The following example defines a thread-local global with
921 the <tt>initialexec</tt> TLS model:</p>
922
923<pre class="doc_code">
924@G = thread_local(initialexec) global i32 0, align 4
925</pre>
926
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]927</div>
928
929
930<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]931<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]932 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]933</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]935<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]936
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]937<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]938 optional <a href="#linkage">linkage type</a>, an optional
939 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]940 <a href="#callingconv">calling convention</a>,
941 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942 <a href="#paramattrs">parameter attribute</a> for the return type, a function
943 name, a (possibly empty) argument list (each with optional
944 <a href="#paramattrs">parameter attributes</a>), optional
945 <a href="#fnattrs">function attributes</a>, an optional section, an optional
946 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
947 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]948
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]949<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
950 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]951 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]952 <a href="#callingconv">calling convention</a>,
953 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954 <a href="#paramattrs">parameter attribute</a> for the return type, a function
955 name, a possibly empty list of arguments, an optional alignment, and an
956 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]957
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]958<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]959 (Control Flow Graph) for the function. Each basic block may optionally start
960 with a label (giving the basic block a symbol table entry), contains a list
961 of instructions, and ends with a <a href="#terminators">terminator</a>
962 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]963
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]964<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]965 executed on entrance to the function, and it is not allowed to have
966 predecessor basic blocks (i.e. there can not be any branches to the entry
967 block of a function). Because the block can have no predecessors, it also
968 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]969
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]970<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]972
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]973<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]974 the alignment is set to zero, the alignment of the function is set by the
975 target to whatever it feels convenient. If an explicit alignment is
976 specified, the function is forced to have at least that much alignment. All
977 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]978
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]979<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]980 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]981
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]982<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]983<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]984define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]985 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
986 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
987 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
988 [<a href="#gc">gc</a>] { ... }
989</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]990
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]991</div>
992
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]993<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]994<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]995 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]996</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]997
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]998<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]999
1000<p>Aliases act as "second name" for the aliasee value (which can be either
1001 function, global variable, another alias or bitcast of global value). Aliases
1002 may have an optional <a href="#linkage">linkage type</a>, and an
1003 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]1004
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1005<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1006<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]1007@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1008</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]1009
1010</div>
1011
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1012<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1013<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1014 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1015</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1016
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1017<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1018
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]1019<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1020 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]1021 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1022
1023<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1024<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1025; Some unnamed metadata nodes, which are referenced by the named metadata.
1026!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1027!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1028!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]1029; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1030!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1031</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1032
1033</div>
1034
1035<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1036<h3>
1037 <a name="paramattrs">Parameter Attributes</a>
1038</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1039
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1040<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041
1042<p>The return type and each parameter of a function type may have a set of
1043 <i>parameter attributes</i> associated with them. Parameter attributes are
1044 used to communicate additional information about the result or parameters of
1045 a function. Parameter attributes are considered to be part of the function,
1046 not of the function type, so functions with different parameter attributes
1047 can have the same function type.</p>
1048
1049<p>Parameter attributes are simple keywords that follow the type specified. If
1050 multiple parameter attributes are needed, they are space separated. For
1051 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1052
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1053<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1054declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1055declare i32 @atoi(i8 zeroext)
1056declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1057</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1058
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1060 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1061
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1062<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1063
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1065 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1067 should be zero-extended to the extent required by the target's ABI (which
1068 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1069 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1070
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1071 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1072 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1073 should be sign-extended to the extent required by the target's ABI (which
1074 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1075 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1076
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1077 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078 <dd>This indicates that this parameter or return value should be treated in a
1079 special target-dependent fashion during while emitting code for a function
1080 call or return (usually, by putting it in a register as opposed to memory,
1081 though some targets use it to distinguish between two different kinds of
1082 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1083
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1084 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1085 <dd><p>This indicates that the pointer parameter should really be passed by
1086 value to the function. The attribute implies that a hidden copy of the
1087 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088 is made between the caller and the callee, so the callee is unable to
Chris Lattneref097052012-05-30 00:40:23 +0000[diff] [blame]1089 modify the value in the caller. This attribute is only valid on LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1090 pointer arguments. It is generally used to pass structs and arrays by
1091 value, but is also valid on pointers to scalars. The copy is considered
1092 to belong to the caller not the callee (for example,
1093 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1094 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1095 values.</p>
1096
1097 <p>The byval attribute also supports specifying an alignment with
1098 the align attribute. It indicates the alignment of the stack slot to
1099 form and the known alignment of the pointer specified to the call site. If
1100 the alignment is not specified, then the code generator makes a
1101 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1102
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1103 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This indicates that the pointer parameter specifies the address of a
1105 structure that is the return value of the function in the source program.
1106 This pointer must be guaranteed by the caller to be valid: loads and
1107 stores to the structure may be assumed by the callee to not to trap. This
1108 may only be applied to the first parameter. This is not a valid attribute
1109 for return values. </dd>
1110
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1111 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1112 <dd>This indicates that pointer values
1113 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1114 value do not alias pointer values which are not <i>based</i> on it,
1115 ignoring certain "irrelevant" dependencies.
1116 For a call to the parent function, dependencies between memory
1117 references from before or after the call and from those during the call
1118 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1119 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1120 The caller shares the responsibility with the callee for ensuring that
1121 these requirements are met.
1122 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1123 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1124<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1125 Note that this definition of <tt>noalias</tt> is intentionally
1126 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1127 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1128<br>
1129 For function return values, C99's <tt>restrict</tt> is not meaningful,
1130 while LLVM's <tt>noalias</tt> is.
1131 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1132
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1133 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This indicates that the callee does not make any copies of the pointer
1135 that outlive the callee itself. This is not a valid attribute for return
1136 values.</dd>
1137
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1138 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This indicates that the pointer parameter can be excised using the
1140 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1141 attribute for return values.</dd>
1142</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1143
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1144</div>
1145
1146<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1147<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1148 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1149</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1150
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1151<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1152
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1153<p>Each function may specify a garbage collector name, which is simply a
1154 string:</p>
1155
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1156<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1157define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1158</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1159
1160<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 collector which will cause the compiler to alter its output in order to
1162 support the named garbage collection algorithm.</p>
1163
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1164</div>
1165
1166<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1167<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1168 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1169</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1170
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1171<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1172
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1173<p>Function attributes are set to communicate additional information about a
1174 function. Function attributes are considered to be part of the function, not
1175 of the function type, so functions with different parameter attributes can
1176 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1177
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1178<p>Function attributes are simple keywords that follow the type specified. If
1179 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1180
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1181<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1182define void @f() noinline { ... }
1183define void @f() alwaysinline { ... }
1184define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1185define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1186</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1187
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1188<dl>
Kostya Serebryany164b86b2012-01-20 17:56:17 +0000[diff] [blame]1189 <dt><tt><b>address_safety</b></tt></dt>
1190 <dd>This attribute indicates that the address safety analysis
1191 is enabled for this function. </dd>
1192
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1193 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1194 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1195 the backend should forcibly align the stack pointer. Specify the
1196 desired alignment, which must be a power of two, in parentheses.
1197
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1198 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1199 <dd>This attribute indicates that the inliner should attempt to inline this
1200 function into callers whenever possible, ignoring any active inlining size
1201 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1202
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1203 <dt><tt><b>nonlazybind</b></tt></dt>
1204 <dd>This attribute suppresses lazy symbol binding for the function. This
1205 may make calls to the function faster, at the cost of extra program
1206 startup time if the function is not called during program startup.</dd>
1207
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1208 <dt><tt><b>inlinehint</b></tt></dt>
1209 <dd>This attribute indicates that the source code contained a hint that inlining
1210 this function is desirable (such as the "inline" keyword in C/C++). It
1211 is just a hint; it imposes no requirements on the inliner.</dd>
1212
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1213 <dt><tt><b>naked</b></tt></dt>
1214 <dd>This attribute disables prologue / epilogue emission for the function.
1215 This can have very system-specific consequences.</dd>
1216
1217 <dt><tt><b>noimplicitfloat</b></tt></dt>
1218 <dd>This attributes disables implicit floating point instructions.</dd>
1219
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1220 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1221 <dd>This attribute indicates that the inliner should never inline this
1222 function in any situation. This attribute may not be used together with
1223 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1224
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1225 <dt><tt><b>noredzone</b></tt></dt>
1226 <dd>This attribute indicates that the code generator should not use a red
1227 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1228
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This function attribute indicates that the function never returns
1231 normally. This produces undefined behavior at runtime if the function
1232 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1233
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1234 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1235 <dd>This function attribute indicates that the function never returns with an
1236 unwind or exceptional control flow. If the function does unwind, its
1237 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1238
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1239 <dt><tt><b>optsize</b></tt></dt>
1240 <dd>This attribute suggests that optimization passes and code generator passes
1241 make choices that keep the code size of this function low, and otherwise
1242 do optimizations specifically to reduce code size.</dd>
1243
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1244 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1245 <dd>This attribute indicates that the function computes its result (or decides
1246 to unwind an exception) based strictly on its arguments, without
1247 dereferencing any pointer arguments or otherwise accessing any mutable
1248 state (e.g. memory, control registers, etc) visible to caller functions.
1249 It does not write through any pointer arguments
1250 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1251 changes any state visible to callers. This means that it cannot unwind
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1252 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1253
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1254 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1255 <dd>This attribute indicates that the function does not write through any
1256 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1257 arguments) or otherwise modify any state (e.g. memory, control registers,
1258 etc) visible to caller functions. It may dereference pointer arguments
1259 and read state that may be set in the caller. A readonly function always
1260 returns the same value (or unwinds an exception identically) when called
1261 with the same set of arguments and global state. It cannot unwind an
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1262 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1263
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1264 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1265 <dd>This attribute indicates that this function can return twice. The
1266 C <code>setjmp</code> is an example of such a function. The compiler
1267 disables some optimizations (like tail calls) in the caller of these
1268 functions.</dd>
1269
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1270 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1271 <dd>This attribute indicates that the function should emit a stack smashing
1272 protector. It is in the form of a "canary"&mdash;a random value placed on
1273 the stack before the local variables that's checked upon return from the
1274 function to see if it has been overwritten. A heuristic is used to
1275 determine if a function needs stack protectors or not.<br>
1276<br>
1277 If a function that has an <tt>ssp</tt> attribute is inlined into a
1278 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1279 function will have an <tt>ssp</tt> attribute.</dd>
1280
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1281 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <dd>This attribute indicates that the function should <em>always</em> emit a
1283 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1284 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1285<br>
1286 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1287 function that doesn't have an <tt>sspreq</tt> attribute or which has
1288 an <tt>ssp</tt> attribute, then the resulting function will have
1289 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1290
1291 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1292 <dd>This attribute indicates that the ABI being targeted requires that
1293 an unwind table entry be produce for this function even if we can
1294 show that no exceptions passes by it. This is normally the case for
1295 the ELF x86-64 abi, but it can be disabled for some compilation
1296 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1297</dl>
1298
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1299</div>
1300
1301<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1302<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1303 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1304</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1305
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1306<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307
1308<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1309 the GCC "file scope inline asm" blocks. These blocks are internally
1310 concatenated by LLVM and treated as a single unit, but may be separated in
1311 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1312
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1313<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1314module asm "inline asm code goes here"
1315module asm "more can go here"
1316</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1317
1318<p>The strings can contain any character by escaping non-printable characters.
1319 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]1320 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1321
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1322<p>The inline asm code is simply printed to the machine code .s file when
1323 assembly code is generated.</p>
1324
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1325</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1326
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1327<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1328<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1329 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1330</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1331
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1332<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1335 data is to be laid out in memory. The syntax for the data layout is
1336 simply:</p>
1337
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1338<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339target datalayout = "<i>layout specification</i>"
1340</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1341
1342<p>The <i>layout specification</i> consists of a list of specifications
1343 separated by the minus sign character ('-'). Each specification starts with
1344 a letter and may include other information after the letter to define some
1345 aspect of the data layout. The specifications accepted are as follows:</p>
1346
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1347<dl>
1348 <dt><tt>E</tt></dt>
1349 <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]1350 bits with the most significance have the lowest address location.</dd>
1351
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1352 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1353 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1354 the bits with the least significance have the lowest address
1355 location.</dd>
1356
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1357 <dt><tt>S<i>size</i></tt></dt>
1358 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1359 of stack variables is limited to the natural stack alignment to avoid
1360 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1361 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1362 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1363
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1364 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1365 <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]1366 <i>preferred</i> alignments. All sizes are in bits. Specifying
1367 the <i>pref</i> alignment is optional. If omitted, the
1368 preceding <tt>:</tt> should be omitted too.</dd>
1369
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1370 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1371 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1372 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1373
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1374 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1375 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1376 <i>size</i>.</dd>
1377
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1378 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1379 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1380 <i>size</i>. Only values of <i>size</i> that are supported by the target
1381 will work. 32 (float) and 64 (double) are supported on all targets;
1382 80 or 128 (different flavors of long double) are also supported on some
1383 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1384
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1385 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1386 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1387 <i>size</i>.</dd>
1388
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1389 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1390 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1391 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1392
1393 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1394 <dd>This specifies a set of native integer widths for the target CPU
1395 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1396 "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]1397 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1398 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1399</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1400
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1401<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1402 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1403 specifications in the <tt>datalayout</tt> keyword. The default specifications
1404 are given in this list:</p>
1405
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1406<ul>
1407 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1408 <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]1409 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1410 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1411 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1412 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1413 <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]1414 alignment of 64-bits</li>
1415 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1416 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1417 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1418 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1419 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1420 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1421</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1422
1423<p>When LLVM is determining the alignment for a given type, it uses the
1424 following rules:</p>
1425
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1426<ol>
1427 <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]1428 specification is used.</li>
1429
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1430 <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]1431 smallest integer type that is larger than the bitwidth of the sought type
1432 is used. If none of the specifications are larger than the bitwidth then
1433 the the largest integer type is used. For example, given the default
1434 specifications above, the i7 type will use the alignment of i8 (next
1435 largest) while both i65 and i256 will use the alignment of i64 (largest
1436 specified).</li>
1437
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1438 <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]1439 largest vector type that is smaller than the sought vector type will be
1440 used as a fall back. This happens because &lt;128 x double&gt; can be
1441 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1442</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1443
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1444<p>The function of the data layout string may not be what you expect. Notably,
1445 this is not a specification from the frontend of what alignment the code
1446 generator should use.</p>
1447
1448<p>Instead, if specified, the target data layout is required to match what the
1449 ultimate <em>code generator</em> expects. This string is used by the
1450 mid-level optimizers to
1451 improve code, and this only works if it matches what the ultimate code
1452 generator uses. If you would like to generate IR that does not embed this
1453 target-specific detail into the IR, then you don't have to specify the
1454 string. This will disable some optimizations that require precise layout
1455 information, but this also prevents those optimizations from introducing
1456 target specificity into the IR.</p>
1457
1458
1459
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1460</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1461
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1462<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1463<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1464 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1465</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1466
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1467<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1468
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1469<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1470with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1471is undefined. Pointer values are associated with address ranges
1472according to the following rules:</p>
1473
1474<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1475 <li>A pointer value is associated with the addresses associated with
1476 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1477 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1478 range of the variable's storage.</li>
1479 <li>The result value of an allocation instruction is associated with
1480 the address range of the allocated storage.</li>
1481 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1482 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1483 <li>An integer constant other than zero or a pointer value returned
1484 from a function not defined within LLVM may be associated with address
1485 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1486 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1487 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1488</ul>
1489
1490<p>A pointer value is <i>based</i> on another pointer value according
1491 to the following rules:</p>
1492
1493<ul>
1494 <li>A pointer value formed from a
1495 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1496 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1497 <li>The result value of a
1498 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1499 of the <tt>bitcast</tt>.</li>
1500 <li>A pointer value formed by an
1501 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1502 pointer values that contribute (directly or indirectly) to the
1503 computation of the pointer's value.</li>
1504 <li>The "<i>based</i> on" relationship is transitive.</li>
1505</ul>
1506
1507<p>Note that this definition of <i>"based"</i> is intentionally
1508 similar to the definition of <i>"based"</i> in C99, though it is
1509 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1510
1511<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1512<tt><a href="#i_load">load</a></tt> merely indicates the size and
1513alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1514interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1515<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1516and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1517
1518<p>Consequently, type-based alias analysis, aka TBAA, aka
1519<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1520LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1521additional information which specialized optimization passes may use
1522to implement type-based alias analysis.</p>
1523
1524</div>
1525
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1526<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1527<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1528 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1529</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1530
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1531<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1532
1533<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1534href="#i_store"><tt>store</tt></a>s, and <a
1535href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1536The optimizers must not change the number of volatile operations or change their
1537order of execution relative to other volatile operations. The optimizers
1538<i>may</i> change the order of volatile operations relative to non-volatile
1539operations. This is not Java's "volatile" and has no cross-thread
1540synchronization behavior.</p>
1541
1542</div>
1543
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1544<!-- ======================================================================= -->
1545<h3>
1546 <a name="memmodel">Memory Model for Concurrent Operations</a>
1547</h3>
1548
1549<div>
1550
1551<p>The LLVM IR does not define any way to start parallel threads of execution
1552or to register signal handlers. Nonetheless, there are platform-specific
1553ways to create them, and we define LLVM IR's behavior in their presence. This
1554model is inspired by the C++0x memory model.</p>
1555
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1556<p>For a more informal introduction to this model, see the
1557<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1558
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1559<p>We define a <i>happens-before</i> partial order as the least partial order
1560that</p>
1561<ul>
1562 <li>Is a superset of single-thread program order, and</li>
1563 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1564 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1565 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1566 creation, thread joining, etc., and by atomic instructions.
1567 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1568 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1569</ul>
1570
1571<p>Note that program order does not introduce <i>happens-before</i> edges
1572between a thread and signals executing inside that thread.</p>
1573
1574<p>Every (defined) read operation (load instructions, memcpy, atomic
1575loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1576(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1577stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1578initialized globals are considered to have a write of the initializer which is
1579atomic and happens before any other read or write of the memory in question.
1580For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1581any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1582
1583<ul>
1584 <li>If <var>write<sub>1</sub></var> happens before
1585 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1586 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1587 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1588 <li>If <var>R<sub>byte</sub></var> happens before
1589 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1590 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1591</ul>
1592
1593<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1594<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1595 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1596 is supposed to give guarantees which can support
1597 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1598 addresses which do not behave like normal memory. It does not generally
1599 provide cross-thread synchronization.)
1600 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1601 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1602 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1603 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1604 <var>R<sub>byte</sub></var> returns the value written by that
1605 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1606 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1607 <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]1608 values written. See the <a href="#ordering">Atomic Memory Ordering
1609 Constraints</a> section for additional constraints on how the choice
1610 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1611 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1612</ul>
1613
1614<p><var>R</var> returns the value composed of the series of bytes it read.
1615This implies that some bytes within the value may be <tt>undef</tt>
1616<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1617defines the semantics of the operation; it doesn't mean that targets will
1618emit more than one instruction to read the series of bytes.</p>
1619
1620<p>Note that in cases where none of the atomic intrinsics are used, this model
1621places only one restriction on IR transformations on top of what is required
1622for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1623otherwise be stored is not allowed in general. (Specifically, in the case
1624where another thread might write to and read from an address, introducing a
1625store can change a load that may see exactly one write into a load that may
1626see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1627
1628<!-- FIXME: This model assumes all targets where concurrency is relevant have
1629a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1630none of the backends currently in the tree fall into this category; however,
1631there might be targets which care. If there are, we want a paragraph
1632like the following:
1633
1634Targets may specify that stores narrower than a certain width are not
1635available; on such a target, for the purposes of this model, treat any
1636non-atomic write with an alignment or width less than the minimum width
1637as if it writes to the relevant surrounding bytes.
1638-->
1639
1640</div>
1641
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1642<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1643<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1644 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1645</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1646
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1647<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1648
1649<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1650<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1651<a href="#i_fence"><code>fence</code></a>,
1652<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1653<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1654that determines which other atomic instructions on the same address they
1655<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1656but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1657check those specs (see spec references in the
Nick Lewycky300a2632012-01-23 08:47:21 +0000[diff] [blame]1658<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1659<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1660treat these orderings somewhat differently since they don't take an address.
1661See that instruction's documentation for details.</p>
1662
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1663<p>For a simpler introduction to the ordering constraints, see the
1664<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1665
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1666<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1667<dt><code>unordered</code></dt>
1668<dd>The set of values that can be read is governed by the happens-before
1669partial order. A value cannot be read unless some operation wrote it.
1670This is intended to provide a guarantee strong enough to model Java's
1671non-volatile shared variables. This ordering cannot be specified for
1672read-modify-write operations; it is not strong enough to make them atomic
1673in any interesting way.</dd>
1674<dt><code>monotonic</code></dt>
1675<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1676total order for modifications by <code>monotonic</code> operations on each
1677address. All modification orders must be compatible with the happens-before
1678order. There is no guarantee that the modification orders can be combined to
1679a global total order for the whole program (and this often will not be
1680possible). The read in an atomic read-modify-write operation
1681(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1682<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1683reads the value in the modification order immediately before the value it
1684writes. If one atomic read happens before another atomic read of the same
1685address, the later read must see the same value or a later value in the
1686address's modification order. This disallows reordering of
1687<code>monotonic</code> (or stronger) operations on the same address. If an
1688address is written <code>monotonic</code>ally by one thread, and other threads
1689<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1690eventually see the write. This corresponds to the C++0x/C1x
1691<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1692<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1693<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1694a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1695operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1696<dt><code>release</code></dt>
1697<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1698writes a value which is subsequently read by an <code>acquire</code> operation,
1699it <i>synchronizes-with</i> that operation. (This isn't a complete
1700description; see the C++0x definition of a release sequence.) This corresponds
1701to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1702<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1703<code>acquire</code> and <code>release</code> operation on its address.
1704This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1705<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1706<dd>In addition to the guarantees of <code>acq_rel</code>
1707(<code>acquire</code> for an operation which only reads, <code>release</code>
1708for an operation which only writes), there is a global total order on all
1709sequentially-consistent operations on all addresses, which is consistent with
1710the <i>happens-before</i> partial order and with the modification orders of
1711all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1712preceding write to the same address in this global order. This corresponds
1713to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1714</dl>
1715
1716<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1717it only <i>synchronizes with</i> or participates in modification and seq_cst
1718total orderings with other operations running in the same thread (for example,
1719in signal handlers).</p>
1720
1721</div>
1722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1723</div>
1724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1726<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1727<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1728
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1729<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1731<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1732 intermediate representation. Being typed enables a number of optimizations
1733 to be performed on the intermediate representation directly, without having
1734 to do extra analyses on the side before the transformation. A strong type
1735 system makes it easier to read the generated code and enables novel analyses
1736 and transformations that are not feasible to perform on normal three address
1737 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1738
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1739<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1740<h3>
1741 <a name="t_classifications">Type Classifications</a>
1742</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1743
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1744<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1745
1746<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
1748<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1749 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1750 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1752 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1753 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1754 </tr>
1755 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1756 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1757 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758 </tr>
1759 <tr>
1760 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1761 <td><a href="#t_integer">integer</a>,
1762 <a href="#t_floating">floating point</a>,
1763 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1764 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1765 <a href="#t_struct">structure</a>,
1766 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1767 <a href="#t_label">label</a>,
1768 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1769 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1770 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1771 <tr>
1772 <td><a href="#t_primitive">primitive</a></td>
1773 <td><a href="#t_label">label</a>,
1774 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1775 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1776 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1777 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1778 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1779 </tr>
1780 <tr>
1781 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1782 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1783 <a href="#t_function">function</a>,
1784 <a href="#t_pointer">pointer</a>,
1785 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1786 <a href="#t_vector">vector</a>,
1787 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1788 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1789 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1790 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1791</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1792
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1793<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1794 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1795 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1796
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1797</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1798
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1799<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1800<h3>
1801 <a name="t_primitive">Primitive Types</a>
1802</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1803
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1804<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1806<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1808
1809<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1810<h4>
1811 <a name="t_integer">Integer Type</a>
1812</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1813
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1814<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1815
1816<h5>Overview:</h5>
1817<p>The integer type is a very simple type that simply specifies an arbitrary
1818 bit width for the integer type desired. Any bit width from 1 bit to
1819 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1820
1821<h5>Syntax:</h5>
1822<pre>
1823 iN
1824</pre>
1825
1826<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1827 value.</p>
1828
1829<h5>Examples:</h5>
1830<table class="layout">
1831 <tr class="layout">
1832 <td class="left"><tt>i1</tt></td>
1833 <td class="left">a single-bit integer.</td>
1834 </tr>
1835 <tr class="layout">
1836 <td class="left"><tt>i32</tt></td>
1837 <td class="left">a 32-bit integer.</td>
1838 </tr>
1839 <tr class="layout">
1840 <td class="left"><tt>i1942652</tt></td>
1841 <td class="left">a really big integer of over 1 million bits.</td>
1842 </tr>
1843</table>
1844
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1845</div>
1846
1847<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1848<h4>
1849 <a name="t_floating">Floating Point Types</a>
1850</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1852<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1853
1854<table>
1855 <tbody>
1856 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1857 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1858 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1859 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1860 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1861 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1862 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1863 </tbody>
1864</table>
1865
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1866</div>
1867
1868<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1869<h4>
1870 <a name="t_x86mmx">X86mmx Type</a>
1871</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1872
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1873<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1874
1875<h5>Overview:</h5>
1876<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>
1877
1878<h5>Syntax:</h5>
1879<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1880 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1881</pre>
1882
1883</div>
1884
1885<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1886<h4>
1887 <a name="t_void">Void Type</a>
1888</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1889
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1890<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1891
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1892<h5>Overview:</h5>
1893<p>The void type does not represent any value and has no size.</p>
1894
1895<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1896<pre>
1897 void
1898</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1899
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1900</div>
1901
1902<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1903<h4>
1904 <a name="t_label">Label Type</a>
1905</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1906
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1907<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1908
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1909<h5>Overview:</h5>
1910<p>The label type represents code labels.</p>
1911
1912<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1913<pre>
1914 label
1915</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1916
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1917</div>
1918
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1919<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1920<h4>
1921 <a name="t_metadata">Metadata Type</a>
1922</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1923
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1924<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1925
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1926<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1927<p>The metadata type represents embedded metadata. No derived types may be
1928 created from metadata except for <a href="#t_function">function</a>
1929 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1930
1931<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1932<pre>
1933 metadata
1934</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1935
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1936</div>
1937
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1938</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1939
1940<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1941<h3>
1942 <a name="t_derived">Derived Types</a>
1943</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1944
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1945<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1946
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1947<p>The real power in LLVM comes from the derived types in the system. This is
1948 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1949 useful types. Each of these types contain one or more element types which
1950 may be a primitive type, or another derived type. For example, it is
1951 possible to have a two dimensional array, using an array as the element type
1952 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1953
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1954<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1955<h4>
1956 <a name="t_aggregate">Aggregate Types</a>
1957</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1958
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1959<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1960
1961<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1962 member types. <a href="#t_array">Arrays</a> and
1963 <a href="#t_struct">structs</a> are aggregate types.
1964 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1965
1966</div>
1967
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1968<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1969<h4>
1970 <a name="t_array">Array Type</a>
1971</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1972
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1973<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1976<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1977 sequentially in memory. The array type requires a size (number of elements)
1978 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1979
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1980<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1981<pre>
1982 [&lt;# elements&gt; x &lt;elementtype&gt;]
1983</pre>
1984
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1985<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1986 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1987
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1988<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1989<table class="layout">
1990 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1991 <td class="left"><tt>[40 x i32]</tt></td>
1992 <td class="left">Array of 40 32-bit integer values.</td>
1993 </tr>
1994 <tr class="layout">
1995 <td class="left"><tt>[41 x i32]</tt></td>
1996 <td class="left">Array of 41 32-bit integer values.</td>
1997 </tr>
1998 <tr class="layout">
1999 <td class="left"><tt>[4 x i8]</tt></td>
2000 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2001 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2002</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2003<p>Here are some examples of multidimensional arrays:</p>
2004<table class="layout">
2005 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2006 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
2007 <td class="left">3x4 array of 32-bit integer values.</td>
2008 </tr>
2009 <tr class="layout">
2010 <td class="left"><tt>[12 x [10 x float]]</tt></td>
2011 <td class="left">12x10 array of single precision floating point values.</td>
2012 </tr>
2013 <tr class="layout">
2014 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
2015 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2016 </tr>
2017</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2018
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]2019<p>There is no restriction on indexing beyond the end of the array implied by
2020 a static type (though there are restrictions on indexing beyond the bounds
2021 of an allocated object in some cases). This means that single-dimension
2022 'variable sized array' addressing can be implemented in LLVM with a zero
2023 length array type. An implementation of 'pascal style arrays' in LLVM could
2024 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2025
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2026</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2027
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2028<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2029<h4>
2030 <a name="t_function">Function Type</a>
2031</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2032
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2033<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2035<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2036<p>The function type can be thought of as a function signature. It consists of
2037 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]2038 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]2039
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2041<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2042 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2043</pre>
2044
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2045<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]2046 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2047 which indicates that the function takes a variable number of arguments.
2048 Variable argument functions can access their arguments with
2049 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2050 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2051 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2052
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2053<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2054<table class="layout">
2055 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2056 <td class="left"><tt>i32 (i32)</tt></td>
2057 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2058 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2059 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2060 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2061 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2062 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2063 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2064 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2065 </td>
2066 </tr><tr class="layout">
2067 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2068 <td class="left">A vararg function that takes at least one
2069 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2070 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2071 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2072 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2073 </tr><tr class="layout">
2074 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2075 <td class="left">A function taking an <tt>i32</tt>, returning a
2076 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2077 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2078 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2079</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2080
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2081</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2082
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2083<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2084<h4>
2085 <a name="t_struct">Structure Type</a>
2086</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2087
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2088<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2089
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2090<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2091<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2092 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]2093
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2094<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2095 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2096 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2097 Structures in registers are accessed using the
2098 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2099 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2100
2101<p>Structures may optionally be "packed" structures, which indicate that the
2102 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2103 the elements. In non-packed structs, padding between field types is inserted
2104 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2105 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2106
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2107<p>Structures can either be "literal" or "identified". A literal structure is
2108 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2109 types are always defined at the top level with a name. Literal types are
2110 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2111 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]2112 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2113</p>
2114
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2115<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2116<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2117 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2118 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2119</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2120
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2122<table class="layout">
2123 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2124 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2125 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2126 </tr>
2127 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2128 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2129 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2130 second element is a <a href="#t_pointer">pointer</a> to a
2131 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2132 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2133 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2134 <tr class="layout">
2135 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2136 <td class="left">A packed struct known to be 5 bytes in size.</td>
2137 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2138</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2139
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2140</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2141
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2142<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2143<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2144 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2145</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2146
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2147<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2148
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2149<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2150<p>Opaque structure types are used to represent named structure types that do
2151 not have a body specified. This corresponds (for example) to the C notion of
2152 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2153
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2154<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2155<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2156 %X = type opaque
2157 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2158</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2159
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2160<h5>Examples:</h5>
2161<table class="layout">
2162 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2163 <td class="left"><tt>opaque</tt></td>
2164 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2165 </tr>
2166</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2167
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2168</div>
2169
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2170
2171
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2172<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2173<h4>
2174 <a name="t_pointer">Pointer Type</a>
2175</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2176
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2177<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2178
2179<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2180<p>The pointer type is used to specify memory locations.
2181 Pointers are commonly used to reference objects in memory.</p>
2182
2183<p>Pointer types may have an optional address space attribute defining the
2184 numbered address space where the pointed-to object resides. The default
2185 address space is number zero. The semantics of non-zero address
2186 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2187
2188<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2189 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2190
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2191<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2192<pre>
2193 &lt;type&gt; *
2194</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2195
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2196<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2197<table class="layout">
2198 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2199 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2200 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2201 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2202 </tr>
2203 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2204 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2205 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2206 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2207 <tt>i32</tt>.</td>
2208 </tr>
2209 <tr class="layout">
2210 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2211 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2212 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2213 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2214</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2216</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2217
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2218<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2219<h4>
2220 <a name="t_vector">Vector Type</a>
2221</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2222
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2223<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2224
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2225<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2226<p>A vector type is a simple derived type that represents a vector of elements.
2227 Vector types are used when multiple primitive data are operated in parallel
2228 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2229 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2230 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2231
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2232<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2233<pre>
2234 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2235</pre>
2236
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2237<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2238 may be any integer or floating point type, or a pointer to these types.
2239 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2240
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2241<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2242<table class="layout">
2243 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2244 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2245 <td class="left">Vector of 4 32-bit integer values.</td>
2246 </tr>
2247 <tr class="layout">
2248 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2249 <td class="left">Vector of 8 32-bit floating-point values.</td>
2250 </tr>
2251 <tr class="layout">
2252 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2253 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2254 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2255 <tr class="layout">
2256 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2257 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2258 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2259</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2260
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2261</div>
2262
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2263</div>
2264
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2265</div>
2266
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2267<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2268<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2269<!-- *********************************************************************** -->
2270
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2271<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2272
2273<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2274 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2275
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2276<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2277<h3>
2278 <a name="simpleconstants">Simple Constants</a>
2279</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2280
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2281<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2282
2283<dl>
2284 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2285 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2286 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2287
2288 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2289 <dd>Standard integers (such as '4') are constants of
2290 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2291 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292
2293 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2294 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2295 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2296 notation (see below). The assembler requires the exact decimal value of a
2297 floating-point constant. For example, the assembler accepts 1.25 but
2298 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2299 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2300
2301 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2302 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2304</dl>
2305
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2306<p>The one non-intuitive notation for constants is the hexadecimal form of
2307 floating point constants. For example, the form '<tt>double
2308 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2309 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2310 constants are required (and the only time that they are generated by the
2311 disassembler) is when a floating point constant must be emitted but it cannot
2312 be represented as a decimal floating point number in a reasonable number of
2313 digits. For example, NaN's, infinities, and other special values are
2314 represented in their IEEE hexadecimal format so that assembly and disassembly
2315 do not cause any bits to change in the constants.</p>
2316
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2317<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2318 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2319 representation for double); half and float values must, however, be exactly
2320 representable as IEE754 half and single precision, respectively.
2321 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2322 for long double, and there are three forms of long double. The 80-bit format
2323 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2324 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2325 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2326 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2327 currently supported target uses this format. Long doubles will only work if
Tobias Grosser057beb82012-05-24 15:59:06 +0000[diff] [blame]2328 they match the long double format on your target. The IEEE 16-bit format
2329 (half precision) is represented by <tt>0xH</tt> followed by 4 hexadecimal
2330 digits. All hexadecimal formats are big-endian (sign bit at the left).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2331
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2332<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2333</div>
2334
2335<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2336<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2337<a name="aggregateconstants"></a> <!-- old anchor -->
2338<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2339</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2340
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2341<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2342
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2343<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2344 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2345
2346<dl>
2347 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2348 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2349 type definitions (a comma separated list of elements, surrounded by braces
2350 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2351 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2352 Structure constants must have <a href="#t_struct">structure type</a>, and
2353 the number and types of elements must match those specified by the
2354 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2355
2356 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2357 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2358 definitions (a comma separated list of elements, surrounded by square
2359 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2360 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2361 the number and types of elements must match those specified by the
2362 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2363
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2364 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2365 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2366 definitions (a comma separated list of elements, surrounded by
2367 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2368 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2369 have <a href="#t_vector">vector type</a>, and the number and types of
2370 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2371
2372 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2373 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2374 value to zero of <em>any</em> type, including scalar and
2375 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2376 This is often used to avoid having to print large zero initializers
2377 (e.g. for large arrays) and is always exactly equivalent to using explicit
2378 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2379
2380 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2381 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2382 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2383 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2384 be interpreted as part of the instruction stream, metadata is a place to
2385 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2386</dl>
2387
2388</div>
2389
2390<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2391<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2392 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2393</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2394
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2395<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2396
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2397<p>The addresses of <a href="#globalvars">global variables</a>
2398 and <a href="#functionstructure">functions</a> are always implicitly valid
2399 (link-time) constants. These constants are explicitly referenced when
2400 the <a href="#identifiers">identifier for the global</a> is used and always
2401 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2402 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2403
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2404<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2405@X = global i32 17
2406@Y = global i32 42
2407@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2408</pre>
2409
2410</div>
2411
2412<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2413<h3>
2414 <a name="undefvalues">Undefined Values</a>
2415</h3>
2416
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2417<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2418
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2419<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]2420 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2421 Undefined values may be of any type (other than '<tt>label</tt>'
2422 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2423
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2424<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2425 program is well defined no matter what value is used. This gives the
2426 compiler more freedom to optimize. Here are some examples of (potentially
2427 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2428
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2429
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2430<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2431 %A = add %X, undef
2432 %B = sub %X, undef
2433 %C = xor %X, undef
2434Safe:
2435 %A = undef
2436 %B = undef
2437 %C = undef
2438</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2439
2440<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]2441 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]2442
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2443<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2444 %A = or %X, undef
2445 %B = and %X, undef
2446Safe:
2447 %A = -1
2448 %B = 0
2449Unsafe:
2450 %A = undef
2451 %B = undef
2452</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2453
2454<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2455 For example, if <tt>%X</tt> has a zero bit, then the output of the
2456 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2457 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2458 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2459 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2460 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2461 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2462 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2463
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2464<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2465 %A = select undef, %X, %Y
2466 %B = select undef, 42, %Y
2467 %C = select %X, %Y, undef
2468Safe:
2469 %A = %X (or %Y)
2470 %B = 42 (or %Y)
2471 %C = %Y
2472Unsafe:
2473 %A = undef
2474 %B = undef
2475 %C = undef
2476</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2477
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2478<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2479 branch) conditions can go <em>either way</em>, but they have to come from one
2480 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2481 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2482 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2483 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2484 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2485 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2486
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2487<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2488 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2489
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2490 %B = undef
2491 %C = xor %B, %B
2492
2493 %D = undef
2494 %E = icmp lt %D, 4
2495 %F = icmp gte %D, 4
2496
2497Safe:
2498 %A = undef
2499 %B = undef
2500 %C = undef
2501 %D = undef
2502 %E = undef
2503 %F = undef
2504</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2505
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2506<p>This example points out that two '<tt>undef</tt>' operands are not
2507 necessarily the same. This can be surprising to people (and also matches C
2508 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2509 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2510 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2511 its value over its "live range". This is true because the variable doesn't
2512 actually <em>have a live range</em>. Instead, the value is logically read
2513 from arbitrary registers that happen to be around when needed, so the value
2514 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2515 need to have the same semantics or the core LLVM "replace all uses with"
2516 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2517
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2518<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2519 %A = fdiv undef, %X
2520 %B = fdiv %X, undef
2521Safe:
2522 %A = undef
2523b: unreachable
2524</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2525
2526<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2527 value</em> and <em>undefined behavior</em>. An undefined value (like
2528 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2529 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2530 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2531 defined on SNaN's. However, in the second example, we can make a more
2532 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2533 arbitrary value, we are allowed to assume that it could be zero. Since a
2534 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2535 the operation does not execute at all. This allows us to delete the divide and
2536 all code after it. Because the undefined operation "can't happen", the
2537 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2538
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2539<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2540a: store undef -> %X
2541b: store %X -> undef
2542Safe:
2543a: &lt;deleted&gt;
2544b: unreachable
2545</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2546
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2547<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2548 undefined value can be assumed to not have any effect; we can assume that the
2549 value is overwritten with bits that happen to match what was already there.
2550 However, a store <em>to</em> an undefined location could clobber arbitrary
2551 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2552
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2553</div>
2554
2555<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2556<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2557 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2558</h3>
2559
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2560<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2561
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2562<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2563 they also represent the fact that an instruction or constant expression which
2564 cannot evoke side effects has nevertheless detected a condition which results
2565 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2566
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2567<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]2568 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2569 <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]2570
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2571<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2572
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2573<ul>
2574<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2575 their operands.</li>
2576
2577<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2578 to their dynamic predecessor basic block.</li>
2579
2580<li>Function arguments depend on the corresponding actual argument values in
2581 the dynamic callers of their functions.</li>
2582
2583<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2584 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2585 control back to them.</li>
2586
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2587<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]2588 <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]2589 or exception-throwing call instructions that dynamically transfer control
2590 back to them.</li>
2591
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2592<li>Non-volatile loads and stores depend on the most recent stores to all of the
2593 referenced memory addresses, following the order in the IR
2594 (including loads and stores implied by intrinsics such as
2595 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2596
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2597<!-- TODO: In the case of multiple threads, this only applies if the store
2598 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2599
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2600<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2601
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2602<li>An instruction with externally visible side effects depends on the most
2603 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2604 the order in the IR. (This includes
2605 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2606
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2607<li>An instruction <i>control-depends</i> on a
2608 <a href="#terminators">terminator instruction</a>
2609 if the terminator instruction has multiple successors and the instruction
2610 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2611 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2612
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2613<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2614 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2615 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2616 successor.</li>
2617
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2618<li>Dependence is transitive.</li>
2619
2620</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2621
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2622<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2623 with the additional affect that any instruction which has a <i>dependence</i>
2624 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2625
2626<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2627
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2628<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2629entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2630 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2631 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2632 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2633 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2634
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2635 store i32 %poison, i32* @g ; Poison value stored to memory.
2636 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2637
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2638 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2639
2640 %narrowaddr = bitcast i32* @g to i16*
2641 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2642 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2643 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2644
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2645 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2646 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2647
2648true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2649 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2650 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2651 br label %end
2652
2653end:
2654 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2655 ; Both edges into this PHI are
2656 ; control-dependent on %cmp, so this
2657 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2658
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2659 store volatile i32 0, i32* @g ; This would depend on the store in %true
2660 ; if %cmp is true, or the store in %entry
2661 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2662
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2663 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2664 ; The same branch again, but this time the
2665 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2666
2667second_true:
2668 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2669 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2670
2671second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2672 store volatile i32 0, i32* @g ; This time, the instruction always depends
2673 ; on the store in %end. Also, it is
2674 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2675 ; well-defined (ignoring earlier undefined
2676 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2677</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2678
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2679</div>
2680
2681<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2682<h3>
2683 <a name="blockaddress">Addresses of Basic Blocks</a>
2684</h3>
2685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2686<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2687
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2688<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2689
2690<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2691 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2692 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2693
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2694<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2695 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2696 comparisons against null. Pointer equality tests between labels addresses
2697 results in undefined behavior &mdash; though, again, comparison against null
2698 is ok, and no label is equal to the null pointer. This may be passed around
2699 as an opaque pointer sized value as long as the bits are not inspected. This
2700 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2701 long as the original value is reconstituted before the <tt>indirectbr</tt>
2702 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2703
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2704<p>Finally, some targets may provide defined semantics when using the value as
2705 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2706
2707</div>
2708
2709
2710<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2711<h3>
2712 <a name="constantexprs">Constant Expressions</a>
2713</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2714
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2715<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2716
2717<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2718 to be used as constants. Constant expressions may be of
2719 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2720 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2721 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2722
2723<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2724 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2725 <dd>Truncate a constant to another type. The bit size of CST must be larger
2726 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2727
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2729 <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]2730 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2731
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2732 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2733 <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]2734 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2735
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2736 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2737 <dd>Truncate a floating point constant to another floating point type. The
2738 size of CST must be larger than the size of TYPE. Both types must be
2739 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2740
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2741 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2742 <dd>Floating point extend a constant to another type. The size of CST must be
2743 smaller or equal to the size of TYPE. Both types must be floating
2744 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2745
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2746 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2747 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2748 constant. TYPE must be a scalar or vector integer type. CST must be of
2749 scalar or vector floating point type. Both CST and TYPE must be scalars,
2750 or vectors of the same number of elements. If the value won't fit in the
2751 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2752
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2753 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2754 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2755 constant. TYPE must be a scalar or vector integer type. CST must be of
2756 scalar or vector floating point type. Both CST and TYPE must be scalars,
2757 or vectors of the same number of elements. If the value won't fit in the
2758 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2759
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2760 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2761 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2762 constant. TYPE must be a scalar or vector floating point type. CST must be
2763 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2764 vectors of the same number of elements. If the value won't fit in the
2765 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2766
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2767 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2768 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2769 constant. TYPE must be a scalar or vector floating point type. CST must be
2770 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2771 vectors of the same number of elements. If the value won't fit in the
2772 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2773
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2774 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2775 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2776 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2777 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2778 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2779
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2780 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2781 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2782 type. CST must be of integer type. The CST value is zero extended,
2783 truncated, or unchanged to make it fit in a pointer size. This one is
2784 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2785
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2786 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2787 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2788 are the same as those for the <a href="#i_bitcast">bitcast
2789 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2790
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2791 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2792 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2793 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2794 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2795 instruction, the index list may have zero or more indexes, which are
2796 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2797
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2798 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2799 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2800
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2801 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2802 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2803
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2804 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2805 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2806
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2807 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2808 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2809 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2810
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2811 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2812 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2813 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2814
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2815 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2816 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2817 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2818
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2819 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2820 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2821 constants. The index list is interpreted in a similar manner as indices in
2822 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2823 index value must be specified.</dd>
2824
2825 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2826 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2827 constants. The index list is interpreted in a similar manner as indices in
2828 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2829 index value must be specified.</dd>
2830
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2831 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2833 be any of the <a href="#binaryops">binary</a>
2834 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2835 on operands are the same as those for the corresponding instruction
2836 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2837</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2838
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2839</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2840
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2841</div>
2842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2843<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2844<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2845<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2846<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2847<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2848<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2849<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2850</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2852<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2855 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2856 a special value. This value represents the inline assembler as a string
2857 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2858 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2859 expression has side effects, and a flag indicating whether the function
2860 containing the asm needs to align its stack conservatively. An example
2861 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2862
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2863<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2864i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2865</pre>
2866
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2867<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2868 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2869 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2870
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2871<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2872%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]2873</pre>
2874
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2875<p>Inline asms with side effects not visible in the constraint list must be
2876 marked as having side effects. This is done through the use of the
2877 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2878
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2879<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2880call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2881</pre>
2882
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2883<p>In some cases inline asms will contain code that will not work unless the
2884 stack is aligned in some way, such as calls or SSE instructions on x86,
2885 yet will not contain code that does that alignment within the asm.
2886 The compiler should make conservative assumptions about what the asm might
2887 contain and should generate its usual stack alignment code in the prologue
2888 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2889
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2890<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2891call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2892</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2893
2894<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2895 first.</p>
2896
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2897<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2898<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2899 documented here. Constraints on what can be done (e.g. duplication, moving,
2900 etc need to be documented). This is probably best done by reference to
2901 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2902 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2903
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2904<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2905<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2906 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2907</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2908
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2909<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2910
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2911<p>The call instructions that wrap inline asm nodes may have a
2912 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2913 integers. If present, the code generator will use the integer as the
2914 location cookie value when report errors through the <tt>LLVMContext</tt>
2915 error reporting mechanisms. This allows a front-end to correlate backend
2916 errors that occur with inline asm back to the source code that produced it.
2917 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2918
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2919<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2920call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2921...
2922!42 = !{ i32 1234567 }
2923</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2924
2925<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]2926 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2927 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]2928
2929</div>
2930
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2931</div>
2932
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2933<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2934<h3>
2935 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2936</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2937
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2938<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2939
2940<p>LLVM IR allows metadata to be attached to instructions in the program that
2941 can convey extra information about the code to the optimizers and code
2942 generator. One example application of metadata is source-level debug
2943 information. There are two metadata primitives: strings and nodes. All
2944 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2945 preceding exclamation point ('<tt>!</tt>').</p>
2946
2947<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2948 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2949 "<tt>xx</tt>" is the two digit hex code. For example:
2950 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2951
2952<p>Metadata nodes are represented with notation similar to structure constants
2953 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2954 exclamation point). Metadata nodes can have any values as their operand. For
2955 example:</p>
2956
2957<div class="doc_code">
2958<pre>
2959!{ metadata !"test\00", i32 10}
2960</pre>
2961</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2962
2963<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2964 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2965 example:</p>
2966
2967<div class="doc_code">
2968<pre>
2969!foo = metadata !{!4, !3}
2970</pre>
2971</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2972
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2973<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2974 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2975
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2976<div class="doc_code">
2977<pre>
2978call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2979</pre>
2980</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2981
2982<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2983 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2984 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2985
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2986<div class="doc_code">
2987<pre>
2988%indvar.next = add i64 %indvar, 1, !dbg !21
2989</pre>
2990</div>
2991
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2992<p>More information about specific metadata nodes recognized by the optimizers
2993 and code generator is found below.</p>
2994
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2995<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2996<h4>
2997 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2998</h4>
2999
3000<div>
3001
3002<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
3003 suitable for doing TBAA. Instead, metadata is added to the IR to describe
3004 a type system of a higher level language. This can be used to implement
3005 typical C/C++ TBAA, but it can also be used to implement custom alias
3006 analysis behavior for other languages.</p>
3007
3008<p>The current metadata format is very simple. TBAA metadata nodes have up to
3009 three fields, e.g.:</p>
3010
3011<div class="doc_code">
3012<pre>
3013!0 = metadata !{ metadata !"an example type tree" }
3014!1 = metadata !{ metadata !"int", metadata !0 }
3015!2 = metadata !{ metadata !"float", metadata !0 }
3016!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
3017</pre>
3018</div>
3019
3020<p>The first field is an identity field. It can be any value, usually
3021 a metadata string, which uniquely identifies the type. The most important
3022 name in the tree is the name of the root node. Two trees with
3023 different root node names are entirely disjoint, even if they
3024 have leaves with common names.</p>
3025
3026<p>The second field identifies the type's parent node in the tree, or
3027 is null or omitted for a root node. A type is considered to alias
3028 all of its descendants and all of its ancestors in the tree. Also,
3029 a type is considered to alias all types in other trees, so that
3030 bitcode produced from multiple front-ends is handled conservatively.</p>
3031
3032<p>If the third field is present, it's an integer which if equal to 1
3033 indicates that the type is "constant" (meaning
3034 <tt>pointsToConstantMemory</tt> should return true; see
3035 <a href="AliasAnalysis.html#OtherItfs">other useful
3036 <tt>AliasAnalysis</tt> methods</a>).</p>
3037
3038</div>
3039
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]3040<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3041<h4>
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3042 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3043</h4>
3044
3045<div>
3046
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3047<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3048 type. It can be used to express the maximum acceptable error in the result of
3049 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3050 more efficient but less accurate method of computing it. ULP is defined as
3051 follows:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3052
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3053<blockquote>
3054
3055<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3056 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3057 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3058 distance between the two non-equal finite floating-point numbers nearest
3059 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3060
3061</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3062
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3063<p>The metadata node shall consist of a single positive floating point number
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3064 representing the maximum relative error, for example:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3065
3066<div class="doc_code">
3067<pre>
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3068!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3069</pre>
3070</div>
3071
NAKAMURA Takumi9c55f592012-03-27 11:25:16 +0000[diff] [blame]3072</div>
3073
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3074<!-- _______________________________________________________________________ -->
3075<h4>
3076 <a name="range">'<tt>range</tt>' Metadata</a>
3077</h4>
3078
3079<div>
3080<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3081 expresses the possible ranges the loaded value is in. The ranges are
3082 represented with a flattened list of integers. The loaded value is known to
3083 be in the union of the ranges defined by each consecutive pair. Each pair
3084 has the following properties:</p>
3085<ul>
3086 <li>The type must match the type loaded by the instruction.</li>
3087 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3088 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3089 <li>The range is allowed to wrap.</li>
3090 <li>The range should not represent the full or empty set. That is,
3091 <tt>a!=b</tt>. </li>
3092</ul>
Rafael Espindolaa1b95f52012-05-31 16:04:26 +0000[diff] [blame]3093<p> In addition, the pairs must be in signed order of the lower bound and
3094 they must be non-contiguous.</p>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3095
3096<p>Examples:</p>
3097<div class="doc_code">
3098<pre>
3099 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3100 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3101 %c = load i8* %z, align 1, !range !2 ; Can only be 0, 1, 3, 4 or 5
Rafael Espindolac49b29e2012-05-31 13:45:46 +0000[diff] [blame]3102 %d = load i8* %z, align 1, !range !3 ; Can only be -2, -1, 3, 4 or 5
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3103...
3104!0 = metadata !{ i8 0, i8 2 }
3105!1 = metadata !{ i8 255, i8 2 }
3106!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
Rafael Espindolac49b29e2012-05-31 13:45:46 +0000[diff] [blame]3107!3 = metadata !{ i8 -2, i8 0, i8 3, i8 6 }
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3108</pre>
3109</div>
3110</div>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3111</div>
3112
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3113</div>
3114
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3115<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3116<h2>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3117 <a name="module_flags">Module Flags Metadata</a>
3118</h2>
3119<!-- *********************************************************************** -->
3120
3121<div>
3122
3123<p>Information about the module as a whole is difficult to convey to LLVM's
3124 subsystems. The LLVM IR isn't sufficient to transmit this
3125 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3126 facilitate this. These flags are in the form of key / value pairs &mdash;
3127 much like a dictionary &mdash; making it easy for any subsystem who cares
3128 about a flag to look it up.</p>
3129
3130<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3131 triplets. Each triplet has the following form:</p>
3132
3133<ul>
3134 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3135 when two (or more) modules are merged together, and it encounters two (or
3136 more) metadata with the same ID. The supported behaviors are described
3137 below.</li>
3138
3139 <li>The second element is a metadata string that is a unique ID for the
3140 metadata. How each ID is interpreted is documented below.</li>
3141
3142 <li>The third element is the value of the flag.</li>
3143</ul>
3144
3145<p>When two (or more) modules are merged together, the resulting
3146 <tt>llvm.module.flags</tt> metadata is the union of the
3147 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3148 with the <i>Override</i> behavior, which may override another flag's value
3149 (see below).</p>
3150
3151<p>The following behaviors are supported:</p>
3152
3153<table border="1" cellspacing="0" cellpadding="4">
3154 <tbody>
3155 <tr>
3156 <th>Value</th>
3157 <th>Behavior</th>
3158 </tr>
3159 <tr>
3160 <td>1</td>
3161 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3162 <dl>
3163 <dt><b>Error</b></dt>
3164 <dd>Emits an error if two values disagree. It is an error to have an ID
3165 with both an Error and a Warning behavior.</dd>
3166 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3167 </td>
3168 </tr>
3169 <tr>
3170 <td>2</td>
3171 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3172 <dl>
3173 <dt><b>Warning</b></dt>
3174 <dd>Emits a warning if two values disagree.</dd>
3175 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3176 </td>
3177 </tr>
3178 <tr>
3179 <td>3</td>
3180 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3181 <dl>
3182 <dt><b>Require</b></dt>
3183 <dd>Emits an error when the specified value is not present or doesn't
3184 have the specified value. It is an error for two (or more)
3185 <tt>llvm.module.flags</tt> with the same ID to have the Require
3186 behavior but different values. There may be multiple Require flags
3187 per ID.</dd>
3188 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3189 </td>
3190 </tr>
3191 <tr>
3192 <td>4</td>
3193 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3194 <dl>
3195 <dt><b>Override</b></dt>
3196 <dd>Uses the specified value if the two values disagree. It is an
3197 error for two (or more) <tt>llvm.module.flags</tt> with the same
3198 ID to have the Override behavior but different values.</dd>
3199 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3200 </td>
3201 </tr>
3202 </tbody>
3203</table>
3204
3205<p>An example of module flags:</p>
3206
3207<pre class="doc_code">
3208!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3209!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3210!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3211!3 = metadata !{ i32 3, metadata !"qux",
3212 metadata !{
3213 metadata !"foo", i32 1
3214 }
3215}
3216!llvm.module.flags = !{ !0, !1, !2, !3 }
3217</pre>
3218
3219<ul>
3220 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3221 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3222 error if their values are not equal.</p></li>
3223
3224 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3225 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3226 value '37' if their values are not equal.</p></li>
3227
3228 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3229 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3230 warning if their values are not equal.</p></li>
3231
3232 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3233
3234<pre class="doc_code">
3235metadata !{ metadata !"foo", i32 1 }
3236</pre>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3237
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3238 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3239 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3240 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3241 the same value or an error will be issued.</p></li>
3242</ul>
3243
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3244
3245<!-- ======================================================================= -->
3246<h3>
3247<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3248</h3>
3249
3250<div>
3251
3252<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3253 in a special section called "image info". The metadata consists of a version
3254 number and a bitmask specifying what types of garbage collection are
3255 supported (if any) by the file. If two or more modules are linked together
3256 their garbage collection metadata needs to be merged rather than appended
3257 together.</p>
3258
3259<p>The Objective-C garbage collection module flags metadata consists of the
3260 following key-value pairs:</p>
3261
3262<table border="1" cellspacing="0" cellpadding="4">
Bill Wendlingb3ef2232012-03-06 09:23:25 +0000[diff] [blame]3263 <col width="30%">
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3264 <tbody>
3265 <tr>
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3266 <th>Key</th>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3267 <th>Value</th>
3268 </tr>
3269 <tr>
3270 <td><tt>Objective-C&nbsp;Version</tt></td>
3271 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3272 version. Valid values are 1 and 2.</td>
3273 </tr>
3274 <tr>
3275 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3276 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3277 section. Currently always 0.</td>
3278 </tr>
3279 <tr>
3280 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3281 <td align="left"><b>[Required]</b> &mdash; The section to place the
3282 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3283 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3284 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3285 </tr>
3286 <tr>
3287 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3288 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3289 collection is supported or not. Valid values are 0, for no garbage
3290 collection, and 2, for garbage collection supported.</td>
3291 </tr>
3292 <tr>
3293 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3294 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3295 collection is supported. If present, its value must be 6. This flag
3296 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3297 value 2.</td>
3298 </tr>
3299 </tbody>
3300</table>
3301
3302<p>Some important flag interactions:</p>
3303
3304<ul>
3305 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3306 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3307 2, then the resulting module has the <tt>Objective-C Garbage
3308 Collection</tt> flag set to 0.</li>
3309
3310 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3311 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3312</ul>
3313
3314</div>
3315
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3316</div>
3317
3318<!-- *********************************************************************** -->
3319<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3320 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3321</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3322<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3323<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3324<p>LLVM has a number of "magic" global variables that contain data that affect
3325code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3326of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3327section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3328by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3329
3330<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3331<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3332<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3333</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3334
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3335<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3336
3337<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3338href="#linkage_appending">appending linkage</a>. This array contains a list of
3339pointers to global variables and functions which may optionally have a pointer
3340cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3341
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3342<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3343<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3344@X = global i8 4
3345@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3346
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3347@llvm.used = appending global [2 x i8*] [
3348 i8* @X,
3349 i8* bitcast (i32* @Y to i8*)
3350], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3351</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3352</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3353
3354<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]3355 compiler, assembler, and linker are required to treat the symbol as if there
3356 is a reference to the global that it cannot see. For example, if a variable
3357 has internal linkage and no references other than that from
3358 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3359 represent references from inline asms and other things the compiler cannot
3360 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3361
3362<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]3363 object file to prevent the assembler and linker from molesting the
3364 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3365
3366</div>
3367
3368<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3369<h3>
3370 <a name="intg_compiler_used">
3371 The '<tt>llvm.compiler.used</tt>' Global Variable
3372 </a>
3373</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3374
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3375<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3376
3377<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3378 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3379 touching the symbol. On targets that support it, this allows an intelligent
3380 linker to optimize references to the symbol without being impeded as it would
3381 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3382
3383<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]3384 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3385
3386</div>
3387
3388<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3389<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3390<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3391</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3392
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3393<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3394
3395<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3396<pre>
3397%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3398@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3399</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3400</div>
3401
3402<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3403 functions and associated priorities. The functions referenced by this array
3404 will be called in ascending order of priority (i.e. lowest first) when the
3405 module is loaded. The order of functions with the same priority is not
3406 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3407
3408</div>
3409
3410<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3411<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3412<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3413</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3414
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3415<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3416
3417<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3418<pre>
3419%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3420@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3421</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3422</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3423
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3424<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3425 and associated priorities. The functions referenced by this array will be
3426 called in descending order of priority (i.e. highest first) when the module
3427 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3428
3429</div>
3430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3431</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3432
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3433<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3434<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3435<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3436
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3437<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3438
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439<p>The LLVM instruction set consists of several different classifications of
3440 instructions: <a href="#terminators">terminator
3441 instructions</a>, <a href="#binaryops">binary instructions</a>,
3442 <a href="#bitwiseops">bitwise binary instructions</a>,
3443 <a href="#memoryops">memory instructions</a>, and
3444 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3445
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3446<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3447<h3>
3448 <a name="terminators">Terminator Instructions</a>
3449</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3450
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3451<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3453<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3454 in a program ends with a "Terminator" instruction, which indicates which
3455 block should be executed after the current block is finished. These
3456 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3457 control flow, not values (the one exception being the
3458 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3459
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3460<p>The terminator instructions are:
3461 '<a href="#i_ret"><tt>ret</tt></a>',
3462 '<a href="#i_br"><tt>br</tt></a>',
3463 '<a href="#i_switch"><tt>switch</tt></a>',
3464 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3465 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3466 '<a href="#i_resume"><tt>resume</tt></a>', and
3467 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3468
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3469<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3470<h4>
3471 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3472</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3474<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3475
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3476<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3477<pre>
3478 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]3479 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3480</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3481
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3482<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3484 a value) from a function back to the caller.</p>
3485
3486<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3487 value and then causes control flow, and one that just causes control flow to
3488 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3490<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3492 return value. The type of the return value must be a
3493 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3494
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3496 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3497 value or a return value with a type that does not match its type, or if it
3498 has a void return type and contains a '<tt>ret</tt>' instruction with a
3499 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3500
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3503 the calling function's context. If the caller is a
3504 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3505 instruction after the call. If the caller was an
3506 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3507 the beginning of the "normal" destination block. If the instruction returns
3508 a value, that value shall set the call or invoke instruction's return
3509 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3510
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3511<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3512<pre>
3513 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3514 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3515 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]3516</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3517
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3518</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3519<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3520<h4>
3521 <a name="i_br">'<tt>br</tt>' Instruction</a>
3522</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3524<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3526<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3527<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3528 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3529 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3530</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3532<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3534 different basic block in the current function. There are two forms of this
3535 instruction, corresponding to a conditional branch and an unconditional
3536 branch.</p>
3537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3538<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3540 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3541 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3542 target.</p>
3543
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3544<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3545<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3546 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3547 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3548 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3549
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3550<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3551<pre>
3552Test:
3553 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3554 br i1 %cond, label %IfEqual, label %IfUnequal
3555IfEqual:
3556 <a href="#i_ret">ret</a> i32 1
3557IfUnequal:
3558 <a href="#i_ret">ret</a> i32 0
3559</pre>
3560
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3561</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3564<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3565 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3566</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3567
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3568<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3571<pre>
3572 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3573</pre>
3574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3575<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3576<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]3577 several different places. It is a generalization of the '<tt>br</tt>'
3578 instruction, allowing a branch to occur to one of many possible
3579 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3580
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3581<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3582<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3584 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3585 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3587<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3588<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3589 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3590 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3591 transferred to the corresponding destination; otherwise, control flow is
3592 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3593
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3594<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3595<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3596 <tt>switch</tt> instruction, this instruction may be code generated in
3597 different ways. For example, it could be generated as a series of chained
3598 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3599
3600<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3601<pre>
3602 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3603 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3604 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3605
3606 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3607 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3608
3609 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3610 switch i32 %val, label %otherwise [ i32 0, label %onzero
3611 i32 1, label %onone
3612 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3613</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3615</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3616
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3617
3618<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3619<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3620 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3621</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3622
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3623<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3624
3625<h5>Syntax:</h5>
3626<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3627 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]3628</pre>
3629
3630<h5>Overview:</h5>
3631
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3632<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3633 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3634 "<tt>address</tt>". Address must be derived from a <a
3635 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3636
3637<h5>Arguments:</h5>
3638
3639<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3640 rest of the arguments indicate the full set of possible destinations that the
3641 address may point to. Blocks are allowed to occur multiple times in the
3642 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3643
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3644<p>This destination list is required so that dataflow analysis has an accurate
3645 understanding of the CFG.</p>
3646
3647<h5>Semantics:</h5>
3648
3649<p>Control transfers to the block specified in the address argument. All
3650 possible destination blocks must be listed in the label list, otherwise this
3651 instruction has undefined behavior. This implies that jumps to labels
3652 defined in other functions have undefined behavior as well.</p>
3653
3654<h5>Implementation:</h5>
3655
3656<p>This is typically implemented with a jump through a register.</p>
3657
3658<h5>Example:</h5>
3659<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3660 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3661</pre>
3662
3663</div>
3664
3665
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3666<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3667<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3668 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3669</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3670
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3671<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3672
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3673<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3674<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3675 &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]3676 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3677</pre>
3678
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3679<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3680<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3681 function, with the possibility of control flow transfer to either the
3682 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3683 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3684 control flow will return to the "normal" label. If the callee (or any
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3685 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3686 instruction or other exception handling mechanism, control is interrupted and
3687 continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3688
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3689<p>The '<tt>exception</tt>' label is a
3690 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3691 exception. As such, '<tt>exception</tt>' label is required to have the
3692 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3693 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3694 happens, as its first non-PHI instruction. The restrictions on the
3695 "<tt>landingpad</tt>" instruction's tightly couples it to the
3696 "<tt>invoke</tt>" instruction, so that the important information contained
3697 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3698 code motion.</p>
3699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3700<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3701<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3703<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3705 convention</a> the call should use. If none is specified, the call
3706 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3707
3708 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3710 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3711
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3712 <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]3713 function value being invoked. In most cases, this is a direct function
3714 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3715 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3716
3717 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3718 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3719
3720 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3721 signature argument types and parameter attributes. All arguments must be
3722 of <a href="#t_firstclass">first class</a> type. If the function
3723 signature indicates the function accepts a variable number of arguments,
3724 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3725
3726 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3727 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3728
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3729 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3730 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3731 handling mechanism.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3732
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3733 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3734 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3735 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3736</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3738<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3739<p>This instruction is designed to operate as a standard
3740 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3741 primary difference is that it establishes an association with a label, which
3742 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3743
3744<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3745 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3746 exception. Additionally, this is important for implementation of
3747 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3749<p>For the purposes of the SSA form, the definition of the value returned by the
3750 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3751 block to the "normal" label. If the callee unwinds then no return value is
3752 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3754<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3755<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3756 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3757 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3758 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3759 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3760</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3761
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3763
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3764 <!-- _______________________________________________________________________ -->
3765
3766<h4>
3767 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3768</h4>
3769
3770<div>
3771
3772<h5>Syntax:</h5>
3773<pre>
3774 resume &lt;type&gt; &lt;value&gt;
3775</pre>
3776
3777<h5>Overview:</h5>
3778<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3779 successors.</p>
3780
3781<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3782<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3783 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3784 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
3787<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3788 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3789 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3790
3791<h5>Example:</h5>
3792<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3793 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3794</pre>
3795
3796</div>
3797
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3798<!-- _______________________________________________________________________ -->
3799
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3800<h4>
3801 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3802</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3803
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3804<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3805
3806<h5>Syntax:</h5>
3807<pre>
3808 unreachable
3809</pre>
3810
3811<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3812<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3813 instruction is used to inform the optimizer that a particular portion of the
3814 code is not reachable. This can be used to indicate that the code after a
3815 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3816
3817<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3818<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3819
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3820</div>
3821
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3822</div>
3823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3824<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3825<h3>
3826 <a name="binaryops">Binary Operations</a>
3827</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3828
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3829<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3830
3831<p>Binary operators are used to do most of the computation in a program. They
3832 require two operands of the same type, execute an operation on them, and
3833 produce a single value. The operands might represent multiple data, as is
3834 the case with the <a href="#t_vector">vector</a> data type. The result value
3835 has the same type as its operands.</p>
3836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3837<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3839<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3840<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3841 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3842</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3843
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3844<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3845
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3846<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3847<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3848 &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]3849 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3850 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3851 &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]3852</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3854<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3855<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3857<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858<p>The two arguments to the '<tt>add</tt>' instruction must
3859 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3860 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3862<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3863<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865<p>If the sum has unsigned overflow, the result returned is the mathematical
3866 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]3867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<p>Because LLVM integers use a two's complement representation, this instruction
3869 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3870
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3871<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3872 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3873 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3874 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3875 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3878<pre>
3879 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3880</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3881
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3882</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3885<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3886 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3887</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3888
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3889<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3890
3891<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3892<pre>
3893 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3894</pre>
3895
3896<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3897<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3898
3899<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3900<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3901 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3902 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3903
3904<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3905<p>The value produced is the floating point sum of the two operands.</p>
3906
3907<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3908<pre>
3909 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3910</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3912</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3914<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3915<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3916 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3917</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3918
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3919<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3922<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3923 &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]3924 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3925 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3926 &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]3927</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3929<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3930<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3932
3933<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3934 '<tt>neg</tt>' instruction present in most other intermediate
3935 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3937<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3938<p>The two arguments to the '<tt>sub</tt>' instruction must
3939 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3940 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3941
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3942<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3943<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3944
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3945<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3946 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3947 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3948
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949<p>Because LLVM integers use a two's complement representation, this instruction
3950 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3951
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3952<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3953 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3954 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3955 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3956 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3957
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3958<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3959<pre>
3960 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3961 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3962</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3963
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3964</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3965
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3966<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3967<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3968 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3969</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3971<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3972
3973<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3974<pre>
3975 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3976</pre>
3977
3978<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3979<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3980 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3981
3982<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3983 '<tt>fneg</tt>' instruction present in most other intermediate
3984 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3985
3986<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3987<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3989 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3990
3991<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3992<p>The value produced is the floating point difference of the two operands.</p>
3993
3994<h5>Example:</h5>
3995<pre>
3996 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3997 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3998</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3999
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4000</div>
4001
4002<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4003<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4004 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4005</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4006
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4007<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4008
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4009<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4011 &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]4012 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4013 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4014 &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]4015</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4017<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4018<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4019
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4020<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021<p>The two arguments to the '<tt>mul</tt>' instruction must
4022 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4023 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4024
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4025<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4026<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4027
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4028<p>If the result of the multiplication has unsigned overflow, the result
4029 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
4030 width of the result.</p>
4031
4032<p>Because LLVM integers use a two's complement representation, and the result
4033 is the same width as the operands, this instruction returns the correct
4034 result for both signed and unsigned integers. If a full product
4035 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
4036 be sign-extended or zero-extended as appropriate to the width of the full
4037 product.</p>
4038
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4039<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4040 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4041 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4042 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]4043 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4045<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046<pre>
4047 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4048</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4049
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4050</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4051
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4052<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4053<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4054 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4055</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4056
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4057<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4058
4059<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4060<pre>
4061 &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]4062</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4064<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4066
4067<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4068<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4069 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4070 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4073<p>The value produced is the floating point product of the two operands.</p>
4074
4075<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076<pre>
4077 &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]4078</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4079
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4080</div>
4081
4082<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4083<h4>
4084 <a name="i_udiv">'<tt>udiv</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>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4090<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4091 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4092 &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]4093</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +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>udiv</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>udiv</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>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4104<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4105
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4106<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4107 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4108
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4109<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4110
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4111<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4112 <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]4113 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4114
4115
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4116<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4117<pre>
4118 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4119</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4120
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4121</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4122
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4123<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4124<h4>
4125 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4126</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4127
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4128<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4130<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4131<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4132 &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]4133 &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]4134</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4135
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4136<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4137<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4138
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4139<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4140<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4141 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4142 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4143
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4144<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4145<p>The value produced is the signed integer quotient of the two operands rounded
4146 towards zero.</p>
4147
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4148<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4150
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4151<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4152 undefined behavior; this is a rare case, but can occur, for example, by doing
4153 a 32-bit division of -2147483648 by -1.</p>
4154
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]4155<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4156 <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]4157 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4158
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4159<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4160<pre>
4161 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4162</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4164</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4166<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4167<h4>
4168 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4169</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4170
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4171<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4172
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4173<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4174<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4175 &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]4176</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4177
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178<h5>Overview:</h5>
4179<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4180
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4181<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4182<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4183 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4184 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4185
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4186<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4187<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4188
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4189<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4190<pre>
4191 &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]4192</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4193
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4194</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4195
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4196<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4197<h4>
4198 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4199</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4200
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4201<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4202
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4203<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4204<pre>
4205 &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]4206</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4208<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4209<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4210 division of its two arguments.</p>
4211
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4212<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4213<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4215 values. Both arguments must have identical types.</p>
4216
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4217<h5>Semantics:</h5>
4218<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219 This instruction always performs an unsigned division to get the
4220 remainder.</p>
4221
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4222<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4223 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4224
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4225<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4226
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4227<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228<pre>
4229 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4230</pre>
4231
4232</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4233
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4234<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4235<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4236 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4237</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4238
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4239<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4240
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4241<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4242<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4243 &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]4244</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4246<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4247<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4248 division of its two operands. This instruction can also take
4249 <a href="#t_vector">vector</a> versions of the values in which case the
4250 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]4251
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4252<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4253<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4255 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4256
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4257<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4258<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4259 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4260 <i>modulo</i> operator (where the result is either zero or has the same sign
4261 as the divisor, <tt>op2</tt>) of a value.
4262 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4263 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4264 Math Forum</a>. For a table of how this is implemented in various languages,
4265 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4266 Wikipedia: modulo operation</a>.</p>
4267
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4268<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4269 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4270
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4271<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4272 Overflow also leads to undefined behavior; this is a rare case, but can
4273 occur, for example, by taking the remainder of a 32-bit division of
4274 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4275 lets srem be implemented using instructions that return both the result of
4276 the division and the remainder.)</p>
4277
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4278<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4279<pre>
4280 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4281</pre>
4282
4283</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4285<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4286<h4>
4287 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4288</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4289
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4290<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4291
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4292<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4293<pre>
4294 &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]4295</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4297<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4298<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4299 its two operands.</p>
4300
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4301<h5>Arguments:</h5>
4302<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4304 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4305
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4306<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4307<p>This instruction returns the <i>remainder</i> of a division. The remainder
4308 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4309
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4310<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4311<pre>
4312 &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]4313</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4314
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4315</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4316
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4317</div>
4318
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4319<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4320<h3>
4321 <a name="bitwiseops">Bitwise Binary Operations</a>
4322</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4324<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325
4326<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4327 program. They are generally very efficient instructions and can commonly be
4328 strength reduced from other instructions. They require two operands of the
4329 same type, execute an operation on them, and produce a single value. The
4330 resulting value is the same type as its operands.</p>
4331
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4332<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4333<h4>
4334 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4335</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4336
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4337<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4339<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4341 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4342 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4343 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4344 &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]4345</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4346
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4347<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4349 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4350
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4351<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4352<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4353 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4354 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4355
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4356<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4358 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4359 is (statically or dynamically) negative or equal to or larger than the number
4360 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4361 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4362 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4363
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4364<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4365 <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]4366 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4367 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4368 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4369 they would if the shift were expressed as a mul instruction with the same
4370 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4371
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4372<h5>Example:</h5>
4373<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4374 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4375 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4376 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4377 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4378 &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]4379</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4380
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4381</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4382
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4383<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4384<h4>
4385 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4386</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4387
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4388<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4389
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4390<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4392 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4393 &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]4394</pre>
4395
4396<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4398 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4399
4400<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4401<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4403 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4404
4405<h5>Semantics:</h5>
4406<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4407 significant bits of the result will be filled with zero bits after the shift.
4408 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4409 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4410 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4411 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4412
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4413<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4414 <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]4415 shifted out are non-zero.</p>
4416
4417
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4418<h5>Example:</h5>
4419<pre>
4420 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4421 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4422 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4423 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4424 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4425 &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]4426</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4427
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4428</div>
4429
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4430<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4431<h4>
4432 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4433</h4>
4434
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4435<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4436
4437<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4438<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4439 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4440 &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]4441</pre>
4442
4443<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4444<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4445 operand shifted to the right a specified number of bits with sign
4446 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4447
4448<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4449<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4450 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4451 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4452
4453<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454<p>This instruction always performs an arithmetic shift right operation, The
4455 most significant bits of the result will be filled with the sign bit
4456 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4457 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4458 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4459 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4460
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4461<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4462 <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]4463 shifted out are non-zero.</p>
4464
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4465<h5>Example:</h5>
4466<pre>
4467 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4468 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4469 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4470 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4471 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4472 &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]4473</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4474
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4475</div>
4476
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4477<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4478<h4>
4479 <a name="i_and">'<tt>and</tt>' Instruction</a>
4480</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4481
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4482<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4483
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4484<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4485<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4486 &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]4487</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4488
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4489<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4491 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4492
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4493<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4494<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4495 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4496 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4497
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4498<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4499<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4501<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4502 <tbody>
4503 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4504 <th>In0</th>
4505 <th>In1</th>
4506 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4507 </tr>
4508 <tr>
4509 <td>0</td>
4510 <td>0</td>
4511 <td>0</td>
4512 </tr>
4513 <tr>
4514 <td>0</td>
4515 <td>1</td>
4516 <td>0</td>
4517 </tr>
4518 <tr>
4519 <td>1</td>
4520 <td>0</td>
4521 <td>0</td>
4522 </tr>
4523 <tr>
4524 <td>1</td>
4525 <td>1</td>
4526 <td>1</td>
4527 </tr>
4528 </tbody>
4529</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4531<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4532<pre>
4533 &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]4534 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4535 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4536</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4537</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4538<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4539<h4>
4540 <a name="i_or">'<tt>or</tt>' Instruction</a>
4541</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4542
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4543<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4544
4545<h5>Syntax:</h5>
4546<pre>
4547 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4548</pre>
4549
4550<h5>Overview:</h5>
4551<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4552 two operands.</p>
4553
4554<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4555<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4556 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4557 values. Both arguments must have identical types.</p>
4558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4559<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4560<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4561
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4562<table border="1" cellspacing="0" cellpadding="4">
4563 <tbody>
4564 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4565 <th>In0</th>
4566 <th>In1</th>
4567 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4568 </tr>
4569 <tr>
4570 <td>0</td>
4571 <td>0</td>
4572 <td>0</td>
4573 </tr>
4574 <tr>
4575 <td>0</td>
4576 <td>1</td>
4577 <td>1</td>
4578 </tr>
4579 <tr>
4580 <td>1</td>
4581 <td>0</td>
4582 <td>1</td>
4583 </tr>
4584 <tr>
4585 <td>1</td>
4586 <td>1</td>
4587 <td>1</td>
4588 </tr>
4589 </tbody>
4590</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4592<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4593<pre>
4594 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4595 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4596 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4597</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4599</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4601<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4602<h4>
4603 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4604</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4605
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4606<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4607
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4608<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4609<pre>
4610 &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]4611</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4613<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4614<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4615 its two operands. The <tt>xor</tt> is used to implement the "one's
4616 complement" operation, which is the "~" operator in C.</p>
4617
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4618<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4619<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4620 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4621 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4622
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4623<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4624<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4625
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4626<table border="1" cellspacing="0" cellpadding="4">
4627 <tbody>
4628 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4629 <th>In0</th>
4630 <th>In1</th>
4631 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4632 </tr>
4633 <tr>
4634 <td>0</td>
4635 <td>0</td>
4636 <td>0</td>
4637 </tr>
4638 <tr>
4639 <td>0</td>
4640 <td>1</td>
4641 <td>1</td>
4642 </tr>
4643 <tr>
4644 <td>1</td>
4645 <td>0</td>
4646 <td>1</td>
4647 </tr>
4648 <tr>
4649 <td>1</td>
4650 <td>1</td>
4651 <td>0</td>
4652 </tr>
4653 </tbody>
4654</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4656<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4657<pre>
4658 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4659 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4660 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4661 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4662</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4664</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4665
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4666</div>
4667
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4668<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4669<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4670 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4671</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4672
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4673<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4674
4675<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4676 target-independent manner. These instructions cover the element-access and
4677 vector-specific operations needed to process vectors effectively. While LLVM
4678 does directly support these vector operations, many sophisticated algorithms
4679 will want to use target-specific intrinsics to take full advantage of a
4680 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4681
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4682<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4683<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4684 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4685</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4686
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4687<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4688
4689<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4690<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4691 &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]4692</pre>
4693
4694<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4695<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4696 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4697
4698
4699<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4700<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4701 of <a href="#t_vector">vector</a> type. The second operand is an index
4702 indicating the position from which to extract the element. The index may be
4703 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4704
4705<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706<p>The result is a scalar of the same type as the element type of
4707 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4708 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4709 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4710
4711<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4712<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4713 &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]4714</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4715
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4717
4718<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4719<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4720 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4721</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4723<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4724
4725<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4726<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4727 &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]4728</pre>
4729
4730<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4732 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4733
4734<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4735<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4736 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4737 whose type must equal the element type of the first operand. The third
4738 operand is an index indicating the position at which to insert the value.
4739 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4740
4741<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4742<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4743 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4744 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4745 results are undefined.</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>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4749 &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]4750</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4751
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4755<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4756 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4757</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4759<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4760
4761<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4762<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4763 &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]4764</pre>
4765
4766<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4768 from two input vectors, returning a vector with the same element type as the
4769 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4770
4771<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4772<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
Duncan Sandsb5a1bf42012-06-14 14:58:28 +0000[diff] [blame]4773 with the same type. The third argument is a shuffle mask whose
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4774 element type is always 'i32'. The result of the instruction is a vector
4775 whose length is the same as the shuffle mask and whose element type is the
4776 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4777
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778<p>The shuffle mask operand is required to be a constant vector with either
4779 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4780
4781<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4782<p>The elements of the two input vectors are numbered from left to right across
4783 both of the vectors. The shuffle mask operand specifies, for each element of
4784 the result vector, which element of the two input vectors the result element
4785 gets. The element selector may be undef (meaning "don't care") and the
4786 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4787
4788<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4789<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4790 &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]4791 &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]4792 &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]4793 &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]4794 &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]4795 &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]4796 &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]4797 &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]4798</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4800</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4801
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4802</div>
4803
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4804<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4805<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4806 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4807</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4808
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4809<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4810
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4811<p>LLVM supports several instructions for working with
4812 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4813
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4814<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4815<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4816 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4817</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4818
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4819<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4820
4821<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4822<pre>
4823 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4824</pre>
4825
4826<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4827<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4828 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4829
4830<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4831<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4832 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4833 <a href="#t_array">array</a> type. The operands are constant indices to
4834 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4835 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4836 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4837 <ul>
4838 <li>Since the value being indexed is not a pointer, the first index is
4839 omitted and assumed to be zero.</li>
4840 <li>At least one index must be specified.</li>
4841 <li>Not only struct indices but also array indices must be in
4842 bounds.</li>
4843 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4844
4845<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4846<p>The result is the value at the position in the aggregate specified by the
4847 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4848
4849<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4850<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4851 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4852</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4854</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4855
4856<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4857<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4858 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4859</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4860
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4861<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4862
4863<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4864<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4865 &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]4866</pre>
4867
4868<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4869<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4870 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4871
4872<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4873<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4874 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4875 <a href="#t_array">array</a> type. The second operand is a first-class
4876 value to insert. The following operands are constant indices indicating
4877 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]4878 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4879 value to insert must have the same type as the value identified by the
4880 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4881
4882<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4884 that of <tt>val</tt> except that the value at the position specified by the
4885 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4886
4887<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4888<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4889 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4890 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4891 %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]4892</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4893
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4894</div>
4895
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4896</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4897
4898<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4899<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4900 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4901</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4902
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4903<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4905<p>A key design point of an SSA-based representation is how it represents
4906 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4907 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4908 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4910<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4911<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4912 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4913</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4914
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4915<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4917<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4918<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4919 &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]4920</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4922<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4923<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4924 currently executing function, to be automatically released when this function
4925 returns to its caller. The object is always allocated in the generic address
4926 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4928<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4929<p>The '<tt>alloca</tt>' instruction
4930 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4931 runtime stack, returning a pointer of the appropriate type to the program.
4932 If "NumElements" is specified, it is the number of elements allocated,
4933 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4934 specified, the value result of the allocation is guaranteed to be aligned to
4935 at least that boundary. If not specified, or if zero, the target can choose
4936 to align the allocation on any convenient boundary compatible with the
4937 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4938
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4939<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4941<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4942<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4943 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4944 memory is automatically released when the function returns. The
4945 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4946 variables that must have an address available. When the function returns
4947 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]4948 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4949 reclaimed. Allocating zero bytes is legal, but the result is undefined.
4950 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewycky75d05e62012-03-18 09:35:50 +0000[diff] [blame]4951 not specified.</p>
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4952
4953<p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4954
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4955<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4956<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4957 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4958 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4959 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4960 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4961</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4963</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4965<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4966<h4>
4967 <a name="i_load">'<tt>load</tt>' Instruction</a>
4968</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4969
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4970<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4972<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4973<pre>
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4974 &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]4975 &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]4976 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4977</pre>
4978
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4979<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4980<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4981
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4982<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4983<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4984 from which to load. The pointer must point to
4985 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4986 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4987 number or order of execution of this <tt>load</tt> with other <a
4988 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4989
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4990<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4991 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4992 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4993 not valid on <code>load</code> instructions. Atomic loads produce <a
4994 href="#memorymodel">defined</a> results when they may see multiple atomic
4995 stores. The type of the pointee must be an integer type whose bit width
4996 is a power of two greater than or equal to eight and less than or equal
4997 to a target-specific size limit. <code>align</code> must be explicitly
4998 specified on atomic loads, and the load has undefined behavior if the
4999 alignment is not set to a value which is at least the size in bytes of
5000 the pointee. <code>!nontemporal</code> does not have any defined semantics
5001 for atomic loads.</p>
5002
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5003<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5004 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]5005 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006 alignment for the target. It is the responsibility of the code emitter to
5007 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5008 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5009 produce less efficient code. An alignment of 1 is always safe.</p>
5010
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5011<p>The optional <tt>!nontemporal</tt> metadata must reference a single
5012 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5013 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5014 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
5015 and code generator that this load is not expected to be reused in the cache.
5016 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5017 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5018
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]5019<p>The optional <tt>!invariant.load</tt> metadata must reference a single
5020 metatadata name &lt;index&gt; corresponding to a metadata node with no
5021 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
5022 instruction tells the optimizer and code generator that this load address
5023 points to memory which does not change value during program execution.
5024 The optimizer may then move this load around, for example, by hoisting it
5025 out of loops using loop invariant code motion.</p>
5026
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5027<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5028<p>The location of memory pointed to is loaded. If the value being loaded is of
5029 scalar type then the number of bytes read does not exceed the minimum number
5030 of bytes needed to hold all bits of the type. For example, loading an
5031 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
5032 <tt>i20</tt> with a size that is not an integral number of bytes, the result
5033 is undefined if the value was not originally written using a store of the
5034 same type.</p>
5035
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5036<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5037<pre>
5038 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
5039 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5040 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5041</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5042
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5043</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5044
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5045<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5046<h4>
5047 <a name="i_store">'<tt>store</tt>' Instruction</a>
5048</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5049
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5050<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5052<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5053<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5054 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>
5055 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]5056</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5057
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5058<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5059<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5060
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5061<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5062<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5063 and an address at which to store it. The type of the
5064 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5065 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]5066 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5067 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5068 order of execution of this <tt>store</tt> with other <a
5069 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]5071<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5072 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5073 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5074 valid on <code>store</code> instructions. Atomic loads produce <a
5075 href="#memorymodel">defined</a> results when they may see multiple atomic
5076 stores. The type of the pointee must be an integer type whose bit width
5077 is a power of two greater than or equal to eight and less than or equal
5078 to a target-specific size limit. <code>align</code> must be explicitly
5079 specified on atomic stores, and the store has undefined behavior if the
5080 alignment is not set to a value which is at least the size in bytes of
5081 the pointee. <code>!nontemporal</code> does not have any defined semantics
5082 for atomic stores.</p>
5083
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5084<p>The optional constant "align" argument specifies the alignment of the
5085 operation (that is, the alignment of the memory address). A value of 0 or an
5086 omitted "align" argument means that the operation has the preferential
5087 alignment for the target. It is the responsibility of the code emitter to
5088 ensure that the alignment information is correct. Overestimating the
5089 alignment results in an undefined behavior. Underestimating the alignment may
5090 produce less efficient code. An alignment of 1 is always safe.</p>
5091
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5092<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5093 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5094 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5095 instruction tells the optimizer and code generator that this load is
5096 not expected to be reused in the cache. The code generator may
5097 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5098 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5099
5100
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5101<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5103 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5104 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5105 does not exceed the minimum number of bytes needed to hold all bits of the
5106 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5107 writing a value of a type like <tt>i20</tt> with a size that is not an
5108 integral number of bytes, it is unspecified what happens to the extra bits
5109 that do not belong to the type, but they will typically be overwritten.</p>
5110
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5111<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5112<pre>
5113 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]5114 store i32 3, i32* %ptr <i>; yields {void}</i>
5115 %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]5116</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5118</div>
5119
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5120<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5121<h4>
5122<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5123</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5124
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5125<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5126
5127<h5>Syntax:</h5>
5128<pre>
5129 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5130</pre>
5131
5132<h5>Overview:</h5>
5133<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5134between operations.</p>
5135
5136<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5137href="#ordering">ordering</a> argument which defines what
5138<i>synchronizes-with</i> edges they add. They can only be given
5139<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5140<code>seq_cst</code> orderings.</p>
5141
5142<h5>Semantics:</h5>
5143<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5144semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5145<code>acquire</code> ordering semantics if and only if there exist atomic
5146operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5147<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5148<var>X</var> modifies <var>M</var> (either directly or through some side effect
5149of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5150<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5151<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5152than an explicit <code>fence</code>, one (but not both) of the atomic operations
5153<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5154<code>acquire</code> (resp.) ordering constraint and still
5155<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5156<i>happens-before</i> edge.</p>
5157
5158<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5159having both <code>acquire</code> and <code>release</code> semantics specified
5160above, participates in the global program order of other <code>seq_cst</code>
5161operations and/or fences.</p>
5162
5163<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5164specifies that the fence only synchronizes with other fences in the same
5165thread. (This is useful for interacting with signal handlers.)</p>
5166
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5167<h5>Example:</h5>
5168<pre>
5169 fence acquire <i>; yields {void}</i>
5170 fence singlethread seq_cst <i>; yields {void}</i>
5171</pre>
5172
5173</div>
5174
5175<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5176<h4>
5177<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5178</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5179
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5180<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5181
5182<h5>Syntax:</h5>
5183<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5184 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]5185</pre>
5186
5187<h5>Overview:</h5>
5188<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5189It loads a value in memory and compares it to a given value. If they are
5190equal, it stores a new value into the memory.</p>
5191
5192<h5>Arguments:</h5>
5193<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5194address to operate on, a value to compare to the value currently be at that
5195address, and a new value to place at that address if the compared values are
5196equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5197bit width is a power of two greater than or equal to eight and less than
5198or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5199'<var>&lt;new&gt;</var>' must have the same type, and the type of
5200'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5201<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5202optimizer is not allowed to modify the number or order of execution
5203of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5204operations</a>.</p>
5205
5206<!-- FIXME: Extend allowed types. -->
5207
5208<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5209<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5210
5211<p>The optional "<code>singlethread</code>" argument declares that the
5212<code>cmpxchg</code> is only atomic with respect to code (usually signal
5213handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5214cmpxchg is atomic with respect to all other code in the system.</p>
5215
5216<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5217the size in memory of the operand.
5218
5219<h5>Semantics:</h5>
5220<p>The contents of memory at the location specified by the
5221'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5222'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5223'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5224is returned.
5225
5226<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5227purpose of identifying <a href="#release_sequence">release sequences</a>. A
5228failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5229parameter determined by dropping any <code>release</code> part of the
5230<code>cmpxchg</code>'s ordering.</p>
5231
5232<!--
5233FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5234optimization work on ARM.)
5235
5236FIXME: Is a weaker ordering constraint on failure helpful in practice?
5237-->
5238
5239<h5>Example:</h5>
5240<pre>
5241entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5242 %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]5243 <a href="#i_br">br</a> label %loop
5244
5245loop:
5246 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5247 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5248 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5249 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5250 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5251
5252done:
5253 ...
5254</pre>
5255
5256</div>
5257
5258<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5259<h4>
5260<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5261</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5262
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5263<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5264
5265<h5>Syntax:</h5>
5266<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5267 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]5268</pre>
5269
5270<h5>Overview:</h5>
5271<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5272
5273<h5>Arguments:</h5>
5274<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5275operation to apply, an address whose value to modify, an argument to the
5276operation. The operation must be one of the following keywords:</p>
5277<ul>
5278 <li>xchg</li>
5279 <li>add</li>
5280 <li>sub</li>
5281 <li>and</li>
5282 <li>nand</li>
5283 <li>or</li>
5284 <li>xor</li>
5285 <li>max</li>
5286 <li>min</li>
5287 <li>umax</li>
5288 <li>umin</li>
5289</ul>
5290
5291<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5292bit width is a power of two greater than or equal to eight and less than
5293or equal to a target-specific size limit. The type of the
5294'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5295If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5296optimizer is not allowed to modify the number or order of execution of this
5297<code>atomicrmw</code> with other <a href="#volatile">volatile
5298 operations</a>.</p>
5299
5300<!-- FIXME: Extend allowed types. -->
5301
5302<h5>Semantics:</h5>
5303<p>The contents of memory at the location specified by the
5304'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5305back. The original value at the location is returned. The modification is
5306specified by the <var>operation</var> argument:</p>
5307
5308<ul>
5309 <li>xchg: <code>*ptr = val</code></li>
5310 <li>add: <code>*ptr = *ptr + val</code></li>
5311 <li>sub: <code>*ptr = *ptr - val</code></li>
5312 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5313 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5314 <li>or: <code>*ptr = *ptr | val</code></li>
5315 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5316 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5317 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5318 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5319 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5320</ul>
5321
5322<h5>Example:</h5>
5323<pre>
5324 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5325</pre>
5326
5327</div>
5328
5329<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5330<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5331 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5332</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5333
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5334<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5335
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5336<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5337<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5338 &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]5339 &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]5340 &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]5341</pre>
5342
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5343<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5344<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5345 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5346 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5347
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5348<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5349<p>The first argument is always a pointer or a vector of pointers,
5350 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5351 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5352 elements of the aggregate object are indexed. The interpretation of each
5353 index is dependent on the type being indexed into. The first index always
5354 indexes the pointer value given as the first argument, the second index
5355 indexes a value of the type pointed to (not necessarily the value directly
5356 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5357 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5358 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5359 can never be pointers, since that would require loading the pointer before
5360 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5361
5362<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]5363 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5364 integer <b>constants</b> are allowed. When indexing into an array, pointer
5365 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]5366 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5368<p>For example, let's consider a C code fragment and how it gets compiled to
5369 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5370
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5371<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5372struct RT {
5373 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5374 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5375 char C;
5376};
5377struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5378 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5379 double Y;
5380 struct RT Z;
5381};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5382
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5383int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5384 return &amp;s[1].Z.B[5][13];
5385}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5386</pre>
5387
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5388<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5389
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5390<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5391%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5392%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5393
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5394define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5395entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5396 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5397 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5398}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5399</pre>
5400
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5401<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5402<p>In the example above, the first index is indexing into the
5403 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5404 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5405 structure. The second index indexes into the third element of the structure,
5406 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5407 type, another structure. The third index indexes into the second element of
5408 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5409 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5410 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5411 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5412
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5413<p>Note that it is perfectly legal to index partially through a structure,
5414 returning a pointer to an inner element. Because of this, the LLVM code for
5415 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5416
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5417<pre class="doc_code">
5418define i32* @foo(%struct.ST* %s) {
5419 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5420 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5421 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5422 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5423 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5424 ret i32* %t5
5425}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5426</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5427
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5428<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5429 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5430 base pointer is not an <i>in bounds</i> address of an allocated object,
5431 or if any of the addresses that would be formed by successive addition of
5432 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5433 precise signed arithmetic are not an <i>in bounds</i> address of that
5434 allocated object. The <i>in bounds</i> addresses for an allocated object
5435 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5436 byte past the end.
5437 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5438 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5439
5440<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]5441 the base address with silently-wrapping two's complement arithmetic. If the
5442 offsets have a different width from the pointer, they are sign-extended or
5443 truncated to the width of the pointer. The result value of the
5444 <tt>getelementptr</tt> may be outside the object pointed to by the base
5445 pointer. The result value may not necessarily be used to access memory
5446 though, even if it happens to point into allocated storage. See the
5447 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5448 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5449
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5450<p>The getelementptr instruction is often confusing. For some more insight into
5451 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5452
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5453<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5454<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5455 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5456 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5457 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5458 %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]5459 <i>; yields i8*:eptr</i>
5460 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5461 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5462 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5463</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5464
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5465<p>In cases where the pointer argument is a vector of pointers, only a
5466 single index may be used, and the number of vector elements has to be
5467 the same. For example: </p>
5468<pre class="doc_code">
5469 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5470</pre>
5471
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5472</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5473
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5474</div>
5475
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5476<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5477<h3>
5478 <a name="convertops">Conversion Operations</a>
5479</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5481<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5482
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5483<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5484 which all take a single operand and a type. They perform various bit
5485 conversions on the operand.</p>
5486
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5487<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5488<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5489 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5490</h4>
5491
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5492<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5493
5494<h5>Syntax:</h5>
5495<pre>
5496 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5497</pre>
5498
5499<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5501 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5502
5503<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5504<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc 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 larger than
5508 the bit size of the destination type, <tt>ty2</tt>.
5509 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5510
5511<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5512<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5513 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5514 source size must be larger than the destination size, <tt>trunc</tt> cannot
5515 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5516
5517<h5>Example:</h5>
5518<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5519 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5520 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5521 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5522 %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]5523</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5524
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5525</div>
5526
5527<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5528<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5529 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5530</h4>
5531
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5532<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5533
5534<h5>Syntax:</h5>
5535<pre>
5536 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5537</pre>
5538
5539<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5540<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5541 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5542
5543
5544<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5545<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5546 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5547 of the same number of integers.
5548 The bit size of the <tt>value</tt> must be smaller than
5549 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5550 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5551
5552<h5>Semantics:</h5>
5553<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]5554 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5555
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5556<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]5557
5558<h5>Example:</h5>
5559<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5560 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5561 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5562 %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]5563</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5564
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5565</div>
5566
5567<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5568<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5569 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5570</h4>
5571
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5572<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5573
5574<h5>Syntax:</h5>
5575<pre>
5576 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5577</pre>
5578
5579<h5>Overview:</h5>
5580<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5581
5582<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5583<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5584 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5585 of the same number of integers.
5586 The bit size of the <tt>value</tt> must be smaller than
5587 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5588 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5589
5590<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5592 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5593 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5594
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5595<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]5596
5597<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5598<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5599 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5600 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5601 %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]5602</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5603
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5604</div>
5605
5606<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5607<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5608 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5609</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5610
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5611<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5612
5613<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5614<pre>
5615 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5616</pre>
5617
5618<h5>Overview:</h5>
5619<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5620 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5621
5622<h5>Arguments:</h5>
5623<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5624 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5625 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]5626 <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]5627 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5628
5629<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5630<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5631 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632 <a href="#t_floating">floating point</a> type. If the value cannot fit
5633 within the destination type, <tt>ty2</tt>, then the results are
5634 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5635
5636<h5>Example:</h5>
5637<pre>
5638 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5639 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5640</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5641
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5642</div>
5643
5644<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5645<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5646 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5647</h4>
5648
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5649<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5650
5651<h5>Syntax:</h5>
5652<pre>
5653 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5654</pre>
5655
5656<h5>Overview:</h5>
5657<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]5658 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5659
5660<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5661<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5662 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5663 a <a href="#t_floating">floating point</a> type to cast it to. The source
5664 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5665
5666<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5667<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5668 <a href="#t_floating">floating point</a> type to a larger
5669 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5670 used to make a <i>no-op cast</i> because it always changes bits. Use
5671 <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]5672
5673<h5>Example:</h5>
5674<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5675 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5676 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5677</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5678
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5679</div>
5680
5681<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5682<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5683 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5684</h4>
5685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5686<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5687
5688<h5>Syntax:</h5>
5689<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5690 &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]5691</pre>
5692
5693<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5694<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5695 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5696
5697<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5698<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5699 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5700 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5701 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5702 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5703
5704<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5705<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5706 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5707 towards zero) unsigned integer value. If the value cannot fit
5708 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5709
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5710<h5>Example:</h5>
5711<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5712 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5713 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5714 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5715</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5716
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5717</div>
5718
5719<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5720<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5721 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5722</h4>
5723
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5724<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5725
5726<h5>Syntax:</h5>
5727<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5728 &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]5729</pre>
5730
5731<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5732<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733 <a href="#t_floating">floating point</a> <tt>value</tt> to
5734 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5735
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5736<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5737<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5738 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5739 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5740 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5741 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5742
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5743<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5744<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5746 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5747 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5748
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5749<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5750<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5751 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5752 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5753 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5754</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5755
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5756</div>
5757
5758<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5759<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5760 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5761</h4>
5762
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5763<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5764
5765<h5>Syntax:</h5>
5766<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5767 &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]5768</pre>
5769
5770<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5771<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5773
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5774<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5775<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]5776 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5777 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5778 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5779 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5780
5781<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5782<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5783 integer quantity and converts it to the corresponding floating point
5784 value. If the value cannot fit in the floating point value, the results are
5785 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5786
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5787<h5>Example:</h5>
5788<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5789 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5790 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5791</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5792
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5793</div>
5794
5795<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5796<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5797 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5798</h4>
5799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5800<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5801
5802<h5>Syntax:</h5>
5803<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5804 &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]5805</pre>
5806
5807<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5809 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5810
5811<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5812<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]5813 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5814 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5815 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5816 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5817
5818<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5820 quantity and converts it to the corresponding floating point value. If the
5821 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5822
5823<h5>Example:</h5>
5824<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5825 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5826 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5827</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5828
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5829</div>
5830
5831<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5832<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5833 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5834</h4>
5835
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5836<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5837
5838<h5>Syntax:</h5>
5839<pre>
5840 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5841</pre>
5842
5843<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5844<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5845 pointers <tt>value</tt> to
5846 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5847
5848<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5849<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5850 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5851 pointers, and a type to cast it to
5852 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5853 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5854
5855<h5>Semantics:</h5>
5856<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5858 truncating or zero extending that value to the size of the integer type. If
5859 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5860 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5861 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5862 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5863
5864<h5>Example:</h5>
5865<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5866 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5867 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5868 %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]5869</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5870
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5871</div>
5872
5873<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5874<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5875 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5876</h4>
5877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5878<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5879
5880<h5>Syntax:</h5>
5881<pre>
5882 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5887 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5890<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5891 value to cast, and a type to cast it to, which must be a
5892 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5893
5894<h5>Semantics:</h5>
5895<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5896 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5897 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5898 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5899 than the size of a pointer then a zero extension is done. If they are the
5900 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5901
5902<h5>Example:</h5>
5903<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5904 %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]5905 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5906 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5907 %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]5908</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5909
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5910</div>
5911
5912<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5913<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5914 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5915</h4>
5916
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5917<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5918
5919<h5>Syntax:</h5>
5920<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5921 &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]5922</pre>
5923
5924<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5925<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5926 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5927
5928<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5930 non-aggregate first class value, and a type to cast it to, which must also be
5931 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5932 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5933 identical. If the source type is a pointer, the destination type must also be
5934 a pointer. This instruction supports bitwise conversion of vectors to
5935 integers and to vectors of other types (as long as they have the same
5936 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5937
5938<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5939<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5940 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5941 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5942 stored to memory and read back as type <tt>ty2</tt>.
5943 Pointer (or vector of pointers) types may only be converted to other pointer
5944 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5945 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5946 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5947
5948<h5>Example:</h5>
5949<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5950 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5951 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5952 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5953 %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]5954</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5955
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5956</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5957
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5958</div>
5959
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5960<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5961<h3>
5962 <a name="otherops">Other Operations</a>
5963</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5964
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5965<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5966
5967<p>The instructions in this category are the "miscellaneous" instructions, which
5968 defy better classification.</p>
5969
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5970<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5971<h4>
5972 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5973</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5974
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5975<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5976
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5977<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5978<pre>
5979 &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]5980</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5981
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5983<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5984 boolean values based on comparison of its two integer, integer vector,
5985 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5986
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5987<h5>Arguments:</h5>
5988<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5989 the condition code indicating the kind of comparison to perform. It is not a
5990 value, just a keyword. The possible condition code are:</p>
5991
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5992<ol>
5993 <li><tt>eq</tt>: equal</li>
5994 <li><tt>ne</tt>: not equal </li>
5995 <li><tt>ugt</tt>: unsigned greater than</li>
5996 <li><tt>uge</tt>: unsigned greater or equal</li>
5997 <li><tt>ult</tt>: unsigned less than</li>
5998 <li><tt>ule</tt>: unsigned less or equal</li>
5999 <li><tt>sgt</tt>: signed greater than</li>
6000 <li><tt>sge</tt>: signed greater or equal</li>
6001 <li><tt>slt</tt>: signed less than</li>
6002 <li><tt>sle</tt>: signed less or equal</li>
6003</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]6005<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6006 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
6007 typed. They must also be identical types.</p>
6008
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6009<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6010<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
6011 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6012 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]6013 result, as follows:</p>
6014
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6015<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6016 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6017 <tt>false</tt> otherwise. No sign interpretation is necessary or
6018 performed.</li>
6019
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6020 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6021 <tt>false</tt> otherwise. No sign interpretation is necessary or
6022 performed.</li>
6023
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6024 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6025 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6026
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6027 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6028 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6029 to <tt>op2</tt>.</li>
6030
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6031 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6032 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6033
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6034 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6035 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6036
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6037 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6039
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6040 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6041 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6042 to <tt>op2</tt>.</li>
6043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6044 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6045 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6046
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6047 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6048 <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]6049</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6050
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6051<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6052 values are compared as if they were integers.</p>
6053
6054<p>If the operands are integer vectors, then they are compared element by
6055 element. The result is an <tt>i1</tt> vector with the same number of elements
6056 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6057
6058<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6059<pre>
6060 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6061 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6062 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6063 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6064 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6065 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6066</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6067
6068<p>Note that the code generator does not yet support vector types with
6069 the <tt>icmp</tt> instruction.</p>
6070
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6071</div>
6072
6073<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6074<h4>
6075 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6076</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6078<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6079
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6080<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6081<pre>
6082 &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]6083</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6084
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6085<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6086<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6087 values based on comparison of its operands.</p>
6088
6089<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]6090(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6091
6092<p>If the operands are floating point vectors, then the result type is a vector
6093 of boolean with the same number of elements as the operands being
6094 compared.</p>
6095
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6096<h5>Arguments:</h5>
6097<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6098 the condition code indicating the kind of comparison to perform. It is not a
6099 value, just a keyword. The possible condition code are:</p>
6100
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6101<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6102 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6103 <li><tt>oeq</tt>: ordered and equal</li>
6104 <li><tt>ogt</tt>: ordered and greater than </li>
6105 <li><tt>oge</tt>: ordered and greater than or equal</li>
6106 <li><tt>olt</tt>: ordered and less than </li>
6107 <li><tt>ole</tt>: ordered and less than or equal</li>
6108 <li><tt>one</tt>: ordered and not equal</li>
6109 <li><tt>ord</tt>: ordered (no nans)</li>
6110 <li><tt>ueq</tt>: unordered or equal</li>
6111 <li><tt>ugt</tt>: unordered or greater than </li>
6112 <li><tt>uge</tt>: unordered or greater than or equal</li>
6113 <li><tt>ult</tt>: unordered or less than </li>
6114 <li><tt>ule</tt>: unordered or less than or equal</li>
6115 <li><tt>une</tt>: unordered or not equal</li>
6116 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6117 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6118</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6119
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6120<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6121 <i>unordered</i> means that either operand may be a QNAN.</p>
6122
6123<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6124 a <a href="#t_floating">floating point</a> type or
6125 a <a href="#t_vector">vector</a> of floating point type. They must have
6126 identical types.</p>
6127
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6128<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]6129<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6130 according to the condition code given as <tt>cond</tt>. If the operands are
6131 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6132 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6133 follows:</p>
6134
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6135<ol>
6136 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6138 <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]6139 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6140
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6141 <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]6142 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6143
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6144 <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]6145 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6146
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6147 <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]6148 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6149
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6150 <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]6151 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6152
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6153 <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]6154 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6155
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6156 <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]6157
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6158 <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]6159 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6160
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6161 <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]6162 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6163
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6164 <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]6165 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6166
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6167 <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]6168 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6169
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6170 <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]6171 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6172
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6173 <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]6174 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6175
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6176 <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]6177
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6178 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6179</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6180
6181<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6182<pre>
6183 &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]6184 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6185 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6186 &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]6187</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6188
6189<p>Note that the code generator does not yet support vector types with
6190 the <tt>fcmp</tt> instruction.</p>
6191
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6192</div>
6193
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6194<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6195<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6196 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6197</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6198
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6199<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6200
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6201<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6202<pre>
6203 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6204</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6205
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6206<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6207<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6208 SSA graph representing the function.</p>
6209
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6210<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6211<p>The type of the incoming values is specified with the first type field. After
6212 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6213 one pair for each predecessor basic block of the current block. Only values
6214 of <a href="#t_firstclass">first class</a> type may be used as the value
6215 arguments to the PHI node. Only labels may be used as the label
6216 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6217
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6218<p>There must be no non-phi instructions between the start of a basic block and
6219 the PHI instructions: i.e. PHI instructions must be first in a basic
6220 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6221
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6222<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6223 occur on the edge from the corresponding predecessor block to the current
6224 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6225 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]6226
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6227<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6228<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6229 specified by the pair corresponding to the predecessor basic block that
6230 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6231
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6232<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6233<pre>
6234Loop: ; Infinite loop that counts from 0 on up...
6235 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6236 %nextindvar = add i32 %indvar, 1
6237 br label %Loop
6238</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6240</div>
6241
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6242<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6243<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6244 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6245</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6246
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6247<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6248
6249<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6250<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6251 &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>
6252
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6253 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6254</pre>
6255
6256<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6258 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6259
6260
6261<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6262<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6263 values indicating the condition, and two values of the
6264 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6265 vectors and the condition is a scalar, then entire vectors are selected, not
6266 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6267
6268<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6269<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6270 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6271
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272<p>If the condition is a vector of i1, then the value arguments must be vectors
6273 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6274
6275<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6276<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6277 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6278</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6279
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6280</div>
6281
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6282<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6283<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6284 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6285</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6287<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6289<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6290<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6291 &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]6292</pre>
6293
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6294<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6295<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6297<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6298<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6299
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6300<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6301 <li>The optional "tail" marker indicates that the callee function does not
6302 access any allocas or varargs in the caller. Note that calls may be
6303 marked "tail" even if they do not occur before
6304 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6305 present, the function call is eligible for tail call optimization,
6306 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6307 optimized into a jump</a>. The code generator may optimize calls marked
6308 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6309 sibling call optimization</a> when the caller and callee have
6310 matching signatures, or 2) forced tail call optimization when the
6311 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6312 <ul>
6313 <li>Caller and callee both have the calling
6314 convention <tt>fastcc</tt>.</li>
6315 <li>The call is in tail position (ret immediately follows call and ret
6316 uses value of call or is void).</li>
6317 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6318 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6319 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6320 constraints are met.</a></li>
6321 </ul>
6322 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6323
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6324 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6325 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6326 defaults to using C calling conventions. The calling convention of the
6327 call must match the calling convention of the target function, or else the
6328 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6329
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6330 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6331 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6332 '<tt>inreg</tt>' attributes are valid here.</li>
6333
6334 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6335 type of the return value. Functions that return no value are marked
6336 <tt><a href="#t_void">void</a></tt>.</li>
6337
6338 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6339 being invoked. The argument types must match the types implied by this
6340 signature. This type can be omitted if the function is not varargs and if
6341 the function type does not return a pointer to a function.</li>
6342
6343 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6344 be invoked. In most cases, this is a direct function invocation, but
6345 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6346 to function value.</li>
6347
6348 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6349 signature argument types and parameter attributes. All arguments must be
6350 of <a href="#t_firstclass">first class</a> type. If the function
6351 signature indicates the function accepts a variable number of arguments,
6352 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6353
6354 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6355 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6356 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6357</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6359<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6360<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6361 a specified function, with its incoming arguments bound to the specified
6362 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6363 function, control flow continues with the instruction after the function
6364 call, and the return value of the function is bound to the result
6365 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6366
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6367<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6368<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6369 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6370 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6371 %X = tail call i32 @foo() <i>; yields i32</i>
6372 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6373 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6374
6375 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6376 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6377 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6378 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6379 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6380 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6381</pre>
6382
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6383<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6384standard C99 library as being the C99 library functions, and may perform
6385optimizations or generate code for them under that assumption. This is
6386something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6387freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6388
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6389</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6390
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6391<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6392<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6393 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6394</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6395
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6396<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6397
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6398<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6399<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6400 &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]6401</pre>
6402
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6403<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6404<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6405 the "variable argument" area of a function call. It is used to implement the
6406 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6407
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6408<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6409<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6410 argument. It returns a value of the specified argument type and increments
6411 the <tt>va_list</tt> to point to the next argument. The actual type
6412 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6413
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6414<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6415<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6416 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6417 to the next argument. For more information, see the variable argument
6418 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6419
6420<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]6421 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6422 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6423
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6424<p><tt>va_arg</tt> is an LLVM instruction instead of
6425 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6426 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6427
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6428<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6429<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6430
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6431<p>Note that the code generator does not yet fully support va_arg on many
6432 targets. Also, it does not currently support va_arg with aggregate types on
6433 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6435</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6436
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6437<!-- _______________________________________________________________________ -->
6438<h4>
6439 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6440</h4>
6441
6442<div>
6443
6444<h5>Syntax:</h5>
6445<pre>
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6446 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6447 &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]6448
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6449 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6450 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6451</pre>
6452
6453<h5>Overview:</h5>
6454<p>The '<tt>landingpad</tt>' instruction is used by
6455 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6456 system</a> to specify that a basic block is a landing pad &mdash; one where
6457 the exception lands, and corresponds to the code found in the
6458 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6459 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6460 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6461 type <tt>resultty</tt>.</p>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6462
6463<h5>Arguments:</h5>
6464<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6465 function associated with the unwinding mechanism. The optional
6466 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6467
6468<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6469 or <tt>filter</tt> &mdash; and contains the global variable representing the
6470 "type" that may be caught or filtered respectively. Unlike the
6471 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6472 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6473 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6474 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6475
6476<h5>Semantics:</h5>
6477<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6478 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6479 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6480 calling conventions, how the personality function results are represented in
6481 LLVM IR is target specific.</p>
6482
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6483<p>The clauses are applied in order from top to bottom. If two
6484 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6485 clauses from the calling function are appended to the list of clauses.
6486 When the call stack is being unwound due to an exception being thrown, the
6487 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6488 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6489 unwinding continues further up the call stack.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6490
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6491<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6492
6493<ul>
6494 <li>A landing pad block is a basic block which is the unwind destination of an
6495 '<tt>invoke</tt>' instruction.</li>
6496 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6497 first non-PHI instruction.</li>
6498 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6499 pad block.</li>
6500 <li>A basic block that is not a landing pad block may not include a
6501 '<tt>landingpad</tt>' instruction.</li>
6502 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6503 personality function.</li>
6504</ul>
6505
6506<h5>Example:</h5>
6507<pre>
6508 ;; A landing pad which can catch an integer.
6509 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6510 catch i8** @_ZTIi
6511 ;; A landing pad that is a cleanup.
6512 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6513 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6514 ;; A landing pad which can catch an integer and can only throw a double.
6515 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6516 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6517 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6518</pre>
6519
6520</div>
6521
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6522</div>
6523
6524</div>
6525
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6526<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6527<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6528<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6529
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6530<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6531
6532<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6533 well known names and semantics and are required to follow certain
6534 restrictions. Overall, these intrinsics represent an extension mechanism for
6535 the LLVM language that does not require changing all of the transformations
6536 in LLVM when adding to the language (or the bitcode reader/writer, the
6537 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6538
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6539<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6541 begin with this prefix. Intrinsic functions must always be external
6542 functions: you cannot define the body of intrinsic functions. Intrinsic
6543 functions may only be used in call or invoke instructions: it is illegal to
6544 take the address of an intrinsic function. Additionally, because intrinsic
6545 functions are part of the LLVM language, it is required if any are added that
6546 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6547
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6549 family of functions that perform the same operation but on different data
6550 types. Because LLVM can represent over 8 million different integer types,
6551 overloading is used commonly to allow an intrinsic function to operate on any
6552 integer type. One or more of the argument types or the result type can be
6553 overloaded to accept any integer type. Argument types may also be defined as
6554 exactly matching a previous argument's type or the result type. This allows
6555 an intrinsic function which accepts multiple arguments, but needs all of them
6556 to be of the same type, to only be overloaded with respect to a single
6557 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6558
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6559<p>Overloaded intrinsics will have the names of its overloaded argument types
6560 encoded into its function name, each preceded by a period. Only those types
6561 which are overloaded result in a name suffix. Arguments whose type is matched
6562 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6563 can take an integer of any width and returns an integer of exactly the same
6564 integer width. This leads to a family of functions such as
6565 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6566 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6567 suffix is required. Because the argument's type is matched against the return
6568 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6569
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6570<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6571 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6572
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6573<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6574<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6575 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6576</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6577
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6578<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6579
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6580<p>Variable argument support is defined in LLVM with
6581 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6582 intrinsic functions. These functions are related to the similarly named
6583 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6584
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585<p>All of these functions operate on arguments that use a target-specific value
6586 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6587 not define what this type is, so all transformations should be prepared to
6588 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6589
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6590<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]6591 instruction and the variable argument handling intrinsic functions are
6592 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6593
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6594<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6595define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6596 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6597 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6598 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6599 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6600
6601 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6602 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6603
6604 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6605 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6606 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6607 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6608 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6609
6610 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6611 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6612 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6613}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6614
6615declare void @llvm.va_start(i8*)
6616declare void @llvm.va_copy(i8*, i8*)
6617declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6618</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6619
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6620<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6621<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6622 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6623</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6624
6625
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6626<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6627
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6628<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6629<pre>
6630 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6631</pre>
6632
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6633<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6635 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]6636
6637<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6638<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]6639
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6640<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6641<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]6642 macro available in C. In a target-dependent way, it initializes
6643 the <tt>va_list</tt> element to which the argument points, so that the next
6644 call to <tt>va_arg</tt> will produce the first variable argument passed to
6645 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6646 need to know the last argument of the function as the compiler can figure
6647 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6649</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6650
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6651<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6652<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6653 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6654</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6655
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6656<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6657
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6658<h5>Syntax:</h5>
6659<pre>
6660 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6661</pre>
6662
6663<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6664<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6665 which has been initialized previously
6666 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6667 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6668
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6669<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6670<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]6671
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6672<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6673<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]6674 macro available in C. In a target-dependent way, it destroys
6675 the <tt>va_list</tt> element to which the argument points. Calls
6676 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6677 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6678 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6679
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6680</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6681
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6682<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6683<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6684 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6685</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6686
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6687<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6688
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6689<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6690<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6691 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6692</pre>
6693
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6694<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6695<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6696 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6697
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6698<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6699<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]6700 The second argument is a pointer to a <tt>va_list</tt> element to copy
6701 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6702
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6703<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6704<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]6705 macro available in C. In a target-dependent way, it copies the
6706 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6707 element. This intrinsic is necessary because
6708 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6709 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6710
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6711</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6712
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6713</div>
6714
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6715<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6716<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6717 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6718</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6719
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6720<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6721
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6722<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6723Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6724intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6725roots on the stack</a>, as well as garbage collector implementations that
6726require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6727barriers. Front-ends for type-safe garbage collected languages should generate
6728these intrinsics to make use of the LLVM garbage collectors. For more details,
6729see <a href="GarbageCollection.html">Accurate Garbage Collection with
6730LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6731
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6732<p>The garbage collection intrinsics only operate on objects in the generic
6733 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6734
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6735<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6736<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6737 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6738</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6739
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6740<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6741
6742<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6743<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6744 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6745</pre>
6746
6747<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6748<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]6749 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6750
6751<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6752<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6753 root pointer. The second pointer (which must be either a constant or a
6754 global value address) contains the meta-data to be associated with the
6755 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6756
6757<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6758<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]6759 location. At compile-time, the code generator generates information to allow
6760 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6761 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6762 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6763
6764</div>
6765
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6766<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6767<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6768 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6769</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6770
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6771<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6772
6773<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6774<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6775 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6776</pre>
6777
6778<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6779<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6780 locations, allowing garbage collector implementations that require read
6781 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6782
6783<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6784<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]6785 allocated from the garbage collector. The first object is a pointer to the
6786 start of the referenced object, if needed by the language runtime (otherwise
6787 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6788
6789<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6790<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6791 instruction, but may be replaced with substantially more complex code by the
6792 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6793 may only be used in a function which <a href="#gc">specifies a GC
6794 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6795
6796</div>
6797
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6798<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6799<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6800 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6801</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6803<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6804
6805<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6806<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6807 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6808</pre>
6809
6810<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6811<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6812 locations, allowing garbage collector implementations that require write
6813 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6814
6815<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6816<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]6817 object to store it to, and the third is the address of the field of Obj to
6818 store to. If the runtime does not require a pointer to the object, Obj may
6819 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6820
6821<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6822<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6823 instruction, but may be replaced with substantially more complex code by the
6824 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6825 may only be used in a function which <a href="#gc">specifies a GC
6826 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6827
6828</div>
6829
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6830</div>
6831
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6832<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6833<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6834 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6835</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6837<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6838
6839<p>These intrinsics are provided by LLVM to expose special features that may
6840 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6841
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6842<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6843<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6844 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6845</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6846
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6847<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6848
6849<h5>Syntax:</h5>
6850<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6851 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6852</pre>
6853
6854<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6855<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6856 target-specific value indicating the return address of the current function
6857 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6858
6859<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6860<p>The argument to this intrinsic indicates which function to return the address
6861 for. Zero indicates the calling function, one indicates its caller, etc.
6862 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6863
6864<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6865<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6866 indicating the return address of the specified call frame, or zero if it
6867 cannot be identified. The value returned by this intrinsic is likely to be
6868 incorrect or 0 for arguments other than zero, so it should only be used for
6869 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6870
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6871<p>Note that calling this intrinsic does not prevent function inlining or other
6872 aggressive transformations, so the value returned may not be that of the
6873 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6874
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6875</div>
6876
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6877<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6878<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6879 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6880</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6881
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6882<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6883
6884<h5>Syntax:</h5>
6885<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6886 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6887</pre>
6888
6889<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6890<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6891 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6892
6893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6894<p>The argument to this intrinsic indicates which function to return the frame
6895 pointer for. Zero indicates the calling function, one indicates its caller,
6896 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6897
6898<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6899<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6900 indicating the frame address of the specified call frame, or zero if it
6901 cannot be identified. The value returned by this intrinsic is likely to be
6902 incorrect or 0 for arguments other than zero, so it should only be used for
6903 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905<p>Note that calling this intrinsic does not prevent function inlining or other
6906 aggressive transformations, so the value returned may not be that of the
6907 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6908
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6909</div>
6910
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6911<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6912<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6913 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6914</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6915
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6916<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6917
6918<h5>Syntax:</h5>
6919<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6920 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6921</pre>
6922
6923<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6925 of the function stack, for use
6926 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6927 useful for implementing language features like scoped automatic variable
6928 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6929
6930<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6931<p>This intrinsic returns a opaque pointer value that can be passed
6932 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6933 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6934 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6935 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6936 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6937 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6938
6939</div>
6940
6941<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6942<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6943 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6944</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6945
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6946<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6947
6948<h5>Syntax:</h5>
6949<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6950 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6951</pre>
6952
6953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6955 the function stack to the state it was in when the
6956 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6957 executed. This is useful for implementing language features like scoped
6958 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6959
6960<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6961<p>See the description
6962 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6963
6964</div>
6965
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6966<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6967<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6968 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6969</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6971<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6972
6973<h5>Syntax:</h5>
6974<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6975 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]6976</pre>
6977
6978<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6980 insert a prefetch instruction if supported; otherwise, it is a noop.
6981 Prefetches have no effect on the behavior of the program but can change its
6982 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6983
6984<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6985<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6986 specifier determining if the fetch should be for a read (0) or write (1),
6987 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6988 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6989 specifies whether the prefetch is performed on the data (1) or instruction (0)
6990 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6991 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6992
6993<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994<p>This intrinsic does not modify the behavior of the program. In particular,
6995 prefetches cannot trap and do not produce a value. On targets that support
6996 this intrinsic, the prefetch can provide hints to the processor cache for
6997 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6998
6999</div>
7000
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7001<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7002<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7003 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7004</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7005
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7006<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7007
7008<h5>Syntax:</h5>
7009<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]7010 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7011</pre>
7012
7013<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
7015 Counter (PC) in a region of code to simulators and other tools. The method
7016 is target specific, but it is expected that the marker will use exported
7017 symbols to transmit the PC of the marker. The marker makes no guarantees
7018 that it will remain with any specific instruction after optimizations. It is
7019 possible that the presence of a marker will inhibit optimizations. The
7020 intended use is to be inserted after optimizations to allow correlations of
7021 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7022
7023<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7024<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7025
7026<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7027<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7028 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7029
7030</div>
7031
Andrew Lenharth51b8d542005-11-11 16:47:30 +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_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7035</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7036
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7037<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7038
7039<h5>Syntax:</h5>
7040<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7041 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7042</pre>
7043
7044<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7045<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
7046 counter register (or similar low latency, high accuracy clocks) on those
7047 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7048 should map to RPCC. As the backing counters overflow quickly (on the order
7049 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7050
7051<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052<p>When directly supported, reading the cycle counter should not modify any
7053 memory. Implementations are allowed to either return a application specific
7054 value or a system wide value. On backends without support, this is lowered
7055 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7056
7057</div>
7058
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7059</div>
7060
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7061<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7062<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7063 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7064</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7065
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7066<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7067
7068<p>LLVM provides intrinsics for a few important standard C library functions.
7069 These intrinsics allow source-language front-ends to pass information about
7070 the alignment of the pointer arguments to the code generator, providing
7071 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7072
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7073<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7074<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7075 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7076</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7077
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7078<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7079
7080<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081<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]7082 integer bit width and for different address spaces. Not all targets support
7083 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7084
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7085<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7086 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]7087 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7088 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]7089 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7090</pre>
7091
7092<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7093<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7094 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7095
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7096<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7097 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7098 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7099
7100<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7101
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7102<p>The first argument is a pointer to the destination, the second is a pointer
7103 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7104 number of bytes to copy, the fourth argument is the alignment of the
7105 source and destination locations, and the fifth is a boolean indicating a
7106 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7107
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7108<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]7109 then the caller guarantees that both the source and destination pointers are
7110 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7111
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7112<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7113 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7114 The detailed access behavior is not very cleanly specified and it is unwise
7115 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7116
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7117<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7118
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7120 source location to the destination location, which are not allowed to
7121 overlap. It copies "len" bytes of memory over. If the argument is known to
7122 be aligned to some boundary, this can be specified as the fourth argument,
7123 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7124
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7125</div>
7126
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7127<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7128<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7129 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7130</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7132<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7133
7134<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7135<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]7136 width and for different address space. Not all targets support all bit
7137 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7138
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7139<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7140 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]7141 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7142 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]7143 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7144</pre>
7145
7146<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7147<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7148 source location to the destination location. It is similar to the
7149 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7150 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7152<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7153 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7154 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7155
7156<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7158<p>The first argument is a pointer to the destination, the second is a pointer
7159 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7160 number of bytes to copy, the fourth argument is the alignment of the
7161 source and destination locations, and the fifth is a boolean indicating a
7162 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7163
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7164<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]7165 then the caller guarantees that the source and destination pointers are
7166 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7167
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7168<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7169 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7170 The detailed access behavior is not very cleanly specified and it is unwise
7171 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7172
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7173<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7174
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7175<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7176 source location to the destination location, which may overlap. It copies
7177 "len" bytes of memory over. If the argument is known to be aligned to some
7178 boundary, this can be specified as the fourth argument, otherwise it should
7179 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7180
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7181</div>
7182
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7183<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7184<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7185 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7186</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7187
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7188<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7189
7190<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7191<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]7192 width and for different address spaces. However, not all targets support all
7193 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7194
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7195<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7196 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7197 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7198 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7199 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7200</pre>
7201
7202<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7203<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7204 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7205
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7206<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7207 intrinsic does not return a value and takes extra alignment/volatile
7208 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7209
7210<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7211<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]7212 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7213 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7214 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7215
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7216<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]7217 then the caller guarantees that the destination pointer is aligned to that
7218 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7219
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7220<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7221 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7222 The detailed access behavior is not very cleanly specified and it is unwise
7223 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7224
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7225<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7226<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7227 at the destination location. If the argument is known to be aligned to some
7228 boundary, this can be specified as the fourth argument, otherwise it should
7229 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7230
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7231</div>
7232
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7233<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7234<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7235 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7236</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7237
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7238<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7239
7240<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7241<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7242 floating point or vector of floating point type. Not all targets support all
7243 types however.</p>
7244
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7245<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7246 declare float @llvm.sqrt.f32(float %Val)
7247 declare double @llvm.sqrt.f64(double %Val)
7248 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7249 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7250 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7251</pre>
7252
7253<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7254<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7255 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7256 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7257 behavior for negative numbers other than -0.0 (which allows for better
7258 optimization, because there is no need to worry about errno being
7259 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]7260
7261<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7262<p>The argument and return value are floating point numbers of the same
7263 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7264
7265<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7266<p>This function returns the sqrt of the specified operand if it is a
7267 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7268
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7269</div>
7270
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7271<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7272<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7273 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7274</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7275
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7276<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7277
7278<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7279<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7280 floating point or vector of floating point type. Not all targets support all
7281 types however.</p>
7282
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7283<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7284 declare float @llvm.powi.f32(float %Val, i32 %power)
7285 declare double @llvm.powi.f64(double %Val, i32 %power)
7286 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7287 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7288 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7289</pre>
7290
7291<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7292<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7293 specified (positive or negative) power. The order of evaluation of
7294 multiplications is not defined. When a vector of floating point type is
7295 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7296
7297<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7298<p>The second argument is an integer power, and the first is a value to raise to
7299 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7300
7301<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7302<p>This function returns the first value raised to the second power with an
7303 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7304
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7305</div>
7306
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7307<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7308<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7309 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7310</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7311
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7312<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7313
7314<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7315<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7316 floating point or vector of floating point type. Not all targets support all
7317 types however.</p>
7318
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7319<pre>
7320 declare float @llvm.sin.f32(float %Val)
7321 declare double @llvm.sin.f64(double %Val)
7322 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7323 declare fp128 @llvm.sin.f128(fp128 %Val)
7324 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7325</pre>
7326
7327<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7328<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7329
7330<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7331<p>The argument and return value are floating point numbers of the same
7332 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7333
7334<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7335<p>This function returns the sine of the specified operand, returning the same
7336 values as the libm <tt>sin</tt> functions would, and handles error conditions
7337 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7338
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7339</div>
7340
7341<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7342<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7343 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7344</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7345
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7346<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7347
7348<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7350 floating point or vector of floating point type. Not all targets support all
7351 types however.</p>
7352
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7353<pre>
7354 declare float @llvm.cos.f32(float %Val)
7355 declare double @llvm.cos.f64(double %Val)
7356 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7357 declare fp128 @llvm.cos.f128(fp128 %Val)
7358 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7359</pre>
7360
7361<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7362<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7363
7364<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7365<p>The argument and return value are floating point numbers of the same
7366 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7367
7368<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7369<p>This function returns the cosine of the specified operand, returning the same
7370 values as the libm <tt>cos</tt> functions would, and handles error conditions
7371 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7372
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7373</div>
7374
7375<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7376<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7377 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7378</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7379
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7380<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7381
7382<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7383<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7384 floating point or vector of floating point type. Not all targets support all
7385 types however.</p>
7386
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7387<pre>
7388 declare float @llvm.pow.f32(float %Val, float %Power)
7389 declare double @llvm.pow.f64(double %Val, double %Power)
7390 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7391 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7392 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7393</pre>
7394
7395<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7396<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7397 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7398
7399<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7400<p>The second argument is a floating point power, and the first is a value to
7401 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7402
7403<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7404<p>This function returns the first value raised to the second power, returning
7405 the same values as the libm <tt>pow</tt> functions would, and handles error
7406 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7407
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7408</div>
7409
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7410<!-- _______________________________________________________________________ -->
7411<h4>
7412 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7413</h4>
7414
7415<div>
7416
7417<h5>Syntax:</h5>
7418<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7419 floating point or vector of floating point type. Not all targets support all
7420 types however.</p>
7421
7422<pre>
7423 declare float @llvm.exp.f32(float %Val)
7424 declare double @llvm.exp.f64(double %Val)
7425 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7426 declare fp128 @llvm.exp.f128(fp128 %Val)
7427 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7428</pre>
7429
7430<h5>Overview:</h5>
7431<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7432
7433<h5>Arguments:</h5>
7434<p>The argument and return value are floating point numbers of the same
7435 type.</p>
7436
7437<h5>Semantics:</h5>
7438<p>This function returns the same values as the libm <tt>exp</tt> functions
7439 would, and handles error conditions in the same way.</p>
7440
7441</div>
7442
7443<!-- _______________________________________________________________________ -->
7444<h4>
7445 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7446</h4>
7447
7448<div>
7449
7450<h5>Syntax:</h5>
7451<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7452 floating point or vector of floating point type. Not all targets support all
7453 types however.</p>
7454
7455<pre>
7456 declare float @llvm.log.f32(float %Val)
7457 declare double @llvm.log.f64(double %Val)
7458 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7459 declare fp128 @llvm.log.f128(fp128 %Val)
7460 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7461</pre>
7462
7463<h5>Overview:</h5>
7464<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7465
7466<h5>Arguments:</h5>
7467<p>The argument and return value are floating point numbers of the same
7468 type.</p>
7469
7470<h5>Semantics:</h5>
7471<p>This function returns the same values as the libm <tt>log</tt> functions
7472 would, and handles error conditions in the same way.</p>
7473
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7474</div>
7475
7476<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7477<h4>
7478 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7479</h4>
7480
7481<div>
7482
7483<h5>Syntax:</h5>
7484<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7485 floating point or vector of floating point type. Not all targets support all
7486 types however.</p>
7487
7488<pre>
7489 declare float @llvm.fma.f32(float %a, float %b, float %c)
7490 declare double @llvm.fma.f64(double %a, double %b, double %c)
7491 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7492 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7493 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7494</pre>
7495
7496<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7497<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7498 operation.</p>
7499
7500<h5>Arguments:</h5>
7501<p>The argument and return value are floating point numbers of the same
7502 type.</p>
7503
7504<h5>Semantics:</h5>
7505<p>This function returns the same values as the libm <tt>fma</tt> functions
7506 would.</p>
7507
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7508</div>
7509
Peter Collingbourne168a4c32012-07-03 12:25:40 +0000[diff] [blame]7510<!-- _______________________________________________________________________ -->
7511<h4>
7512 <a name="int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a>
7513</h4>
7514
7515<div>
7516
7517<h5>Syntax:</h5>
7518<p>This is an overloaded intrinsic. You can use <tt>llvm.fabs</tt> on any
7519 floating point or vector of floating point type. Not all targets support all
7520 types however.</p>
7521
7522<pre>
7523 declare float @llvm.fabs.f32(float %Val)
7524 declare double @llvm.fabs.f64(double %Val)
7525 declare x86_fp80 @llvm.fabs.f80(x86_fp80 %Val)
7526 declare fp128 @llvm.fabs.f128(fp128 %Val)
7527 declare ppc_fp128 @llvm.fabs.ppcf128(ppc_fp128 %Val)
7528</pre>
7529
7530<h5>Overview:</h5>
7531<p>The '<tt>llvm.fabs.*</tt>' intrinsics return the absolute value of
7532 the operand.</p>
7533
7534<h5>Arguments:</h5>
7535<p>The argument and return value are floating point numbers of the same
7536 type.</p>
7537
7538<h5>Semantics:</h5>
7539<p>This function returns the same values as the libm <tt>fabs</tt> functions
7540 would, and handles error conditions in the same way.</p>
7541
7542</div>
7543
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7544</div>
7545
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7546<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7547<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7548 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7549</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7550
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7551<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7552
7553<p>LLVM provides intrinsics for a few important bit manipulation operations.
7554 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7555
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7556<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7557<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7558 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7559</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7560
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7561<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7562
7563<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7564<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7565 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7566
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7567<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7568 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7569 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7570 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +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.bswap</tt>' family of intrinsics is used to byte swap integer
7575 values with an even number of bytes (positive multiple of 16 bits). These
7576 are useful for performing operations on data that is not in the target's
7577 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7578
7579<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7580<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7581 and low byte of the input i16 swapped. Similarly,
7582 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7583 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7584 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7585 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7586 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7587 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7588
7589</div>
7590
7591<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7592<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7593 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7594</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7595
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7596<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7597
7598<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7599<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]7600 width, or on any vector with integer elements. Not all targets support all
7601 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7602
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7603<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7604 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7605 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7606 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7607 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7608 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7609 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]7610</pre>
7611
7612<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7613<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7614 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7615
7616<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7617<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]7618 integer type, or a vector with integer elements.
7619 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7620
7621<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7622<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7623 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7624
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7625</div>
7626
7627<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7628<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7629 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7630</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7631
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7632<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7633
7634<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7635<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]7636 integer bit width, or any vector whose elements are integers. Not all
7637 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7638
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7639<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7640 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7641 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7642 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7643 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7644 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7645 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]7646</pre>
7647
7648<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7649<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7650 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7651
7652<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7653<p>The first argument is the value to be counted. This argument may be of any
7654 integer type, or a vectory with integer element type. The return type
7655 must match the first argument type.</p>
7656
7657<p>The second argument must be a constant and is a flag to indicate whether the
7658 intrinsic should ensure that a zero as the first argument produces a defined
7659 result. Historically some architectures did not provide a defined result for
7660 zero values as efficiently, and many algorithms are now predicated on
7661 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7662
7663<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7664<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7665 zeros in a variable, or within each element of the vector.
7666 If <tt>src == 0</tt> then the result is the size in bits of the type of
7667 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7668 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7669
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7670</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7671
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7672<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7673<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7674 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7675</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7676
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7677<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7678
7679<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7680<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]7681 integer bit width, or any vector of integer elements. Not all targets
7682 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7683
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7684<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7685 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7686 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7687 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7688 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7689 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7690 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]7691</pre>
7692
7693<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7694<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7695 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7696
7697<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7698<p>The first argument is the value to be counted. This argument may be of any
7699 integer type, or a vectory with integer element type. The return type
7700 must match the first argument type.</p>
7701
7702<p>The second argument must be a constant and is a flag to indicate whether the
7703 intrinsic should ensure that a zero as the first argument produces a defined
7704 result. Historically some architectures did not provide a defined result for
7705 zero values as efficiently, and many algorithms are now predicated on
7706 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7707
7708<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7709<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7710 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7711 If <tt>src == 0</tt> then the result is the size in bits of the type of
7712 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7713 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7714
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7715</div>
7716
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7717</div>
7718
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7719<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7720<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7721 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7722</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7723
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7724<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7725
7726<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7727
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7728<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7729<h4>
7730 <a name="int_sadd_overflow">
7731 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7732 </a>
7733</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7734
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7735<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7736
7737<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7738<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]7739 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7740
7741<pre>
7742 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7743 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7744 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7745</pre>
7746
7747<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7748<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7749 a signed addition of the two arguments, and indicate whether an overflow
7750 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7751
7752<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7753<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]7754 be of integer types of any bit width, but they must have the same bit
7755 width. The second element of the result structure must be of
7756 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7757 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7758
7759<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7760<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7761 a signed addition of the two variables. They return a structure &mdash; the
7762 first element of which is the signed summation, and the second element of
7763 which is a bit specifying if the signed summation resulted in an
7764 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7765
7766<h5>Examples:</h5>
7767<pre>
7768 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7769 %sum = extractvalue {i32, i1} %res, 0
7770 %obit = extractvalue {i32, i1} %res, 1
7771 br i1 %obit, label %overflow, label %normal
7772</pre>
7773
7774</div>
7775
7776<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7777<h4>
7778 <a name="int_uadd_overflow">
7779 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7780 </a>
7781</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7782
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7783<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7784
7785<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7786<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]7787 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7788
7789<pre>
7790 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7791 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7792 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7793</pre>
7794
7795<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7796<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7797 an unsigned addition of the two arguments, and indicate whether a carry
7798 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7799
7800<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7801<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]7802 be of integer types of any bit width, but they must have the same bit
7803 width. The second element of the result structure must be of
7804 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7805 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7806
7807<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7808<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7809 an unsigned addition of the two arguments. They return a structure &mdash;
7810 the first element of which is the sum, and the second element of which is a
7811 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7812
7813<h5>Examples:</h5>
7814<pre>
7815 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7816 %sum = extractvalue {i32, i1} %res, 0
7817 %obit = extractvalue {i32, i1} %res, 1
7818 br i1 %obit, label %carry, label %normal
7819</pre>
7820
7821</div>
7822
7823<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7824<h4>
7825 <a name="int_ssub_overflow">
7826 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7827 </a>
7828</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7829
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7830<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7831
7832<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7833<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]7834 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7835
7836<pre>
7837 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7838 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7839 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7840</pre>
7841
7842<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7843<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7844 a signed subtraction of the two arguments, and indicate whether an overflow
7845 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7846
7847<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7848<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]7849 be of integer types of any bit width, but they must have the same bit
7850 width. The second element of the result structure must be of
7851 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7852 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7853
7854<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7855<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7856 a signed subtraction of the two arguments. They return a structure &mdash;
7857 the first element of which is the subtraction, and the second element of
7858 which is a bit specifying if the signed subtraction resulted in an
7859 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7860
7861<h5>Examples:</h5>
7862<pre>
7863 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7864 %sum = extractvalue {i32, i1} %res, 0
7865 %obit = extractvalue {i32, i1} %res, 1
7866 br i1 %obit, label %overflow, label %normal
7867</pre>
7868
7869</div>
7870
7871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7872<h4>
7873 <a name="int_usub_overflow">
7874 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7875 </a>
7876</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7878<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7879
7880<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7881<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]7882 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7883
7884<pre>
7885 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7886 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7887 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7888</pre>
7889
7890<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7891<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7892 an unsigned subtraction of the two arguments, and indicate whether an
7893 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7894
7895<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7896<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]7897 be of integer types of any bit width, but they must have the same bit
7898 width. The second element of the result structure must be of
7899 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7900 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7901
7902<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7903<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7904 an unsigned subtraction of the two arguments. They return a structure &mdash;
7905 the first element of which is the subtraction, and the second element of
7906 which is a bit specifying if the unsigned subtraction resulted in an
7907 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7908
7909<h5>Examples:</h5>
7910<pre>
7911 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7912 %sum = extractvalue {i32, i1} %res, 0
7913 %obit = extractvalue {i32, i1} %res, 1
7914 br i1 %obit, label %overflow, label %normal
7915</pre>
7916
7917</div>
7918
7919<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7920<h4>
7921 <a name="int_smul_overflow">
7922 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7923 </a>
7924</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7925
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7926<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7927
7928<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7929<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]7930 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7931
7932<pre>
7933 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7934 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7935 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7936</pre>
7937
7938<h5>Overview:</h5>
7939
7940<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7941 a signed multiplication of the two arguments, and indicate whether an
7942 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7943
7944<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7945<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]7946 be of integer types of any bit width, but they must have the same bit
7947 width. The second element of the result structure must be of
7948 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7949 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7950
7951<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7952<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7953 a signed multiplication of the two arguments. They return a structure &mdash;
7954 the first element of which is the multiplication, and the second element of
7955 which is a bit specifying if the signed multiplication resulted in an
7956 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7957
7958<h5>Examples:</h5>
7959<pre>
7960 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7961 %sum = extractvalue {i32, i1} %res, 0
7962 %obit = extractvalue {i32, i1} %res, 1
7963 br i1 %obit, label %overflow, label %normal
7964</pre>
7965
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7966</div>
7967
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7968<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7969<h4>
7970 <a name="int_umul_overflow">
7971 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7972 </a>
7973</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7974
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7975<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7976
7977<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7978<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]7979 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7980
7981<pre>
7982 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7983 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7984 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7985</pre>
7986
7987<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7988<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7989 a unsigned multiplication of the two arguments, and indicate whether an
7990 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7991
7992<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7993<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]7994 be of integer types of any bit width, but they must have the same bit
7995 width. The second element of the result structure must be of
7996 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7997 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7998
7999<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8000<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8001 an unsigned multiplication of the two arguments. They return a structure
8002 &mdash; the first element of which is the multiplication, and the second
8003 element of which is a bit specifying if the unsigned multiplication resulted
8004 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8005
8006<h5>Examples:</h5>
8007<pre>
8008 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
8009 %sum = extractvalue {i32, i1} %res, 0
8010 %obit = extractvalue {i32, i1} %res, 1
8011 br i1 %obit, label %overflow, label %normal
8012</pre>
8013
8014</div>
8015
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8016</div>
8017
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8018<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8019<h3>
Lang Hames5afba6f2012-06-05 19:07:46 +0000[diff] [blame]8020 <a name="spec_arithmetic">Specialised Arithmetic Intrinsics</a>
8021</h3>
8022
8023<!-- _______________________________________________________________________ -->
8024
8025<h4>
8026 <a name="fmuladd">'<tt>llvm.fmuladd.*</tt>' Intrinsic</a>
8027</h4>
8028
8029<div>
8030
8031<h5>Syntax:</h5>
8032<pre>
8033 declare float @llvm.fmuladd.f32(float %a, float %b, float %c)
8034 declare double @llvm.fmuladd.f64(double %a, double %b, double %c)
8035</pre>
8036
8037<h5>Overview:</h5>
8038<p>The '<tt>llvm.fmuladd.*</tt>' intrinsic functions represent multiply-add
8039expressions that can be fused if the code generator determines that the fused
8040expression would be legal and efficient.</p>
8041
8042<h5>Arguments:</h5>
8043<p>The '<tt>llvm.fmuladd.*</tt>' intrinsics each take three arguments: two
8044multiplicands, a and b, and an addend c.</p>
8045
8046<h5>Semantics:</h5>
8047<p>The expression:</p>
8048<pre>
8049 %0 = call float @llvm.fmuladd.f32(%a, %b, %c)
8050</pre>
8051<p>is equivalent to the expression a * b + c, except that rounding will not be
8052performed between the multiplication and addition steps if the code generator
8053fuses the operations. Fusion is not guaranteed, even if the target platform
8054supports it. If a fused multiply-add is required the corresponding llvm.fma.*
8055intrinsic function should be used instead.</p>
8056
8057<h5>Examples:</h5>
8058<pre>
8059 %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields {float}:r2 = (a * b) + c
8060</pre>
8061
8062</div>
8063
8064<!-- ======================================================================= -->
8065<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8066 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8067</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8068
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8069<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8070
Tobias Grosser057beb82012-05-24 15:59:06 +0000[diff] [blame]8071<p>For most target platforms, half precision floating point is a storage-only
8072 format. This means that it is
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8073 a dense encoding (in memory) but does not support computation in the
8074 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8075
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8076<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8077 value as an i16, then convert it to float with <a
8078 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
8079 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8080 double etc). To store the value back to memory, it is first converted to
8081 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8082 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
8083 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8084
8085<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8086<h4>
8087 <a name="int_convert_to_fp16">
8088 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
8089 </a>
8090</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8091
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8092<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8093
8094<h5>Syntax:</h5>
8095<pre>
8096 declare i16 @llvm.convert.to.fp16(f32 %a)
8097</pre>
8098
8099<h5>Overview:</h5>
8100<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8101 a conversion from single precision floating point format to half precision
8102 floating point format.</p>
8103
8104<h5>Arguments:</h5>
8105<p>The intrinsic function contains single argument - the value to be
8106 converted.</p>
8107
8108<h5>Semantics:</h5>
8109<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8110 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8111 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8112 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8113
8114<h5>Examples:</h5>
8115<pre>
8116 %res = call i16 @llvm.convert.to.fp16(f32 %a)
8117 store i16 %res, i16* @x, align 2
8118</pre>
8119
8120</div>
8121
8122<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8123<h4>
8124 <a name="int_convert_from_fp16">
8125 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8126 </a>
8127</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8128
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8129<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8130
8131<h5>Syntax:</h5>
8132<pre>
8133 declare f32 @llvm.convert.from.fp16(i16 %a)
8134</pre>
8135
8136<h5>Overview:</h5>
8137<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8138 a conversion from half precision floating point format to single precision
8139 floating point format.</p>
8140
8141<h5>Arguments:</h5>
8142<p>The intrinsic function contains single argument - the value to be
8143 converted.</p>
8144
8145<h5>Semantics:</h5>
8146<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8147 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8148 precision floating point format. The input half-float value is represented by
8149 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8150
8151<h5>Examples:</h5>
8152<pre>
8153 %a = load i16* @x, align 2
8154 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8155</pre>
8156
8157</div>
8158
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8159</div>
8160
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8161<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8162<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8163 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8164</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8165
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8166<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8167
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8168<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8169 prefix), are described in
8170 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8171 Level Debugging</a> document.</p>
8172
8173</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8174
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8175<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8176<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8177 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8178</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8179
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8180<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8181
8182<p>The LLVM exception handling intrinsics (which all start with
8183 <tt>llvm.eh.</tt> prefix), are described in
8184 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8185 Handling</a> document.</p>
8186
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8187</div>
8188
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8189<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8190<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8191 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8192</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8193
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8194<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8195
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8196<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]8197 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8198 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8199 function pointer lacking the nest parameter - the caller does not need to
8200 provide a value for it. Instead, the value to use is stored in advance in a
8201 "trampoline", a block of memory usually allocated on the stack, which also
8202 contains code to splice the nest value into the argument list. This is used
8203 to implement the GCC nested function address extension.</p>
8204
8205<p>For example, if the function is
8206 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8207 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8208 follows:</p>
8209
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]8210<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8211 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8212 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8213 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8214 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8215 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8216</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8217
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8218<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8219 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8220
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8221<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8222<h4>
8223 <a name="int_it">
8224 '<tt>llvm.init.trampoline</tt>' Intrinsic
8225 </a>
8226</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8227
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8228<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8229
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8230<h5>Syntax:</h5>
8231<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8232 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]8233</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8234
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8235<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8236<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8237 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8238
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8239<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8240<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8241 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8242 sufficiently aligned block of memory; this memory is written to by the
8243 intrinsic. Note that the size and the alignment are target-specific - LLVM
8244 currently provides no portable way of determining them, so a front-end that
8245 generates this intrinsic needs to have some target-specific knowledge.
8246 The <tt>func</tt> argument must hold a function bitcast to
8247 an <tt>i8*</tt>.</p>
8248
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8250<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]8251 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8252 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8253 which can be <a href="#int_trampoline">bitcast (to a new function) and
8254 called</a>. The new function's signature is the same as that of
8255 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8256 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8257 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8258 with the same argument list, but with <tt>nval</tt> used for the missing
8259 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8260 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8261 to the returned function pointer is undefined.</p>
8262</div>
8263
8264<!-- _______________________________________________________________________ -->
8265<h4>
8266 <a name="int_at">
8267 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8268 </a>
8269</h4>
8270
8271<div>
8272
8273<h5>Syntax:</h5>
8274<pre>
8275 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8276</pre>
8277
8278<h5>Overview:</h5>
8279<p>This performs any required machine-specific adjustment to the address of a
8280 trampoline (passed as <tt>tramp</tt>).</p>
8281
8282<h5>Arguments:</h5>
8283<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8284 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8285 </a>.</p>
8286
8287<h5>Semantics:</h5>
8288<p>On some architectures the address of the code to be executed needs to be
8289 different to the address where the trampoline is actually stored. This
8290 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8291 after performing the required machine specific adjustments.
8292 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8293 executed</a>.
8294</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8295
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8296</div>
8297
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8298</div>
8299
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8300<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8301<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8302 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8303</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8304
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8305<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8306
8307<p>This class of intrinsics exists to information about the lifetime of memory
8308 objects and ranges where variables are immutable.</p>
8309
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8310<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8311<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8312 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8313</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8314
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8315<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8316
8317<h5>Syntax:</h5>
8318<pre>
8319 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8320</pre>
8321
8322<h5>Overview:</h5>
8323<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8324 object's lifetime.</p>
8325
8326<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8327<p>The first argument is a constant integer representing the size of the
8328 object, or -1 if it is variable sized. The second argument is a pointer to
8329 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8330
8331<h5>Semantics:</h5>
8332<p>This intrinsic indicates that before this point in the code, the value of the
8333 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]8334 never be used and has an undefined value. A load from the pointer that
8335 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8336 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8337
8338</div>
8339
8340<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8341<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8342 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8343</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8344
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8345<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8346
8347<h5>Syntax:</h5>
8348<pre>
8349 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8350</pre>
8351
8352<h5>Overview:</h5>
8353<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8354 object's lifetime.</p>
8355
8356<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8357<p>The first argument is a constant integer representing the size of the
8358 object, or -1 if it is variable sized. The second argument is a pointer to
8359 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8360
8361<h5>Semantics:</h5>
8362<p>This intrinsic indicates that after this point in the code, the value of the
8363 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8364 never be used and has an undefined value. Any stores into the memory object
8365 following this intrinsic may be removed as dead.
8366
8367</div>
8368
8369<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8370<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8371 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8372</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8373
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8374<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8375
8376<h5>Syntax:</h5>
8377<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8378 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8379</pre>
8380
8381<h5>Overview:</h5>
8382<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8383 a memory object will not change.</p>
8384
8385<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8386<p>The first argument is a constant integer representing the size of the
8387 object, or -1 if it is variable sized. The second argument is a pointer to
8388 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8389
8390<h5>Semantics:</h5>
8391<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8392 the return value, the referenced memory location is constant and
8393 unchanging.</p>
8394
8395</div>
8396
8397<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8398<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8399 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8400</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8401
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8402<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8403
8404<h5>Syntax:</h5>
8405<pre>
8406 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8407</pre>
8408
8409<h5>Overview:</h5>
8410<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8411 a memory object are mutable.</p>
8412
8413<h5>Arguments:</h5>
8414<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8415 The second argument is a constant integer representing the size of the
8416 object, or -1 if it is variable sized and the third argument is a pointer
8417 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8418
8419<h5>Semantics:</h5>
8420<p>This intrinsic indicates that the memory is mutable again.</p>
8421
8422</div>
8423
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8424</div>
8425
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8426<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8427<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8428 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8429</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8431<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8432
8433<p>This class of intrinsics is designed to be generic and has no specific
8434 purpose.</p>
8435
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8436<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8437<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8438 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8439</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8440
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8441<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8442
8443<h5>Syntax:</h5>
8444<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8445 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]8446</pre>
8447
8448<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8449<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8450
8451<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8452<p>The first argument is a pointer to a value, the second is a pointer to a
8453 global string, the third is a pointer to a global string which is the source
8454 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8455
8456<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8457<p>This intrinsic allows annotation of local variables with arbitrary strings.
8458 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8459 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8460 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8461
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8462</div>
8463
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8464<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8465<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8466 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8467</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8468
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8469<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8470
8471<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8472<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8473 any integer bit width.</p>
8474
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8475<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8476 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8477 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8478 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8479 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8480 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]8481</pre>
8482
8483<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8484<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8485
8486<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8487<p>The first argument is an integer value (result of some expression), the
8488 second is a pointer to a global string, the third is a pointer to a global
8489 string which is the source file name, and the last argument is the line
8490 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8491
8492<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8493<p>This intrinsic allows annotations to be put on arbitrary expressions with
8494 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8495 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8496 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8497
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8498</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8499
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8500<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8501<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8502 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8503</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8504
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8505<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8506
8507<h5>Syntax:</h5>
8508<pre>
Chris Lattner86208902012-05-27 23:20:41 +0000[diff] [blame]8509 declare void @llvm.trap() noreturn nounwind
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8510</pre>
8511
8512<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8513<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8514
8515<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8516<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8517
8518<h5>Semantics:</h5>
John Criswell99534f32012-05-16 00:26:51 +0000[diff] [blame]8519<p>This intrinsic is lowered to the target dependent trap instruction. If the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8520 target does not have a trap instruction, this intrinsic will be lowered to
John Criswell99534f32012-05-16 00:26:51 +0000[diff] [blame]8521 a call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8522
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8523</div>
8524
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8525<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8526<h4>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]8527 <a name="int_debugtrap">'<tt>llvm.debugtrap</tt>' Intrinsic</a>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8528</h4>
8529
8530<div>
8531
8532<h5>Syntax:</h5>
8533<pre>
Chris Lattner86208902012-05-27 23:20:41 +0000[diff] [blame]8534 declare void @llvm.debugtrap() nounwind
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8535</pre>
8536
8537<h5>Overview:</h5>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]8538<p>The '<tt>llvm.debugtrap</tt>' intrinsic.</p>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8539
8540<h5>Arguments:</h5>
8541<p>None.</p>
8542
8543<h5>Semantics:</h5>
8544<p>This intrinsic is lowered to code which is intended to cause an execution
8545 trap with the intention of requesting the attention of a debugger.</p>
8546
8547</div>
8548
8549<!-- _______________________________________________________________________ -->
8550<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8551 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8552</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8553
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8554<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8555
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8556<h5>Syntax:</h5>
8557<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8558 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8559</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8560
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8561<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8562<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8563 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8564 ensure that it is placed on the stack before local variables.</p>
8565
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8566<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8567<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8568 arguments. The first argument is the value loaded from the stack
8569 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8570 that has enough space to hold the value of the guard.</p>
8571
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8572<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8573<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8574 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8575 stack. This is to ensure that if a local variable on the stack is
8576 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8577 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8578 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8579 function.</p>
8580
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8581</div>
8582
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8583<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8584<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8585 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8586</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8587
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8588<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8589
8590<h5>Syntax:</h5>
8591<pre>
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8592 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;)
8593 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8594</pre>
8595
8596<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8597<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8598 the optimizers to determine at compile time whether a) an operation (like
8599 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8600 runtime check for overflow isn't necessary. An object in this context means
8601 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8602
8603<h5>Arguments:</h5>
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8604<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8605 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8606 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if
8607 true) or -1 (if false) when the object size is unknown.
8608 The second argument only accepts constants.</p>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8609
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8610<h5>Semantics:</h5>
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8611<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8612 the size of the object concerned. If the size cannot be determined at compile
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8613 time, <tt>llvm.objectsize</tt> returns <tt>i32/i64 -1 or 0</tt>
8614 (depending on the <tt>min</tt> argument).</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8615
8616</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8617<!-- _______________________________________________________________________ -->
8618<h4>
8619 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8620</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8621
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8622<div>
8623
8624<h5>Syntax:</h5>
8625<pre>
8626 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8627 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8628</pre>
8629
8630<h5>Overview:</h5>
8631<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8632 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8633
8634<h5>Arguments:</h5>
8635<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8636 argument is a value. The second argument is an expected value, this needs to
8637 be a constant value, variables are not allowed.</p>
8638
8639<h5>Semantics:</h5>
8640<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8641</div>
8642
8643</div>
8644
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8645</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8646<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8647<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8648<address>
8649 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8650 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8651 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8652 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]8653
8654 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8655 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8656 Last modified: $Date$
8657</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8658
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8659</body>
8660</html>