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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / e660fc15fe1f1b8a19488f39d0ec09acc79bed0d / . / 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 Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling32811be2012-08-17 18:33:14 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr_auto_hide">'<tt>linkonce_odr_auto_hide</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>
Dan Gohman273a92e2012-09-21 18:21:48 +0000[diff] [blame]106 <li><a href="#tbaa.struct">'<tt>tbaa.struct</tt>' Metadata</a></li>
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]107 <li><a href="#fpmath">'<tt>fpmath</tt>' Metadata</a></li>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]108 <li><a href="#range">'<tt>range</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]111 </ol>
112 </li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]113 <li><a href="#module_flags">Module Flags Metadata</a>
114 <ol>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]115 <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]116 </ol>
117 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]118 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
119 <ol>
120 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]121 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
122 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]123 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
124 Global Variable</a></li>
125 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
126 Global Variable</a></li>
127 </ol>
128 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#instref">Instruction Reference</a>
130 <ol>
131 <li><a href="#terminators">Terminator Instructions</a>
132 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
134 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]135 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]136 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]137 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]138 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]139 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 </ol>
141 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 <li><a href="#binaryops">Binary Operations</a>
143 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]145 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]146 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]147 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]149 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]150 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
151 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
152 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]153 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
154 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
155 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]156 </ol>
157 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]158 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
159 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]160 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
161 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
162 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]163 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]164 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]165 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]166 </ol>
167 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]168 <li><a href="#vectorops">Vector Operations</a>
169 <ol>
170 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
171 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
172 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]173 </ol>
174 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]175 <li><a href="#aggregateops">Aggregate Operations</a>
176 <ol>
177 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
178 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
179 </ol>
180 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]181 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]182 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]183 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
184 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
185 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
186 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
187 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
188 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]189 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]190 </ol>
191 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]192 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]193 <ol>
194 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
195 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
198 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]199 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
200 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
201 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
202 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]203 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
204 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]205 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]206 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]207 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]208 <li><a href="#otherops">Other Operations</a>
209 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]210 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
211 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]213 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]215 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]216 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]217 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]218 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]219 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]220 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]221 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]222 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]223 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
224 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]225 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
226 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
227 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]230 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
231 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
233 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
234 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]235 </ol>
236 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]237 <li><a href="#int_codegen">Code Generator Intrinsics</a>
238 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]239 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
240 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
241 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
242 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
243 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
244 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]245 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]246 </ol>
247 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]248 <li><a href="#int_libc">Standard C Library Intrinsics</a>
249 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]250 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
252 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
254 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]255 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
257 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]258 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
259 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]260 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Peter Collingbourne168a4c32012-07-03 12:25:40 +0000[diff] [blame]261 <li><a href="#int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a></li>
Dan Gohman27db99f2012-07-26 17:43:27 +0000[diff] [blame]262 <li><a href="#int_floor">'<tt>llvm.floor.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]263 </ol>
264 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]265 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]266 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]267 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]268 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
269 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
270 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]273 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
274 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]275 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
276 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
277 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
278 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
279 <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]280 <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]281 </ol>
282 </li>
Lang Hames5afba6f2012-06-05 19:07:46 +0000[diff] [blame]283 <li><a href="#spec_arithmetic">Specialised Arithmetic Intrinsics</a>
284 <ol>
285 <li><a href="#fmuladd">'<tt>llvm.fmuladd</tt> Intrinsic</a></li>
286 </ol>
287 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]288 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
289 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]290 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
291 <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]292 </ol>
293 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]294 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]295 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]296 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]297 <ol>
298 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]299 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]300 </ol>
301 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]302 <li><a href="#int_memorymarkers">Memory Use Markers</a>
303 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]304 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
305 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
306 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
307 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]308 </ol>
309 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]310 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]311 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]312 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]313 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]314 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]315 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]316 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]317 '<tt>llvm.trap</tt>' Intrinsic</a></li>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]318 <li><a href="#int_debugtrap">
319 '<tt>llvm.debugtrap</tt>' Intrinsic</a></li>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]320 <li><a href="#int_stackprotector">
321 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Nuno Lopesb0c76d72012-07-05 17:37:07 +0000[diff] [blame]322 <li><a href="#int_objectsize">
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]323 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Nuno Lopesb0c76d72012-07-05 17:37:07 +0000[diff] [blame]324 <li><a href="#int_expect">
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]325 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Nuno Lopesb0c76d72012-07-05 17:37:07 +0000[diff] [blame]326 <li><a href="#int_donothing">
327 '<tt>llvm.donothing</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]328 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]329 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]330 </ol>
331 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]332</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
334<div class="doc_author">
335 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
336 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]337</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]339<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]340<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]341<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]343<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]344
345<p>This document is a reference manual for the LLVM assembly language. LLVM is
346 a Static Single Assignment (SSA) based representation that provides type
347 safety, low-level operations, flexibility, and the capability of representing
348 'all' high-level languages cleanly. It is the common code representation
349 used throughout all phases of the LLVM compilation strategy.</p>
350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]351</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]352
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]353<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]354<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]355<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]356
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]357<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]358
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359<p>The LLVM code representation is designed to be used in three different forms:
360 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
361 for fast loading by a Just-In-Time compiler), and as a human readable
362 assembly language representation. This allows LLVM to provide a powerful
363 intermediate representation for efficient compiler transformations and
364 analysis, while providing a natural means to debug and visualize the
365 transformations. The three different forms of LLVM are all equivalent. This
366 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368<p>The LLVM representation aims to be light-weight and low-level while being
369 expressive, typed, and extensible at the same time. It aims to be a
370 "universal IR" of sorts, by being at a low enough level that high-level ideas
371 may be cleanly mapped to it (similar to how microprocessors are "universal
372 IR's", allowing many source languages to be mapped to them). By providing
373 type information, LLVM can be used as the target of optimizations: for
374 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]375 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]376 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]378<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]379<h4>
380 <a name="wellformed">Well-Formedness</a>
381</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]382
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]383<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]384
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]385<p>It is important to note that this document describes 'well formed' LLVM
386 assembly language. There is a difference between what the parser accepts and
387 what is considered 'well formed'. For example, the following instruction is
388 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]390<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]391%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392</pre>
393
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]394<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
395 LLVM infrastructure provides a verification pass that may be used to verify
396 that an LLVM module is well formed. This pass is automatically run by the
397 parser after parsing input assembly and by the optimizer before it outputs
398 bitcode. The violations pointed out by the verifier pass indicate bugs in
399 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]400
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]401</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]402
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]403</div>
404
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]405<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]407<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]408<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]409<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]410
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]411<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]412
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413<p>LLVM identifiers come in two basic types: global and local. Global
414 identifiers (functions, global variables) begin with the <tt>'@'</tt>
415 character. Local identifiers (register names, types) begin with
416 the <tt>'%'</tt> character. Additionally, there are three different formats
417 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]419<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]420 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]421 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
422 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
423 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
424 other characters in their names can be surrounded with quotes. Special
425 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
426 ASCII code for the character in hexadecimal. In this way, any character
427 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]429 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]430 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]432 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]433 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]434</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]436<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]437 don't need to worry about name clashes with reserved words, and the set of
438 reserved words may be expanded in the future without penalty. Additionally,
439 unnamed identifiers allow a compiler to quickly come up with a temporary
440 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]442<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]443 languages. There are keywords for different opcodes
444 ('<tt><a href="#i_add">add</a></tt>',
445 '<tt><a href="#i_bitcast">bitcast</a></tt>',
446 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
447 ('<tt><a href="#t_void">void</a></tt>',
448 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
449 reserved words cannot conflict with variable names, because none of them
450 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
452<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]453 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]455<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]457<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]458%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459</pre>
460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]461<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]463<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]464%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465</pre>
466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]469<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]470%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
471%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]472%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473</pre>
474
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]475<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
476 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]478<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]479 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]480 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
482 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]483 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]484
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]485 <li>Unnamed temporaries are numbered sequentially</li>
486</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]487
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]488<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]489 demonstrating instructions, we will follow an instruction with a comment that
490 defines the type and name of value produced. Comments are shown in italic
491 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]492
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]493</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]494
495<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]496<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]498<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]500<h3>
501 <a name="modulestructure">Module Structure</a>
502</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]503
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]504<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]506<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
507 translation unit of the input programs. Each module consists of functions,
508 global variables, and symbol table entries. Modules may be combined together
509 with the LLVM linker, which merges function (and global variable)
510 definitions, resolves forward declarations, and merges symbol table
511 entries. Here is an example of the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]512
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]513<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]514<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]515<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]516
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]517<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]518<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]519
520<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]521define i32 @main() { <i>; i32()* </i>&nbsp;
522 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]523 %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]524
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]525 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]526 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]527 <a href="#i_ret">ret</a> i32 0&nbsp;
528}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]529
530<i>; Named metadata</i>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]531!1 = metadata !{i32 42}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]532!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]533</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]535<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]536 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]538 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]539 "<tt>foo</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]540
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]541<p>In general, a module is made up of a list of global values (where both
542 functions and global variables are global values). Global values are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]543 represented by a pointer to a memory location (in this case, a pointer to an
544 array of char, and a pointer to a function), and have one of the
545 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]546
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]547</div>
548
549<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]550<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]551 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]552</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]553
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]554<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]555
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]556<p>All Global Variables and Functions have one of the following types of
557 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]558
559<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]561 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
562 by objects in the current module. In particular, linking code into a
563 module with an private global value may cause the private to be renamed as
564 necessary to avoid collisions. Because the symbol is private to the
565 module, all references can be updated. This doesn't show up in any symbol
566 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]567
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]568 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]569 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
570 assembler and evaluated by the linker. Unlike normal strong symbols, they
571 are removed by the linker from the final linked image (executable or
572 dynamic library).</dd>
573
574 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
575 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
576 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
577 linker. The symbols are removed by the linker from the final linked image
578 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]579
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]580 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]581 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]582 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
583 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]584
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]586 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]587 into the object file corresponding to the LLVM module. They exist to
588 allow inlining and other optimizations to take place given knowledge of
589 the definition of the global, which is known to be somewhere outside the
590 module. Globals with <tt>available_externally</tt> linkage are allowed to
591 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
592 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]593
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]595 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]596 the same name when linkage occurs. This can be used to implement
597 some forms of inline functions, templates, or other code which must be
598 generated in each translation unit that uses it, but where the body may
599 be overridden with a more definitive definition later. Unreferenced
600 <tt>linkonce</tt> globals are allowed to be discarded. Note that
601 <tt>linkonce</tt> linkage does not actually allow the optimizer to
602 inline the body of this function into callers because it doesn't know if
603 this definition of the function is the definitive definition within the
604 program or whether it will be overridden by a stronger definition.
605 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
606 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]607
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]608 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]609 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
610 <tt>linkonce</tt> linkage, except that unreferenced globals with
611 <tt>weak</tt> linkage may not be discarded. This is used for globals that
612 are declared "weak" in C source code.</dd>
613
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]614 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]615 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
616 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
617 global scope.
618 Symbols with "<tt>common</tt>" linkage are merged in the same way as
619 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]620 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]621 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]622 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
623 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]624
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]625
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]626 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]627 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]628 pointer to array type. When two global variables with appending linkage
629 are linked together, the two global arrays are appended together. This is
630 the LLVM, typesafe, equivalent of having the system linker append together
631 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]632
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]633 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 <dd>The semantics of this linkage follow the ELF object file model: the symbol
635 is weak until linked, if not linked, the symbol becomes null instead of
636 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]637
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
639 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 <dd>Some languages allow differing globals to be merged, such as two functions
641 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]642 that only equivalent globals are ever merged (the "one definition rule"
643 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644 and <tt>weak_odr</tt> linkage types to indicate that the global will only
645 be merged with equivalent globals. These linkage types are otherwise the
646 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]647
Bill Wendling32811be2012-08-17 18:33:14 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_linkonce_odr_auto_hide">linkonce_odr_auto_hide</a></b></tt></dt>
649 <dd>Similar to "<tt>linkonce_odr</tt>", but nothing in the translation unit
650 takes the address of this definition. For instance, functions that had an
651 inline definition, but the compiler decided not to inline it.
652 <tt>linkonce_odr_auto_hide</tt> may have only <tt>default</tt> visibility.
653 The symbols are removed by the linker from the final linked image
654 (executable or dynamic library).</dd>
655
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]657 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 visible, meaning that it participates in linkage and can be used to
659 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]660</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]661
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]662<p>The next two types of linkage are targeted for Microsoft Windows platform
663 only. They are designed to support importing (exporting) symbols from (to)
664 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]665
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]666<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]667 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]668 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669 or variable via a global pointer to a pointer that is set up by the DLL
670 exporting the symbol. On Microsoft Windows targets, the pointer name is
671 formed by combining <code>__imp_</code> and the function or variable
672 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]673
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]674 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]675 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]676 pointer to a pointer in a DLL, so that it can be referenced with the
677 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
678 name is formed by combining <code>__imp_</code> and the function or
679 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]680</dl>
681
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]682<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
683 another module defined a "<tt>.LC0</tt>" variable and was linked with this
684 one, one of the two would be renamed, preventing a collision. Since
685 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
686 declarations), they are accessible outside of the current module.</p>
687
688<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]689 other than <tt>external</tt>, <tt>dllimport</tt>
690 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]691
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]692<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]693 or <tt>weak_odr</tt> linkages.</p>
694
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]695</div>
696
697<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]698<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]700</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]702<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]703
704<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]705 and <a href="#i_invoke">invokes</a> can all have an optional calling
706 convention specified for the call. The calling convention of any pair of
707 dynamic caller/callee must match, or the behavior of the program is
708 undefined. The following calling conventions are supported by LLVM, and more
709 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]710
711<dl>
712 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 specified) matches the target C calling conventions. This calling
715 convention supports varargs function calls and tolerates some mismatch in
716 the declared prototype and implemented declaration of the function (as
717 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718
719 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]720 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]721 (e.g. by passing things in registers). This calling convention allows the
722 target to use whatever tricks it wants to produce fast code for the
723 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]724 (Application Binary Interface).
725 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]726 when this or the GHC convention is used.</a> This calling convention
727 does not support varargs and requires the prototype of all callees to
728 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]729
730 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]731 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]732 as possible under the assumption that the call is not commonly executed.
733 As such, these calls often preserve all registers so that the call does
734 not break any live ranges in the caller side. This calling convention
735 does not support varargs and requires the prototype of all callees to
736 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]737
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]738 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
739 <dd>This calling convention has been implemented specifically for use by the
740 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
741 It passes everything in registers, going to extremes to achieve this by
742 disabling callee save registers. This calling convention should not be
743 used lightly but only for specific situations such as an alternative to
744 the <em>register pinning</em> performance technique often used when
745 implementing functional programming languages.At the moment only X86
746 supports this convention and it has the following limitations:
747 <ul>
748 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
749 floating point types are supported.</li>
750 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
751 6 floating point parameters.</li>
752 </ul>
753 This calling convention supports
754 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
755 requires both the caller and callee are using it.
756 </dd>
757
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]758 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]759 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]760 target-specific calling conventions to be used. Target specific calling
761 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]762</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]763
764<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 support Pascal conventions or any other well-known target-independent
766 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]767
768</div>
769
770<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]771<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]772 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]773</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]774
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]775<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]777<p>All Global Variables and Functions have one of the following visibility
778 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]779
780<dl>
781 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]782 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]783 that the declaration is visible to other modules and, in shared libraries,
784 means that the declared entity may be overridden. On Darwin, default
785 visibility means that the declaration is visible to other modules. Default
786 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]787
788 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]789 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]790 object if they are in the same shared object. Usually, hidden visibility
791 indicates that the symbol will not be placed into the dynamic symbol
792 table, so no other module (executable or shared library) can reference it
793 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]794
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]795 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]796 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]797 the dynamic symbol table, but that references within the defining module
798 will bind to the local symbol. That is, the symbol cannot be overridden by
799 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]800</dl>
801
802</div>
803
804<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]805<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]806 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]807</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]808
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]809<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]810
811<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]812 it easier to read the IR and make the IR more condensed (particularly when
813 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]815<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]816%mytype = type { %mytype*, i32 }
817</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]818
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]819<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]820 "<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]821 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]822
823<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]824 and that you can therefore specify multiple names for the same type. This
825 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
826 uses structural typing, the name is not part of the type. When printing out
827 LLVM IR, the printer will pick <em>one name</em> to render all types of a
828 particular shape. This means that if you have code where two different
829 source types end up having the same LLVM type, that the dumper will sometimes
830 print the "wrong" or unexpected type. This is an important design point and
831 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]832
833</div>
834
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]835<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]836<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]837 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]838</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]839
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]840<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]841
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]842<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843 instead of run-time. Global variables may optionally be initialized, may
844 have an explicit section to be placed in, and may have an optional explicit
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame]845 alignment specified.</p>
846
847<p>A variable may be defined as <tt>thread_local</tt>, which
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]848 means that it will not be shared by threads (each thread will have a
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame]849 separated copy of the variable). Not all targets support thread-local
850 variables. Optionally, a TLS model may be specified:</p>
851
852<dl>
853 <dt><b><tt>localdynamic</tt></b>:</dt>
854 <dd>For variables that are only used within the current shared library.</dd>
855
856 <dt><b><tt>initialexec</tt></b>:</dt>
857 <dd>For variables in modules that will not be loaded dynamically.</dd>
858
859 <dt><b><tt>localexec</tt></b>:</dt>
860 <dd>For variables defined in the executable and only used within it.</dd>
861</dl>
862
863<p>The models correspond to the ELF TLS models; see
864 <a href="http://people.redhat.com/drepper/tls.pdf">ELF
865 Handling For Thread-Local Storage</a> for more information on under which
866 circumstances the different models may be used. The target may choose a
867 different TLS model if the specified model is not supported, or if a better
868 choice of model can be made.</p>
869
870<p>A variable may be defined as a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]871 "constant," which indicates that the contents of the variable
872 will <b>never</b> be modified (enabling better optimization, allowing the
873 global data to be placed in the read-only section of an executable, etc).
874 Note that variables that need runtime initialization cannot be marked
875 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]876
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]877<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
878 constant, even if the final definition of the global is not. This capability
879 can be used to enable slightly better optimization of the program, but
880 requires the language definition to guarantee that optimizations based on the
881 'constantness' are valid for the translation units that do not include the
882 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]883
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]884<p>As SSA values, global variables define pointer values that are in scope
885 (i.e. they dominate) all basic blocks in the program. Global variables
886 always define a pointer to their "content" type because they describe a
887 region of memory, and all memory objects in LLVM are accessed through
888 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]890<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
891 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]892 like this can be merged with other constants if they have the same
893 initializer. Note that a constant with significant address <em>can</em>
894 be merged with a <tt>unnamed_addr</tt> constant, the result being a
895 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]896
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897<p>A global variable may be declared to reside in a target-specific numbered
898 address space. For targets that support them, address spaces may affect how
899 optimizations are performed and/or what target instructions are used to
900 access the variable. The default address space is zero. The address space
901 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]902
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]903<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]905
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]906<p>An explicit alignment may be specified for a global, which must be a power
907 of 2. If not present, or if the alignment is set to zero, the alignment of
908 the global is set by the target to whatever it feels convenient. If an
909 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]910 alignment. Targets and optimizers are not allowed to over-align the global
911 if the global has an assigned section. In this case, the extra alignment
912 could be observable: for example, code could assume that the globals are
913 densely packed in their section and try to iterate over them as an array,
914 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]915
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]916<p>For example, the following defines a global in a numbered address space with
917 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]918
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]919<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]920@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]921</pre>
922
Hans Wennborgce718ff2012-06-23 11:37:03 +0000[diff] [blame]923<p>The following example defines a thread-local global with
924 the <tt>initialexec</tt> TLS model:</p>
925
926<pre class="doc_code">
927@G = thread_local(initialexec) global i32 0, align 4
928</pre>
929
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]930</div>
931
932
933<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]934<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]935 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]936</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]937
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]938<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]939
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]940<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941 optional <a href="#linkage">linkage type</a>, an optional
942 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]943 <a href="#callingconv">calling convention</a>,
944 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]945 <a href="#paramattrs">parameter attribute</a> for the return type, a function
946 name, a (possibly empty) argument list (each with optional
947 <a href="#paramattrs">parameter attributes</a>), optional
948 <a href="#fnattrs">function attributes</a>, an optional section, an optional
949 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
950 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]952<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
953 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]954 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]955 <a href="#callingconv">calling convention</a>,
956 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]957 <a href="#paramattrs">parameter attribute</a> for the return type, a function
958 name, a possibly empty list of arguments, an optional alignment, and an
959 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]960
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]961<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]962 (Control Flow Graph) for the function. Each basic block may optionally start
963 with a label (giving the basic block a symbol table entry), contains a list
964 of instructions, and ends with a <a href="#terminators">terminator</a>
965 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]966
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]967<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]968 executed on entrance to the function, and it is not allowed to have
969 predecessor basic blocks (i.e. there can not be any branches to the entry
970 block of a function). Because the block can have no predecessors, it also
971 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]972
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]973<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]974 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]975
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]976<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]977 the alignment is set to zero, the alignment of the function is set by the
978 target to whatever it feels convenient. If an explicit alignment is
979 specified, the function is forced to have at least that much alignment. All
980 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]981
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]982<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]983 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]984
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]985<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]986<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]987define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]988 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
989 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
990 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
991 [<a href="#gc">gc</a>] { ... }
992</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]993
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]994</div>
995
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]996<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]997<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]998 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]999</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1001<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1002
1003<p>Aliases act as "second name" for the aliasee value (which can be either
1004 function, global variable, another alias or bitcast of global value). Aliases
1005 may have an optional <a href="#linkage">linkage type</a>, and an
1006 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]1007
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1008<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1009<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]1010@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]1011</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]1012
1013</div>
1014
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1015<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1016<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1017 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1018</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1019
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1020<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1021
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]1022<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1023 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]1024 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1025
1026<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1027<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1028; Some unnamed metadata nodes, which are referenced by the named metadata.
1029!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1030!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1031!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]1032; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]1033!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1034</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]1035
1036</div>
1037
1038<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1039<h3>
1040 <a name="paramattrs">Parameter Attributes</a>
1041</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1042
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1043<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1044
1045<p>The return type and each parameter of a function type may have a set of
1046 <i>parameter attributes</i> associated with them. Parameter attributes are
1047 used to communicate additional information about the result or parameters of
1048 a function. Parameter attributes are considered to be part of the function,
1049 not of the function type, so functions with different parameter attributes
1050 can have the same function type.</p>
1051
1052<p>Parameter attributes are simple keywords that follow the type specified. If
1053 multiple parameter attributes are needed, they are space separated. For
1054 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1055
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1056<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1057declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1058declare i32 @atoi(i8 zeroext)
1059declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1060</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1061
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1062<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1063 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1064
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1065<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1066
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1067<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1068 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1070 should be zero-extended to the extent required by the target's ABI (which
1071 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1072 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1073
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1074 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1075 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1076 should be sign-extended to the extent required by the target's ABI (which
1077 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1078 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1079
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1080 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1081 <dd>This indicates that this parameter or return value should be treated in a
1082 special target-dependent fashion during while emitting code for a function
1083 call or return (usually, by putting it in a register as opposed to memory,
1084 though some targets use it to distinguish between two different kinds of
1085 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1086
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1087 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1088 <dd><p>This indicates that the pointer parameter should really be passed by
1089 value to the function. The attribute implies that a hidden copy of the
1090 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1091 is made between the caller and the callee, so the callee is unable to
Chris Lattneref097052012-05-30 00:40:23 +0000[diff] [blame]1092 modify the value in the caller. This attribute is only valid on LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093 pointer arguments. It is generally used to pass structs and arrays by
1094 value, but is also valid on pointers to scalars. The copy is considered
1095 to belong to the caller not the callee (for example,
1096 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1097 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1098 values.</p>
1099
1100 <p>The byval attribute also supports specifying an alignment with
1101 the align attribute. It indicates the alignment of the stack slot to
1102 form and the known alignment of the pointer specified to the call site. If
1103 the alignment is not specified, then the code generator makes a
1104 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1105
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1106 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This indicates that the pointer parameter specifies the address of a
1108 structure that is the return value of the function in the source program.
1109 This pointer must be guaranteed by the caller to be valid: loads and
1110 stores to the structure may be assumed by the callee to not to trap. This
1111 may only be applied to the first parameter. This is not a valid attribute
1112 for return values. </dd>
1113
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1114 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1115 <dd>This indicates that pointer values
1116 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1117 value do not alias pointer values which are not <i>based</i> on it,
1118 ignoring certain "irrelevant" dependencies.
1119 For a call to the parent function, dependencies between memory
1120 references from before or after the call and from those during the call
1121 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1122 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1123 The caller shares the responsibility with the callee for ensuring that
1124 these requirements are met.
1125 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1126 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1127<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1128 Note that this definition of <tt>noalias</tt> is intentionally
1129 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1130 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1131<br>
1132 For function return values, C99's <tt>restrict</tt> is not meaningful,
1133 while LLVM's <tt>noalias</tt> is.
1134 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1135
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1136 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1137 <dd>This indicates that the callee does not make any copies of the pointer
1138 that outlive the callee itself. This is not a valid attribute for return
1139 values.</dd>
1140
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1141 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1142 <dd>This indicates that the pointer parameter can be excised using the
1143 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1144 attribute for return values.</dd>
1145</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1146
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1147</div>
1148
1149<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1150<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1151 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1152</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1153
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1154<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1155
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1156<p>Each function may specify a garbage collector name, which is simply a
1157 string:</p>
1158
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1159<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1162
1163<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1164 collector which will cause the compiler to alter its output in order to
1165 support the named garbage collection algorithm.</p>
1166
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1167</div>
1168
1169<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1170<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1171 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1172</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1173
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1174<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1175
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1176<p>Function attributes are set to communicate additional information about a
1177 function. Function attributes are considered to be part of the function, not
1178 of the function type, so functions with different parameter attributes can
1179 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1180
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1181<p>Function attributes are simple keywords that follow the type specified. If
1182 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1183
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1184<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1185define void @f() noinline { ... }
1186define void @f() alwaysinline { ... }
1187define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1188define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1189</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1190
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1191<dl>
Kostya Serebryany164b86b2012-01-20 17:56:17 +0000[diff] [blame]1192 <dt><tt><b>address_safety</b></tt></dt>
1193 <dd>This attribute indicates that the address safety analysis
1194 is enabled for this function. </dd>
1195
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1196 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1197 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1198 the backend should forcibly align the stack pointer. Specify the
1199 desired alignment, which must be a power of two, in parentheses.
1200
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1201 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1202 <dd>This attribute indicates that the inliner should attempt to inline this
1203 function into callers whenever possible, ignoring any active inlining size
1204 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1205
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1206 <dt><tt><b>nonlazybind</b></tt></dt>
1207 <dd>This attribute suppresses lazy symbol binding for the function. This
1208 may make calls to the function faster, at the cost of extra program
1209 startup time if the function is not called during program startup.</dd>
1210
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1211 <dt><tt><b>inlinehint</b></tt></dt>
1212 <dd>This attribute indicates that the source code contained a hint that inlining
1213 this function is desirable (such as the "inline" keyword in C/C++). It
1214 is just a hint; it imposes no requirements on the inliner.</dd>
1215
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1216 <dt><tt><b>naked</b></tt></dt>
1217 <dd>This attribute disables prologue / epilogue emission for the function.
1218 This can have very system-specific consequences.</dd>
1219
1220 <dt><tt><b>noimplicitfloat</b></tt></dt>
1221 <dd>This attributes disables implicit floating point instructions.</dd>
1222
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1223 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1224 <dd>This attribute indicates that the inliner should never inline this
1225 function in any situation. This attribute may not be used together with
1226 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1227
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1228 <dt><tt><b>noredzone</b></tt></dt>
1229 <dd>This attribute indicates that the code generator should not use a red
1230 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1231
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1232 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1233 <dd>This function attribute indicates that the function never returns
1234 normally. This produces undefined behavior at runtime if the function
1235 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1236
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1237 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1238 <dd>This function attribute indicates that the function never returns with an
1239 unwind or exceptional control flow. If the function does unwind, its
1240 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1241
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1242 <dt><tt><b>optsize</b></tt></dt>
1243 <dd>This attribute suggests that optimization passes and code generator passes
1244 make choices that keep the code size of this function low, and otherwise
1245 do optimizations specifically to reduce code size.</dd>
1246
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1247 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248 <dd>This attribute indicates that the function computes its result (or decides
1249 to unwind an exception) based strictly on its arguments, without
1250 dereferencing any pointer arguments or otherwise accessing any mutable
1251 state (e.g. memory, control registers, etc) visible to caller functions.
1252 It does not write through any pointer arguments
1253 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1254 changes any state visible to callers. This means that it cannot unwind
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1255 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1256
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1257 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1258 <dd>This attribute indicates that the function does not write through any
1259 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1260 arguments) or otherwise modify any state (e.g. memory, control registers,
1261 etc) visible to caller functions. It may dereference pointer arguments
1262 and read state that may be set in the caller. A readonly function always
1263 returns the same value (or unwinds an exception identically) when called
1264 with the same set of arguments and global state. It cannot unwind an
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1265 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1266
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1267 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1268 <dd>This attribute indicates that this function can return twice. The
1269 C <code>setjmp</code> is an example of such a function. The compiler
1270 disables some optimizations (like tail calls) in the caller of these
1271 functions.</dd>
1272
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1273 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274 <dd>This attribute indicates that the function should emit a stack smashing
1275 protector. It is in the form of a "canary"&mdash;a random value placed on
1276 the stack before the local variables that's checked upon return from the
1277 function to see if it has been overwritten. A heuristic is used to
1278 determine if a function needs stack protectors or not.<br>
1279<br>
1280 If a function that has an <tt>ssp</tt> attribute is inlined into a
1281 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1282 function will have an <tt>ssp</tt> attribute.</dd>
1283
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1284 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1285 <dd>This attribute indicates that the function should <em>always</em> emit a
1286 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1287 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1288<br>
1289 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1290 function that doesn't have an <tt>sspreq</tt> attribute or which has
1291 an <tt>ssp</tt> attribute, then the resulting function will have
1292 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1293
1294 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1295 <dd>This attribute indicates that the ABI being targeted requires that
1296 an unwind table entry be produce for this function even if we can
1297 show that no exceptions passes by it. This is normally the case for
1298 the ELF x86-64 abi, but it can be disabled for some compilation
1299 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1300</dl>
1301
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1302</div>
1303
1304<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1305<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1306 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1307</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1308
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1309<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1310
1311<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1312 the GCC "file scope inline asm" blocks. These blocks are internally
1313 concatenated by LLVM and treated as a single unit, but may be separated in
1314 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1315
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1316<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1317module asm "inline asm code goes here"
1318module asm "more can go here"
1319</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1320
1321<p>The strings can contain any character by escaping non-printable characters.
1322 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]1323 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1325<p>The inline asm code is simply printed to the machine code .s file when
1326 assembly code is generated.</p>
1327
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1328</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1329
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1331<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1332 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1333</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1335<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1336
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1337<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338 data is to be laid out in memory. The syntax for the data layout is
1339 simply:</p>
1340
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1341<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1342target datalayout = "<i>layout specification</i>"
1343</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1344
1345<p>The <i>layout specification</i> consists of a list of specifications
1346 separated by the minus sign character ('-'). Each specification starts with
1347 a letter and may include other information after the letter to define some
1348 aspect of the data layout. The specifications accepted are as follows:</p>
1349
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1350<dl>
1351 <dt><tt>E</tt></dt>
1352 <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]1353 bits with the most significance have the lowest address location.</dd>
1354
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1355 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1356 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1357 the bits with the least significance have the lowest address
1358 location.</dd>
1359
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1360 <dt><tt>S<i>size</i></tt></dt>
1361 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1362 of stack variables is limited to the natural stack alignment to avoid
1363 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1364 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1365 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1366
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1367 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1368 <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]1369 <i>preferred</i> alignments. All sizes are in bits. Specifying
1370 the <i>pref</i> alignment is optional. If omitted, the
1371 preceding <tt>:</tt> should be omitted too.</dd>
1372
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1373 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1374 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1375 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1376
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1377 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1378 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1379 <i>size</i>.</dd>
1380
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1381 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1382 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1383 <i>size</i>. Only values of <i>size</i> that are supported by the target
1384 will work. 32 (float) and 64 (double) are supported on all targets;
1385 80 or 128 (different flavors of long double) are also supported on some
1386 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1387
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1388 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1389 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1390 <i>size</i>.</dd>
1391
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1392 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1393 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1394 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1395
1396 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1397 <dd>This specifies a set of native integer widths for the target CPU
1398 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1399 "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]1400 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1401 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1402</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1403
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1404<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1405 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1406 specifications in the <tt>datalayout</tt> keyword. The default specifications
1407 are given in this list:</p>
1408
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1409<ul>
1410 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1411 <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]1412 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1413 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1414 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1415 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1416 <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]1417 alignment of 64-bits</li>
1418 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1419 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1420 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1421 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1422 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1423 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1424</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1425
1426<p>When LLVM is determining the alignment for a given type, it uses the
1427 following rules:</p>
1428
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1429<ol>
1430 <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]1431 specification is used.</li>
1432
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1433 <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]1434 smallest integer type that is larger than the bitwidth of the sought type
1435 is used. If none of the specifications are larger than the bitwidth then
Sylvestre Ledruc8e41c52012-07-23 08:51:15 +0000[diff] [blame]1436 the largest integer type is used. For example, given the default
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1437 specifications above, the i7 type will use the alignment of i8 (next
1438 largest) while both i65 and i256 will use the alignment of i64 (largest
1439 specified).</li>
1440
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1441 <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]1442 largest vector type that is smaller than the sought vector type will be
1443 used as a fall back. This happens because &lt;128 x double&gt; can be
1444 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1445</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1446
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1447<p>The function of the data layout string may not be what you expect. Notably,
1448 this is not a specification from the frontend of what alignment the code
1449 generator should use.</p>
1450
1451<p>Instead, if specified, the target data layout is required to match what the
1452 ultimate <em>code generator</em> expects. This string is used by the
1453 mid-level optimizers to
1454 improve code, and this only works if it matches what the ultimate code
1455 generator uses. If you would like to generate IR that does not embed this
1456 target-specific detail into the IR, then you don't have to specify the
1457 string. This will disable some optimizations that require precise layout
1458 information, but this also prevents those optimizations from introducing
1459 target specificity into the IR.</p>
1460
1461
1462
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1463</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1464
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1465<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1466<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1467 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1468</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1469
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1470<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1471
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1472<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1473with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1474is undefined. Pointer values are associated with address ranges
1475according to the following rules:</p>
1476
1477<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1478 <li>A pointer value is associated with the addresses associated with
1479 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1480 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1481 range of the variable's storage.</li>
1482 <li>The result value of an allocation instruction is associated with
1483 the address range of the allocated storage.</li>
1484 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1485 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1486 <li>An integer constant other than zero or a pointer value returned
1487 from a function not defined within LLVM may be associated with address
1488 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1489 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1490 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1491</ul>
1492
1493<p>A pointer value is <i>based</i> on another pointer value according
1494 to the following rules:</p>
1495
1496<ul>
1497 <li>A pointer value formed from a
1498 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1499 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1500 <li>The result value of a
1501 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1502 of the <tt>bitcast</tt>.</li>
1503 <li>A pointer value formed by an
1504 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1505 pointer values that contribute (directly or indirectly) to the
1506 computation of the pointer's value.</li>
1507 <li>The "<i>based</i> on" relationship is transitive.</li>
1508</ul>
1509
1510<p>Note that this definition of <i>"based"</i> is intentionally
1511 similar to the definition of <i>"based"</i> in C99, though it is
1512 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1513
1514<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1515<tt><a href="#i_load">load</a></tt> merely indicates the size and
1516alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1517interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1518<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1519and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1520
1521<p>Consequently, type-based alias analysis, aka TBAA, aka
1522<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1523LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1524additional information which specialized optimization passes may use
1525to implement type-based alias analysis.</p>
1526
1527</div>
1528
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1529<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1530<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1531 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1532</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1533
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1534<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1535
1536<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1537href="#i_store"><tt>store</tt></a>s, and <a
1538href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1539The optimizers must not change the number of volatile operations or change their
1540order of execution relative to other volatile operations. The optimizers
1541<i>may</i> change the order of volatile operations relative to non-volatile
1542operations. This is not Java's "volatile" and has no cross-thread
1543synchronization behavior.</p>
1544
1545</div>
1546
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1547<!-- ======================================================================= -->
1548<h3>
1549 <a name="memmodel">Memory Model for Concurrent Operations</a>
1550</h3>
1551
1552<div>
1553
1554<p>The LLVM IR does not define any way to start parallel threads of execution
1555or to register signal handlers. Nonetheless, there are platform-specific
1556ways to create them, and we define LLVM IR's behavior in their presence. This
1557model is inspired by the C++0x memory model.</p>
1558
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1559<p>For a more informal introduction to this model, see the
1560<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1561
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1562<p>We define a <i>happens-before</i> partial order as the least partial order
1563that</p>
1564<ul>
1565 <li>Is a superset of single-thread program order, and</li>
1566 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1567 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1568 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1569 creation, thread joining, etc., and by atomic instructions.
1570 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1571 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1572</ul>
1573
1574<p>Note that program order does not introduce <i>happens-before</i> edges
1575between a thread and signals executing inside that thread.</p>
1576
1577<p>Every (defined) read operation (load instructions, memcpy, atomic
1578loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1579(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1580stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1581initialized globals are considered to have a write of the initializer which is
1582atomic and happens before any other read or write of the memory in question.
1583For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1584any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1585
1586<ul>
1587 <li>If <var>write<sub>1</sub></var> happens before
1588 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1589 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1590 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1591 <li>If <var>R<sub>byte</sub></var> happens before
1592 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1593 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1594</ul>
1595
1596<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1597<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1598 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1599 is supposed to give guarantees which can support
1600 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1601 addresses which do not behave like normal memory. It does not generally
1602 provide cross-thread synchronization.)
1603 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1604 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1605 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1606 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1607 <var>R<sub>byte</sub></var> returns the value written by that
1608 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1609 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1610 <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]1611 values written. See the <a href="#ordering">Atomic Memory Ordering
1612 Constraints</a> section for additional constraints on how the choice
1613 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1614 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1615</ul>
1616
1617<p><var>R</var> returns the value composed of the series of bytes it read.
1618This implies that some bytes within the value may be <tt>undef</tt>
1619<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1620defines the semantics of the operation; it doesn't mean that targets will
1621emit more than one instruction to read the series of bytes.</p>
1622
1623<p>Note that in cases where none of the atomic intrinsics are used, this model
1624places only one restriction on IR transformations on top of what is required
1625for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1626otherwise be stored is not allowed in general. (Specifically, in the case
1627where another thread might write to and read from an address, introducing a
1628store can change a load that may see exactly one write into a load that may
1629see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1630
1631<!-- FIXME: This model assumes all targets where concurrency is relevant have
1632a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1633none of the backends currently in the tree fall into this category; however,
1634there might be targets which care. If there are, we want a paragraph
1635like the following:
1636
1637Targets may specify that stores narrower than a certain width are not
1638available; on such a target, for the purposes of this model, treat any
1639non-atomic write with an alignment or width less than the minimum width
1640as if it writes to the relevant surrounding bytes.
1641-->
1642
1643</div>
1644
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1645<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1646<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1647 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1648</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1649
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1650<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1651
1652<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1653<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1654<a href="#i_fence"><code>fence</code></a>,
1655<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1656<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1657that determines which other atomic instructions on the same address they
1658<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1659but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1660check those specs (see spec references in the
Nick Lewycky300a2632012-01-23 08:47:21 +0000[diff] [blame]1661<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1662<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1663treat these orderings somewhat differently since they don't take an address.
1664See that instruction's documentation for details.</p>
1665
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1666<p>For a simpler introduction to the ordering constraints, see the
1667<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1668
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1669<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1670<dt><code>unordered</code></dt>
1671<dd>The set of values that can be read is governed by the happens-before
1672partial order. A value cannot be read unless some operation wrote it.
1673This is intended to provide a guarantee strong enough to model Java's
1674non-volatile shared variables. This ordering cannot be specified for
1675read-modify-write operations; it is not strong enough to make them atomic
1676in any interesting way.</dd>
1677<dt><code>monotonic</code></dt>
1678<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1679total order for modifications by <code>monotonic</code> operations on each
1680address. All modification orders must be compatible with the happens-before
1681order. There is no guarantee that the modification orders can be combined to
1682a global total order for the whole program (and this often will not be
1683possible). The read in an atomic read-modify-write operation
1684(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1685<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1686reads the value in the modification order immediately before the value it
1687writes. If one atomic read happens before another atomic read of the same
1688address, the later read must see the same value or a later value in the
1689address's modification order. This disallows reordering of
1690<code>monotonic</code> (or stronger) operations on the same address. If an
1691address is written <code>monotonic</code>ally by one thread, and other threads
1692<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1693eventually see the write. This corresponds to the C++0x/C1x
1694<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1695<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1696<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1697a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1698operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1699<dt><code>release</code></dt>
1700<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1701writes a value which is subsequently read by an <code>acquire</code> operation,
1702it <i>synchronizes-with</i> that operation. (This isn't a complete
1703description; see the C++0x definition of a release sequence.) This corresponds
1704to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1705<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1706<code>acquire</code> and <code>release</code> operation on its address.
1707This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1708<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1709<dd>In addition to the guarantees of <code>acq_rel</code>
1710(<code>acquire</code> for an operation which only reads, <code>release</code>
1711for an operation which only writes), there is a global total order on all
1712sequentially-consistent operations on all addresses, which is consistent with
1713the <i>happens-before</i> partial order and with the modification orders of
1714all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1715preceding write to the same address in this global order. This corresponds
1716to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1717</dl>
1718
1719<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1720it only <i>synchronizes with</i> or participates in modification and seq_cst
1721total orderings with other operations running in the same thread (for example,
1722in signal handlers).</p>
1723
1724</div>
1725
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1726</div>
1727
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1728<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1729<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1730<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1731
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1732<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1734<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1735 intermediate representation. Being typed enables a number of optimizations
1736 to be performed on the intermediate representation directly, without having
1737 to do extra analyses on the side before the transformation. A strong type
1738 system makes it easier to read the generated code and enables novel analyses
1739 and transformations that are not feasible to perform on normal three address
1740 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1741
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1743<h3>
1744 <a name="t_classifications">Type Classifications</a>
1745</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1746
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1747<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1748
1749<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1750
1751<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1752 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1753 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1754 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1755 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1756 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1757 </tr>
1758 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1759 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1760 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1761 </tr>
1762 <tr>
1763 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1764 <td><a href="#t_integer">integer</a>,
1765 <a href="#t_floating">floating point</a>,
1766 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1767 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1768 <a href="#t_struct">structure</a>,
1769 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1770 <a href="#t_label">label</a>,
1771 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1772 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1773 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1774 <tr>
1775 <td><a href="#t_primitive">primitive</a></td>
1776 <td><a href="#t_label">label</a>,
1777 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1778 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1779 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1780 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1781 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1782 </tr>
1783 <tr>
1784 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1785 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1786 <a href="#t_function">function</a>,
1787 <a href="#t_pointer">pointer</a>,
1788 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1789 <a href="#t_vector">vector</a>,
1790 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1791 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1792 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1793 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1794</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1795
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1796<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1797 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1798 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1799
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1800</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1801
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1802<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1803<h3>
1804 <a name="t_primitive">Primitive Types</a>
1805</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1806
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1807<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1808
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1809<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1810 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1811
1812<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1813<h4>
1814 <a name="t_integer">Integer Type</a>
1815</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1816
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1817<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1818
1819<h5>Overview:</h5>
1820<p>The integer type is a very simple type that simply specifies an arbitrary
1821 bit width for the integer type desired. Any bit width from 1 bit to
1822 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1823
1824<h5>Syntax:</h5>
1825<pre>
1826 iN
1827</pre>
1828
1829<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1830 value.</p>
1831
1832<h5>Examples:</h5>
1833<table class="layout">
1834 <tr class="layout">
1835 <td class="left"><tt>i1</tt></td>
1836 <td class="left">a single-bit integer.</td>
1837 </tr>
1838 <tr class="layout">
1839 <td class="left"><tt>i32</tt></td>
1840 <td class="left">a 32-bit integer.</td>
1841 </tr>
1842 <tr class="layout">
1843 <td class="left"><tt>i1942652</tt></td>
1844 <td class="left">a really big integer of over 1 million bits.</td>
1845 </tr>
1846</table>
1847
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1848</div>
1849
1850<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1851<h4>
1852 <a name="t_floating">Floating Point Types</a>
1853</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1854
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1855<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1856
1857<table>
1858 <tbody>
1859 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1860 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1861 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1862 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1863 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1864 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1865 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1866 </tbody>
1867</table>
1868
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1869</div>
1870
1871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1872<h4>
1873 <a name="t_x86mmx">X86mmx Type</a>
1874</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1876<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1877
1878<h5>Overview:</h5>
1879<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>
1880
1881<h5>Syntax:</h5>
1882<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1883 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1884</pre>
1885
1886</div>
1887
1888<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1889<h4>
1890 <a name="t_void">Void Type</a>
1891</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1892
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1893<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1894
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1895<h5>Overview:</h5>
1896<p>The void type does not represent any value and has no size.</p>
1897
1898<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1899<pre>
1900 void
1901</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1902
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1903</div>
1904
1905<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1906<h4>
1907 <a name="t_label">Label Type</a>
1908</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1909
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1910<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1911
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1912<h5>Overview:</h5>
1913<p>The label type represents code labels.</p>
1914
1915<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1916<pre>
1917 label
1918</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1919
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1920</div>
1921
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1923<h4>
1924 <a name="t_metadata">Metadata Type</a>
1925</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1927<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1928
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1929<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1930<p>The metadata type represents embedded metadata. No derived types may be
1931 created from metadata except for <a href="#t_function">function</a>
1932 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1933
1934<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1935<pre>
1936 metadata
1937</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1938
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1939</div>
1940
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1941</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1942
1943<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1944<h3>
1945 <a name="t_derived">Derived Types</a>
1946</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1947
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1948<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1949
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1950<p>The real power in LLVM comes from the derived types in the system. This is
1951 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1952 useful types. Each of these types contain one or more element types which
1953 may be a primitive type, or another derived type. For example, it is
1954 possible to have a two dimensional array, using an array as the element type
1955 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1956
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1957<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1958<h4>
1959 <a name="t_aggregate">Aggregate Types</a>
1960</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1961
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1962<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1963
1964<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1965 member types. <a href="#t_array">Arrays</a> and
1966 <a href="#t_struct">structs</a> are aggregate types.
1967 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1968
1969</div>
1970
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1971<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1972<h4>
1973 <a name="t_array">Array Type</a>
1974</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1976<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1979<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1980 sequentially in memory. The array type requires a size (number of elements)
1981 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1982
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1983<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1984<pre>
1985 [&lt;# elements&gt; x &lt;elementtype&gt;]
1986</pre>
1987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1989 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1990
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1991<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1992<table class="layout">
1993 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1994 <td class="left"><tt>[40 x i32]</tt></td>
1995 <td class="left">Array of 40 32-bit integer values.</td>
1996 </tr>
1997 <tr class="layout">
1998 <td class="left"><tt>[41 x i32]</tt></td>
1999 <td class="left">Array of 41 32-bit integer values.</td>
2000 </tr>
2001 <tr class="layout">
2002 <td class="left"><tt>[4 x i8]</tt></td>
2003 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2004 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2005</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2006<p>Here are some examples of multidimensional arrays:</p>
2007<table class="layout">
2008 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2009 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
2010 <td class="left">3x4 array of 32-bit integer values.</td>
2011 </tr>
2012 <tr class="layout">
2013 <td class="left"><tt>[12 x [10 x float]]</tt></td>
2014 <td class="left">12x10 array of single precision floating point values.</td>
2015 </tr>
2016 <tr class="layout">
2017 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
2018 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2019 </tr>
2020</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2021
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]2022<p>There is no restriction on indexing beyond the end of the array implied by
2023 a static type (though there are restrictions on indexing beyond the bounds
2024 of an allocated object in some cases). This means that single-dimension
2025 'variable sized array' addressing can be implemented in LLVM with a zero
2026 length array type. An implementation of 'pascal style arrays' in LLVM could
2027 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2028
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2029</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2030
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2031<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2032<h4>
2033 <a name="t_function">Function Type</a>
2034</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2036<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2037
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2038<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2039<p>The function type can be thought of as a function signature. It consists of
2040 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]2041 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]2042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2044<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2045 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2046</pre>
2047
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2048<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]2049 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2050 which indicates that the function takes a variable number of arguments.
2051 Variable argument functions can access their arguments with
2052 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2053 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2054 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2055
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2056<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2057<table class="layout">
2058 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2059 <td class="left"><tt>i32 (i32)</tt></td>
2060 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2061 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2062 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2063 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2064 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2065 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2066 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2067 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2068 </td>
2069 </tr><tr class="layout">
2070 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2071 <td class="left">A vararg function that takes at least one
2072 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2073 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2074 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2075 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2076 </tr><tr class="layout">
2077 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2078 <td class="left">A function taking an <tt>i32</tt>, returning a
2079 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2080 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2081 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2082</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2083
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2084</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2085
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2087<h4>
2088 <a name="t_struct">Structure Type</a>
2089</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2090
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2091<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2092
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2093<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2094<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2095 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]2096
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2097<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2098 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2099 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2100 Structures in registers are accessed using the
2101 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2102 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2103
2104<p>Structures may optionally be "packed" structures, which indicate that the
2105 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2106 the elements. In non-packed structs, padding between field types is inserted
2107 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2108 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2109
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2110<p>Structures can either be "literal" or "identified". A literal structure is
2111 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2112 types are always defined at the top level with a name. Literal types are
2113 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2114 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]2115 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2116</p>
2117
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2118<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2119<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2120 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2121 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2122</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2123
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2124<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2125<table class="layout">
2126 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2127 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2128 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2129 </tr>
2130 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2131 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2132 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2133 second element is a <a href="#t_pointer">pointer</a> to a
2134 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2135 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2136 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2137 <tr class="layout">
2138 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2139 <td class="left">A packed struct known to be 5 bytes in size.</td>
2140 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2141</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2142
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2143</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2144
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2145<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2146<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2147 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2148</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2149
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2150<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2151
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2152<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2153<p>Opaque structure types are used to represent named structure types that do
2154 not have a body specified. This corresponds (for example) to the C notion of
2155 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2156
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2157<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2158<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2159 %X = type opaque
2160 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2161</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2162
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2163<h5>Examples:</h5>
2164<table class="layout">
2165 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2166 <td class="left"><tt>opaque</tt></td>
2167 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2168 </tr>
2169</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2170
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2171</div>
2172
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2173
2174
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2175<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2176<h4>
2177 <a name="t_pointer">Pointer Type</a>
2178</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2179
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2180<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181
2182<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2183<p>The pointer type is used to specify memory locations.
2184 Pointers are commonly used to reference objects in memory.</p>
2185
2186<p>Pointer types may have an optional address space attribute defining the
2187 numbered address space where the pointed-to object resides. The default
2188 address space is number zero. The semantics of non-zero address
2189 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2190
2191<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2192 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2193
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2194<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2195<pre>
2196 &lt;type&gt; *
2197</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2198
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2199<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2200<table class="layout">
2201 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2202 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2203 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2204 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2205 </tr>
2206 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2207 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2208 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2209 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2210 <tt>i32</tt>.</td>
2211 </tr>
2212 <tr class="layout">
2213 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2214 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2215 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2216 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2217</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2219</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2220
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2221<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2222<h4>
2223 <a name="t_vector">Vector Type</a>
2224</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2225
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2226<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2227
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2228<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2229<p>A vector type is a simple derived type that represents a vector of elements.
2230 Vector types are used when multiple primitive data are operated in parallel
2231 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2232 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2233 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2234
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2235<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2236<pre>
2237 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2238</pre>
2239
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2240<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2241 may be any integer or floating point type, or a pointer to these types.
2242 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2243
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2244<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2245<table class="layout">
2246 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2247 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2248 <td class="left">Vector of 4 32-bit integer values.</td>
2249 </tr>
2250 <tr class="layout">
2251 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2252 <td class="left">Vector of 8 32-bit floating-point values.</td>
2253 </tr>
2254 <tr class="layout">
2255 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2256 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2257 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2258 <tr class="layout">
2259 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2260 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2261 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2262</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2263
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2264</div>
2265
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2266</div>
2267
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2268</div>
2269
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2270<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2271<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2272<!-- *********************************************************************** -->
2273
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2274<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2275
2276<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2277 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2278
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2279<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2280<h3>
2281 <a name="simpleconstants">Simple Constants</a>
2282</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2283
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2284<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2285
2286<dl>
2287 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2288 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2289 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2290
2291 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2292 <dd>Standard integers (such as '4') are constants of
2293 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2294 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2295
2296 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2297 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2298 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2299 notation (see below). The assembler requires the exact decimal value of a
2300 floating-point constant. For example, the assembler accepts 1.25 but
2301 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2302 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2303
2304 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2305 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2306 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2307</dl>
2308
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2309<p>The one non-intuitive notation for constants is the hexadecimal form of
2310 floating point constants. For example, the form '<tt>double
2311 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2312 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2313 constants are required (and the only time that they are generated by the
2314 disassembler) is when a floating point constant must be emitted but it cannot
2315 be represented as a decimal floating point number in a reasonable number of
2316 digits. For example, NaN's, infinities, and other special values are
2317 represented in their IEEE hexadecimal format so that assembly and disassembly
2318 do not cause any bits to change in the constants.</p>
2319
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2320<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2321 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2322 representation for double); half and float values must, however, be exactly
2323 representable as IEE754 half and single precision, respectively.
2324 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2325 for long double, and there are three forms of long double. The 80-bit format
2326 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2327 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2328 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2329 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2330 currently supported target uses this format. Long doubles will only work if
Tobias Grosser057beb82012-05-24 15:59:06 +0000[diff] [blame]2331 they match the long double format on your target. The IEEE 16-bit format
2332 (half precision) is represented by <tt>0xH</tt> followed by 4 hexadecimal
2333 digits. All hexadecimal formats are big-endian (sign bit at the left).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2334
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2335<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2336</div>
2337
2338<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2339<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2340<a name="aggregateconstants"></a> <!-- old anchor -->
2341<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2342</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2343
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2344<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2345
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2346<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2347 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2348
2349<dl>
2350 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2351 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2352 type definitions (a comma separated list of elements, surrounded by braces
2353 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2354 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2355 Structure constants must have <a href="#t_struct">structure type</a>, and
2356 the number and types of elements must match those specified by the
2357 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2358
2359 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2360 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2361 definitions (a comma separated list of elements, surrounded by square
2362 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2363 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2364 the number and types of elements must match those specified by the
2365 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2366
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2367 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2368 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2369 definitions (a comma separated list of elements, surrounded by
2370 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2371 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2372 have <a href="#t_vector">vector type</a>, and the number and types of
2373 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2374
2375 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2376 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2377 value to zero of <em>any</em> type, including scalar and
2378 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2379 This is often used to avoid having to print large zero initializers
2380 (e.g. for large arrays) and is always exactly equivalent to using explicit
2381 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2382
2383 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2384 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2385 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2386 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2387 be interpreted as part of the instruction stream, metadata is a place to
2388 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2389</dl>
2390
2391</div>
2392
2393<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2394<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2395 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2396</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2397
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2398<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2399
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2400<p>The addresses of <a href="#globalvars">global variables</a>
2401 and <a href="#functionstructure">functions</a> are always implicitly valid
2402 (link-time) constants. These constants are explicitly referenced when
2403 the <a href="#identifiers">identifier for the global</a> is used and always
2404 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2405 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2406
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2407<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2408@X = global i32 17
2409@Y = global i32 42
2410@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2411</pre>
2412
2413</div>
2414
2415<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2416<h3>
2417 <a name="undefvalues">Undefined Values</a>
2418</h3>
2419
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2420<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2421
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2422<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]2423 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2424 Undefined values may be of any type (other than '<tt>label</tt>'
2425 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2426
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2427<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2428 program is well defined no matter what value is used. This gives the
2429 compiler more freedom to optimize. Here are some examples of (potentially
2430 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2431
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2432
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2433<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2434 %A = add %X, undef
2435 %B = sub %X, undef
2436 %C = xor %X, undef
2437Safe:
2438 %A = undef
2439 %B = undef
2440 %C = undef
2441</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2442
2443<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]2444 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]2445
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2446<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2447 %A = or %X, undef
2448 %B = and %X, undef
2449Safe:
2450 %A = -1
2451 %B = 0
2452Unsafe:
2453 %A = undef
2454 %B = undef
2455</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2456
2457<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2458 For example, if <tt>%X</tt> has a zero bit, then the output of the
2459 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2460 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2461 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2462 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2463 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2464 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2465 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2466
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2467<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2468 %A = select undef, %X, %Y
2469 %B = select undef, 42, %Y
2470 %C = select %X, %Y, undef
2471Safe:
2472 %A = %X (or %Y)
2473 %B = 42 (or %Y)
2474 %C = %Y
2475Unsafe:
2476 %A = undef
2477 %B = undef
2478 %C = undef
2479</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2480
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2481<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2482 branch) conditions can go <em>either way</em>, but they have to come from one
2483 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2484 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2485 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2486 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2487 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2488 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2489
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2490<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2491 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2492
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2493 %B = undef
2494 %C = xor %B, %B
2495
2496 %D = undef
2497 %E = icmp lt %D, 4
2498 %F = icmp gte %D, 4
2499
2500Safe:
2501 %A = undef
2502 %B = undef
2503 %C = undef
2504 %D = undef
2505 %E = undef
2506 %F = undef
2507</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2508
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2509<p>This example points out that two '<tt>undef</tt>' operands are not
2510 necessarily the same. This can be surprising to people (and also matches C
2511 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2512 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2513 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2514 its value over its "live range". This is true because the variable doesn't
2515 actually <em>have a live range</em>. Instead, the value is logically read
2516 from arbitrary registers that happen to be around when needed, so the value
2517 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2518 need to have the same semantics or the core LLVM "replace all uses with"
2519 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2520
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2521<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2522 %A = fdiv undef, %X
2523 %B = fdiv %X, undef
2524Safe:
2525 %A = undef
2526b: unreachable
2527</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2528
2529<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2530 value</em> and <em>undefined behavior</em>. An undefined value (like
2531 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2532 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2533 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2534 defined on SNaN's. However, in the second example, we can make a more
2535 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2536 arbitrary value, we are allowed to assume that it could be zero. Since a
2537 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2538 the operation does not execute at all. This allows us to delete the divide and
2539 all code after it. Because the undefined operation "can't happen", the
2540 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2541
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2542<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2543a: store undef -> %X
2544b: store %X -> undef
2545Safe:
2546a: &lt;deleted&gt;
2547b: unreachable
2548</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2549
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2550<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2551 undefined value can be assumed to not have any effect; we can assume that the
2552 value is overwritten with bits that happen to match what was already there.
2553 However, a store <em>to</em> an undefined location could clobber arbitrary
2554 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2555
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2556</div>
2557
2558<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2559<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2560 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2561</h3>
2562
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2563<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2564
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2565<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2566 they also represent the fact that an instruction or constant expression which
2567 cannot evoke side effects has nevertheless detected a condition which results
2568 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2569
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2570<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]2571 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2572 <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]2573
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2574<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2575
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2576<ul>
2577<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2578 their operands.</li>
2579
2580<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2581 to their dynamic predecessor basic block.</li>
2582
2583<li>Function arguments depend on the corresponding actual argument values in
2584 the dynamic callers of their functions.</li>
2585
2586<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2587 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2588 control back to them.</li>
2589
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2590<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]2591 <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]2592 or exception-throwing call instructions that dynamically transfer control
2593 back to them.</li>
2594
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2595<li>Non-volatile loads and stores depend on the most recent stores to all of the
2596 referenced memory addresses, following the order in the IR
2597 (including loads and stores implied by intrinsics such as
2598 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2599
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2600<!-- TODO: In the case of multiple threads, this only applies if the store
2601 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2602
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2603<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2604
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2605<li>An instruction with externally visible side effects depends on the most
2606 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2607 the order in the IR. (This includes
2608 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2609
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2610<li>An instruction <i>control-depends</i> on a
2611 <a href="#terminators">terminator instruction</a>
2612 if the terminator instruction has multiple successors and the instruction
2613 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2614 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2615
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2616<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2617 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2618 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2619 successor.</li>
2620
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2621<li>Dependence is transitive.</li>
2622
2623</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2624
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2625<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2626 with the additional affect that any instruction which has a <i>dependence</i>
2627 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2628
2629<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2630
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2631<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2632entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2633 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2634 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2635 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2636 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2637
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2638 store i32 %poison, i32* @g ; Poison value stored to memory.
2639 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2640
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2641 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2642
2643 %narrowaddr = bitcast i32* @g to i16*
2644 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2645 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2646 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2647
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2648 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2649 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2650
2651true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2652 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2653 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2654 br label %end
2655
2656end:
2657 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2658 ; Both edges into this PHI are
2659 ; control-dependent on %cmp, so this
2660 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2661
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2662 store volatile i32 0, i32* @g ; This would depend on the store in %true
2663 ; if %cmp is true, or the store in %entry
2664 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2665
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2666 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2667 ; The same branch again, but this time the
2668 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2669
2670second_true:
2671 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2672 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2673
2674second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2675 store volatile i32 0, i32* @g ; This time, the instruction always depends
2676 ; on the store in %end. Also, it is
2677 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2678 ; well-defined (ignoring earlier undefined
2679 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2680</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2681
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2682</div>
2683
2684<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2685<h3>
2686 <a name="blockaddress">Addresses of Basic Blocks</a>
2687</h3>
2688
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2689<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2690
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2691<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2692
2693<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2694 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2695 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2696
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2697<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2698 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2699 comparisons against null. Pointer equality tests between labels addresses
2700 results in undefined behavior &mdash; though, again, comparison against null
2701 is ok, and no label is equal to the null pointer. This may be passed around
2702 as an opaque pointer sized value as long as the bits are not inspected. This
2703 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2704 long as the original value is reconstituted before the <tt>indirectbr</tt>
2705 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2706
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2707<p>Finally, some targets may provide defined semantics when using the value as
2708 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2709
2710</div>
2711
2712
2713<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2714<h3>
2715 <a name="constantexprs">Constant Expressions</a>
2716</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2718<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2719
2720<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2721 to be used as constants. Constant expressions may be of
2722 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2723 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2724 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2725
2726<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2727 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2728 <dd>Truncate a constant to another type. The bit size of CST must be larger
2729 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2730
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2731 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2732 <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]2733 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2734
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2736 <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]2737 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2738
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2740 <dd>Truncate a floating point constant to another floating point type. The
2741 size of CST must be larger than the size of TYPE. Both types must be
2742 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2743
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2744 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2745 <dd>Floating point extend a constant to another type. The size of CST must be
2746 smaller or equal to the size of TYPE. Both types must be floating
2747 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2748
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2749 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2750 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2751 constant. TYPE must be a scalar or vector integer type. CST must be of
2752 scalar or vector floating point type. Both CST and TYPE must be scalars,
2753 or vectors of the same number of elements. If the value won't fit in the
2754 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2755
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2756 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2757 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2758 constant. TYPE must be a scalar or vector integer type. CST must be of
2759 scalar or vector floating point type. Both CST and TYPE must be scalars,
2760 or vectors of the same number of elements. If the value won't fit in the
2761 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2762
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2764 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2765 constant. TYPE must be a scalar or vector floating point type. CST must be
2766 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2767 vectors of the same number of elements. If the value won't fit in the
2768 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2769
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2770 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2771 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2772 constant. TYPE must be a scalar or vector floating point type. CST must be
2773 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2774 vectors of the same number of elements. If the value won't fit in the
2775 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2776
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2777 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2778 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2779 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2780 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2781 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2782
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2783 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Sylvestre Ledru7f7390e2012-07-25 22:01:31 +0000[diff] [blame]2784 <dd>Convert an integer constant to a pointer constant. TYPE must be a pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2785 type. CST must be of integer type. The CST value is zero extended,
2786 truncated, or unchanged to make it fit in a pointer size. This one is
2787 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2788
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2789 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2790 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2791 are the same as those for the <a href="#i_bitcast">bitcast
2792 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2793
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2794 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2795 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2796 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2797 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2798 instruction, the index list may have zero or more indexes, which are
2799 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2801 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2802 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2803
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2804 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2805 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2806
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2807 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2808 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2809
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2810 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2811 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2812 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2813
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2814 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2816 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2817
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2818 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2819 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2820 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2821
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2822 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2823 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2824 constants. The index list is interpreted in a similar manner as indices in
2825 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2826 index value must be specified.</dd>
2827
2828 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2829 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2830 constants. The index list is interpreted in a similar manner as indices in
2831 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2832 index value must be specified.</dd>
2833
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2834 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2835 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2836 be any of the <a href="#binaryops">binary</a>
2837 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2838 on operands are the same as those for the corresponding instruction
2839 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2840</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2841
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2842</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2843
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2844</div>
2845
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2846<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2847<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2848<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2849<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2850<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2851<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2852<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2853</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2854
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2855<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2857<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2858 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2859 a special value. This value represents the inline assembler as a string
2860 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2861 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2862 expression has side effects, and a flag indicating whether the function
2863 containing the asm needs to align its stack conservatively. An example
2864 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2865
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2866<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2867i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2868</pre>
2869
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2870<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
Nuno Lopes0b5f1ac2012-07-17 23:51:33 +0000[diff] [blame]2871 a <a href="#i_call"><tt>call</tt></a> or an
2872 <a href="#i_invoke"><tt>invoke</tt></a> instruction.
2873 Thus, typically we have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2874
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2875<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2876%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]2877</pre>
2878
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2879<p>Inline asms with side effects not visible in the constraint list must be
2880 marked as having side effects. This is done through the use of the
2881 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2882
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2883<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2884call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2885</pre>
2886
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2887<p>In some cases inline asms will contain code that will not work unless the
2888 stack is aligned in some way, such as calls or SSE instructions on x86,
2889 yet will not contain code that does that alignment within the asm.
2890 The compiler should make conservative assumptions about what the asm might
2891 contain and should generate its usual stack alignment code in the prologue
2892 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2893
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2894<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2895call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2896</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2897
Chad Rosier581600b2012-09-05 19:00:49 +0000[diff] [blame]2898<p>Inline asms also support using non-standard assembly dialects. The assumed
2899 dialect is ATT. When the '<tt>inteldialect</tt>' keyword is present, the
2900 inline asm is using the Intel dialect. Currently, ATT and Intel are the
2901 only supported dialects. An example is:</p>
Chad Rosier36547342012-09-05 00:08:17 +0000[diff] [blame]2902
2903<pre class="doc_code">
Chad Rosier581600b2012-09-05 19:00:49 +0000[diff] [blame]2904call void asm inteldialect "eieio", ""()
Chad Rosier36547342012-09-05 00:08:17 +0000[diff] [blame]2905</pre>
2906
2907<p>If multiple keywords appear the '<tt>sideeffect</tt>' keyword must come
2908 first, the '<tt>alignstack</tt>' keyword second and the
Chad Rosier581600b2012-09-05 19:00:49 +0000[diff] [blame]2909 '<tt>inteldialect</tt>' keyword last.</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2910
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2911<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2912<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2913 documented here. Constraints on what can be done (e.g. duplication, moving,
2914 etc need to be documented). This is probably best done by reference to
2915 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2916 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2917
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2918<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2919<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2920 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2921</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2922
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2923<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2924
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2925<p>The call instructions that wrap inline asm nodes may have a
2926 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2927 integers. If present, the code generator will use the integer as the
2928 location cookie value when report errors through the <tt>LLVMContext</tt>
2929 error reporting mechanisms. This allows a front-end to correlate backend
2930 errors that occur with inline asm back to the source code that produced it.
2931 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2932
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2933<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2934call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2935...
2936!42 = !{ i32 1234567 }
2937</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2938
2939<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]2940 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2941 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]2942
2943</div>
2944
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2945</div>
2946
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2947<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2948<h3>
2949 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2950</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2951
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2952<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2953
2954<p>LLVM IR allows metadata to be attached to instructions in the program that
2955 can convey extra information about the code to the optimizers and code
2956 generator. One example application of metadata is source-level debug
2957 information. There are two metadata primitives: strings and nodes. All
2958 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2959 preceding exclamation point ('<tt>!</tt>').</p>
2960
2961<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2962 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2963 "<tt>xx</tt>" is the two digit hex code. For example:
2964 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2965
2966<p>Metadata nodes are represented with notation similar to structure constants
2967 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2968 exclamation point). Metadata nodes can have any values as their operand. For
2969 example:</p>
2970
2971<div class="doc_code">
2972<pre>
2973!{ metadata !"test\00", i32 10}
2974</pre>
2975</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2976
2977<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2978 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2979 example:</p>
2980
2981<div class="doc_code">
2982<pre>
2983!foo = metadata !{!4, !3}
2984</pre>
2985</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2986
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2987<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2988 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2989
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2990<div class="doc_code">
2991<pre>
2992call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2993</pre>
2994</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2995
2996<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2997 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2998 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2999
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]3000<div class="doc_code">
3001<pre>
3002%indvar.next = add i64 %indvar, 1, !dbg !21
3003</pre>
3004</div>
3005
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]3006<p>More information about specific metadata nodes recognized by the optimizers
3007 and code generator is found below.</p>
3008
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]3009<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]3010<h4>
3011 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
3012</h4>
3013
3014<div>
3015
3016<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
3017 suitable for doing TBAA. Instead, metadata is added to the IR to describe
3018 a type system of a higher level language. This can be used to implement
3019 typical C/C++ TBAA, but it can also be used to implement custom alias
3020 analysis behavior for other languages.</p>
3021
3022<p>The current metadata format is very simple. TBAA metadata nodes have up to
3023 three fields, e.g.:</p>
3024
3025<div class="doc_code">
3026<pre>
3027!0 = metadata !{ metadata !"an example type tree" }
3028!1 = metadata !{ metadata !"int", metadata !0 }
3029!2 = metadata !{ metadata !"float", metadata !0 }
3030!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
3031</pre>
3032</div>
3033
3034<p>The first field is an identity field. It can be any value, usually
3035 a metadata string, which uniquely identifies the type. The most important
3036 name in the tree is the name of the root node. Two trees with
3037 different root node names are entirely disjoint, even if they
3038 have leaves with common names.</p>
3039
3040<p>The second field identifies the type's parent node in the tree, or
3041 is null or omitted for a root node. A type is considered to alias
3042 all of its descendants and all of its ancestors in the tree. Also,
3043 a type is considered to alias all types in other trees, so that
3044 bitcode produced from multiple front-ends is handled conservatively.</p>
3045
3046<p>If the third field is present, it's an integer which if equal to 1
3047 indicates that the type is "constant" (meaning
3048 <tt>pointsToConstantMemory</tt> should return true; see
3049 <a href="AliasAnalysis.html#OtherItfs">other useful
3050 <tt>AliasAnalysis</tt> methods</a>).</p>
3051
3052</div>
3053
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]3054<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3055<h4>
Dan Gohman273a92e2012-09-21 18:21:48 +0000[diff] [blame]3056 <a name="tbaa.struct">'<tt>tbaa.struct</tt>' Metadata</a>
3057</h4>
3058
3059<div>
3060
3061<p>The <a href="#int_memcpy"><tt>llvm.memcpy</tt></a> is often used to implement
3062aggregate assignment operations in C and similar languages, however it is
3063defined to copy a contiguous region of memory, which is more than strictly
3064necessary for aggregate types which contain holes due to padding. Also, it
3065doesn't contain any TBAA information about the fields of the aggregate.</p>
3066
3067<p><tt>!tbaa.struct</tt> metadata can describe which memory subregions in a memcpy
3068are padding and what the TBAA tags of the struct are.</p>
3069
3070<p>The current metadata format is very simple. <tt>!tbaa.struct</tt> metadata nodes
3071 are a list of operands which are in conceptual groups of three. For each
Dan Gohmanee9f7262012-09-21 18:41:30 +0000[diff] [blame]3072 group of three, the first operand gives the byte offset of a field in bytes,
3073 the second gives its size in bytes, and the third gives its
Dan Gohman273a92e2012-09-21 18:21:48 +0000[diff] [blame]3074 tbaa tag. e.g.:</p>
3075
3076<div class="doc_code">
3077<pre>
3078!4 = metadata !{ i64 0, i64 4, metadata !1, i64 8, i64 4, metadata !2 }
3079</pre>
3080</div>
3081
Dan Gohmanee9f7262012-09-21 18:41:30 +0000[diff] [blame]3082<p>This describes a struct with two fields. The first is at offset 0 bytes
3083 with size 4 bytes, and has tbaa tag !1. The second is at offset 8 bytes
3084 and has size 4 bytes and has tbaa tag !2.</p>
Dan Gohman273a92e2012-09-21 18:21:48 +0000[diff] [blame]3085
3086<p>Note that the fields need not be contiguous. In this example, there is a
3087 4 byte gap between the two fields. This gap represents padding which
3088 does not carry useful data and need not be preserved.</p>
3089
3090</div>
3091
3092<!-- _______________________________________________________________________ -->
3093<h4>
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3094 <a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3095</h4>
3096
3097<div>
3098
Duncan Sands5e5c5f82012-04-14 12:36:06 +0000[diff] [blame]3099<p><tt>fpmath</tt> metadata may be attached to any instruction of floating point
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3100 type. It can be used to express the maximum acceptable error in the result of
3101 that instruction, in ULPs, thus potentially allowing the compiler to use a
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3102 more efficient but less accurate method of computing it. ULP is defined as
3103 follows:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3104
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3105<blockquote>
3106
3107<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3108 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3109 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3110 distance between the two non-equal finite floating-point numbers nearest
3111 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3112
3113</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3114
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3115<p>The metadata node shall consist of a single positive floating point number
Duncan Sands2867c852012-04-16 19:39:33 +0000[diff] [blame]3116 representing the maximum relative error, for example:</p>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3117
3118<div class="doc_code">
3119<pre>
Duncan Sands8883c432012-04-16 16:28:59 +0000[diff] [blame]3120!0 = metadata !{ float 2.5 } ; maximum acceptable inaccuracy is 2.5 ULPs
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3121</pre>
3122</div>
3123
NAKAMURA Takumi9c55f592012-03-27 11:25:16 +0000[diff] [blame]3124</div>
3125
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3126<!-- _______________________________________________________________________ -->
3127<h4>
3128 <a name="range">'<tt>range</tt>' Metadata</a>
3129</h4>
3130
3131<div>
3132<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3133 expresses the possible ranges the loaded value is in. The ranges are
3134 represented with a flattened list of integers. The loaded value is known to
3135 be in the union of the ranges defined by each consecutive pair. Each pair
3136 has the following properties:</p>
3137<ul>
3138 <li>The type must match the type loaded by the instruction.</li>
3139 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3140 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3141 <li>The range is allowed to wrap.</li>
3142 <li>The range should not represent the full or empty set. That is,
3143 <tt>a!=b</tt>. </li>
3144</ul>
Rafael Espindolaa1b95f52012-05-31 16:04:26 +0000[diff] [blame]3145<p> In addition, the pairs must be in signed order of the lower bound and
3146 they must be non-contiguous.</p>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3147
3148<p>Examples:</p>
3149<div class="doc_code">
3150<pre>
3151 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3152 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3153 %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]3154 %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]3155...
3156!0 = metadata !{ i8 0, i8 2 }
3157!1 = metadata !{ i8 255, i8 2 }
3158!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
Rafael Espindolac49b29e2012-05-31 13:45:46 +0000[diff] [blame]3159!3 = metadata !{ i8 -2, i8 0, i8 3, i8 6 }
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3160</pre>
3161</div>
3162</div>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3163</div>
3164
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3165</div>
3166
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3167<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3168<h2>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3169 <a name="module_flags">Module Flags Metadata</a>
3170</h2>
3171<!-- *********************************************************************** -->
3172
3173<div>
3174
3175<p>Information about the module as a whole is difficult to convey to LLVM's
3176 subsystems. The LLVM IR isn't sufficient to transmit this
3177 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3178 facilitate this. These flags are in the form of key / value pairs &mdash;
3179 much like a dictionary &mdash; making it easy for any subsystem who cares
3180 about a flag to look it up.</p>
3181
3182<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3183 triplets. Each triplet has the following form:</p>
3184
3185<ul>
3186 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3187 when two (or more) modules are merged together, and it encounters two (or
3188 more) metadata with the same ID. The supported behaviors are described
3189 below.</li>
3190
3191 <li>The second element is a metadata string that is a unique ID for the
3192 metadata. How each ID is interpreted is documented below.</li>
3193
3194 <li>The third element is the value of the flag.</li>
3195</ul>
3196
3197<p>When two (or more) modules are merged together, the resulting
3198 <tt>llvm.module.flags</tt> metadata is the union of the
3199 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3200 with the <i>Override</i> behavior, which may override another flag's value
3201 (see below).</p>
3202
3203<p>The following behaviors are supported:</p>
3204
3205<table border="1" cellspacing="0" cellpadding="4">
3206 <tbody>
3207 <tr>
3208 <th>Value</th>
3209 <th>Behavior</th>
3210 </tr>
3211 <tr>
3212 <td>1</td>
3213 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3214 <dl>
3215 <dt><b>Error</b></dt>
3216 <dd>Emits an error if two values disagree. It is an error to have an ID
3217 with both an Error and a Warning behavior.</dd>
3218 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3219 </td>
3220 </tr>
3221 <tr>
3222 <td>2</td>
3223 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3224 <dl>
3225 <dt><b>Warning</b></dt>
3226 <dd>Emits a warning if two values disagree.</dd>
3227 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3228 </td>
3229 </tr>
3230 <tr>
3231 <td>3</td>
3232 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3233 <dl>
3234 <dt><b>Require</b></dt>
3235 <dd>Emits an error when the specified value is not present or doesn't
3236 have the specified value. It is an error for two (or more)
3237 <tt>llvm.module.flags</tt> with the same ID to have the Require
3238 behavior but different values. There may be multiple Require flags
3239 per ID.</dd>
3240 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3241 </td>
3242 </tr>
3243 <tr>
3244 <td>4</td>
3245 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3246 <dl>
3247 <dt><b>Override</b></dt>
3248 <dd>Uses the specified value if the two values disagree. It is an
3249 error for two (or more) <tt>llvm.module.flags</tt> with the same
3250 ID to have the Override behavior but different values.</dd>
3251 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3252 </td>
3253 </tr>
3254 </tbody>
3255</table>
3256
3257<p>An example of module flags:</p>
3258
3259<pre class="doc_code">
3260!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3261!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3262!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3263!3 = metadata !{ i32 3, metadata !"qux",
3264 metadata !{
3265 metadata !"foo", i32 1
3266 }
3267}
3268!llvm.module.flags = !{ !0, !1, !2, !3 }
3269</pre>
3270
3271<ul>
3272 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3273 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3274 error if their values are not equal.</p></li>
3275
3276 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3277 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3278 value '37' if their values are not equal.</p></li>
3279
3280 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3281 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3282 warning if their values are not equal.</p></li>
3283
3284 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3285
3286<pre class="doc_code">
3287metadata !{ metadata !"foo", i32 1 }
3288</pre>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3289
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3290 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3291 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3292 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3293 the same value or an error will be issued.</p></li>
3294</ul>
3295
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3296
3297<!-- ======================================================================= -->
3298<h3>
3299<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3300</h3>
3301
3302<div>
3303
3304<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3305 in a special section called "image info". The metadata consists of a version
3306 number and a bitmask specifying what types of garbage collection are
3307 supported (if any) by the file. If two or more modules are linked together
3308 their garbage collection metadata needs to be merged rather than appended
3309 together.</p>
3310
3311<p>The Objective-C garbage collection module flags metadata consists of the
3312 following key-value pairs:</p>
3313
3314<table border="1" cellspacing="0" cellpadding="4">
Bill Wendlingb3ef2232012-03-06 09:23:25 +0000[diff] [blame]3315 <col width="30%">
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3316 <tbody>
3317 <tr>
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3318 <th>Key</th>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3319 <th>Value</th>
3320 </tr>
3321 <tr>
3322 <td><tt>Objective-C&nbsp;Version</tt></td>
3323 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3324 version. Valid values are 1 and 2.</td>
3325 </tr>
3326 <tr>
3327 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3328 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3329 section. Currently always 0.</td>
3330 </tr>
3331 <tr>
3332 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3333 <td align="left"><b>[Required]</b> &mdash; The section to place the
3334 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3335 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3336 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3337 </tr>
3338 <tr>
3339 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3340 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3341 collection is supported or not. Valid values are 0, for no garbage
3342 collection, and 2, for garbage collection supported.</td>
3343 </tr>
3344 <tr>
3345 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3346 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3347 collection is supported. If present, its value must be 6. This flag
3348 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3349 value 2.</td>
3350 </tr>
3351 </tbody>
3352</table>
3353
3354<p>Some important flag interactions:</p>
3355
3356<ul>
3357 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3358 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3359 2, then the resulting module has the <tt>Objective-C Garbage
3360 Collection</tt> flag set to 0.</li>
3361
3362 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3363 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3364</ul>
3365
3366</div>
3367
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3368</div>
3369
3370<!-- *********************************************************************** -->
3371<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3372 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3373</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3374<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3375<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3376<p>LLVM has a number of "magic" global variables that contain data that affect
3377code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3378of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3379section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3380by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3381
3382<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3383<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3384<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3385</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3386
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3387<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3388
3389<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3390href="#linkage_appending">appending linkage</a>. This array contains a list of
3391pointers to global variables and functions which may optionally have a pointer
3392cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3393
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3394<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3395<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3396@X = global i8 4
3397@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3398
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3399@llvm.used = appending global [2 x i8*] [
3400 i8* @X,
3401 i8* bitcast (i32* @Y to i8*)
3402], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3403</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3404</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3405
3406<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]3407 compiler, assembler, and linker are required to treat the symbol as if there
3408 is a reference to the global that it cannot see. For example, if a variable
3409 has internal linkage and no references other than that from
3410 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3411 represent references from inline asms and other things the compiler cannot
3412 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3413
3414<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]3415 object file to prevent the assembler and linker from molesting the
3416 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3417
3418</div>
3419
3420<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3421<h3>
3422 <a name="intg_compiler_used">
3423 The '<tt>llvm.compiler.used</tt>' Global Variable
3424 </a>
3425</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3426
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3427<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3428
3429<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3430 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3431 touching the symbol. On targets that support it, this allows an intelligent
3432 linker to optimize references to the symbol without being impeded as it would
3433 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3434
3435<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]3436 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3437
3438</div>
3439
3440<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3441<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3442<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3443</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3444
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3445<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3446
3447<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3448<pre>
3449%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3450@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3451</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3452</div>
3453
3454<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3455 functions and associated priorities. The functions referenced by this array
3456 will be called in ascending order of priority (i.e. lowest first) when the
3457 module is loaded. The order of functions with the same priority is not
3458 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3459
3460</div>
3461
3462<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3463<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3464<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3465</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3466
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3467<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3468
3469<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3470<pre>
3471%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3472@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3473</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3474</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3475
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3476<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3477 and associated priorities. The functions referenced by this array will be
3478 called in descending order of priority (i.e. highest first) when the module
3479 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3480
3481</div>
3482
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3483</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3484
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3485<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3486<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3487<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3488
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3489<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3490
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491<p>The LLVM instruction set consists of several different classifications of
3492 instructions: <a href="#terminators">terminator
3493 instructions</a>, <a href="#binaryops">binary instructions</a>,
3494 <a href="#bitwiseops">bitwise binary instructions</a>,
3495 <a href="#memoryops">memory instructions</a>, and
3496 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3497
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3498<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3499<h3>
3500 <a name="terminators">Terminator Instructions</a>
3501</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3502
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3503<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3504
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3506 in a program ends with a "Terminator" instruction, which indicates which
3507 block should be executed after the current block is finished. These
3508 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3509 control flow, not values (the one exception being the
3510 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3511
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3512<p>The terminator instructions are:
3513 '<a href="#i_ret"><tt>ret</tt></a>',
3514 '<a href="#i_br"><tt>br</tt></a>',
3515 '<a href="#i_switch"><tt>switch</tt></a>',
3516 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3517 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3518 '<a href="#i_resume"><tt>resume</tt></a>', and
3519 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3520
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3521<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3522<h4>
3523 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3524</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3526<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3528<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3529<pre>
3530 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]3531 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3532</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3536 a value) from a function back to the caller.</p>
3537
3538<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3539 value and then causes control flow, and one that just causes control flow to
3540 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3542<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3543<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3544 return value. The type of the return value must be a
3545 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3546
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3547<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3548 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3549 value or a return value with a type that does not match its type, or if it
3550 has a void return type and contains a '<tt>ret</tt>' instruction with a
3551 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3553<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3555 the calling function's context. If the caller is a
3556 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3557 instruction after the call. If the caller was an
3558 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3559 the beginning of the "normal" destination block. If the instruction returns
3560 a value, that value shall set the call or invoke instruction's return
3561 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3563<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3564<pre>
3565 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3566 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3567 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]3568</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3569
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3570</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3571<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3572<h4>
3573 <a name="i_br">'<tt>br</tt>' Instruction</a>
3574</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3576<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3578<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3579<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3580 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3581 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3582</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3584<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3586 different basic block in the current function. There are two forms of this
3587 instruction, corresponding to a conditional branch and an unconditional
3588 branch.</p>
3589
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3590<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3591<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3592 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3593 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3594 target.</p>
3595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3596<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3597<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3598 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3599 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3600 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3601
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3602<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3603<pre>
3604Test:
3605 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3606 br i1 %cond, label %IfEqual, label %IfUnequal
3607IfEqual:
3608 <a href="#i_ret">ret</a> i32 1
3609IfUnequal:
3610 <a href="#i_ret">ret</a> i32 0
3611</pre>
3612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3613</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3615<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3616<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3617 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3618</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3619
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3620<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3621
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3623<pre>
3624 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3625</pre>
3626
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3627<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3628<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]3629 several different places. It is a generalization of the '<tt>br</tt>'
3630 instruction, allowing a branch to occur to one of many possible
3631 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3634<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3636 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3637 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3638
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3639<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3640<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3642 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3643 transferred to the corresponding destination; otherwise, control flow is
3644 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3645
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3646<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3647<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648 <tt>switch</tt> instruction, this instruction may be code generated in
3649 different ways. For example, it could be generated as a series of chained
3650 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3651
3652<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3653<pre>
3654 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3655 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3656 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3657
3658 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3659 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3660
3661 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3662 switch i32 %val, label %otherwise [ i32 0, label %onzero
3663 i32 1, label %onone
3664 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3665</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3666
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3667</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3668
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3669
3670<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3671<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3672 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3673</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3674
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3675<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3676
3677<h5>Syntax:</h5>
3678<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3679 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]3680</pre>
3681
3682<h5>Overview:</h5>
3683
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3684<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3685 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3686 "<tt>address</tt>". Address must be derived from a <a
3687 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3688
3689<h5>Arguments:</h5>
3690
3691<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3692 rest of the arguments indicate the full set of possible destinations that the
3693 address may point to. Blocks are allowed to occur multiple times in the
3694 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3695
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3696<p>This destination list is required so that dataflow analysis has an accurate
3697 understanding of the CFG.</p>
3698
3699<h5>Semantics:</h5>
3700
3701<p>Control transfers to the block specified in the address argument. All
3702 possible destination blocks must be listed in the label list, otherwise this
3703 instruction has undefined behavior. This implies that jumps to labels
3704 defined in other functions have undefined behavior as well.</p>
3705
3706<h5>Implementation:</h5>
3707
3708<p>This is typically implemented with a jump through a register.</p>
3709
3710<h5>Example:</h5>
3711<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3712 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3713</pre>
3714
3715</div>
3716
3717
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3718<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3719<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3720 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3721</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3723<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3725<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3726<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3727 &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]3728 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3729</pre>
3730
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3731<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3732<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3733 function, with the possibility of control flow transfer to either the
3734 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3735 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3736 control flow will return to the "normal" label. If the callee (or any
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3737 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3738 instruction or other exception handling mechanism, control is interrupted and
3739 continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3740
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3741<p>The '<tt>exception</tt>' label is a
3742 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3743 exception. As such, '<tt>exception</tt>' label is required to have the
3744 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3745 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3746 happens, as its first non-PHI instruction. The restrictions on the
3747 "<tt>landingpad</tt>" instruction's tightly couples it to the
3748 "<tt>invoke</tt>" instruction, so that the important information contained
3749 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3750 code motion.</p>
3751
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3752<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3753<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3755<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3757 convention</a> the call should use. If none is specified, the call
3758 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3759
3760 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3762 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3763
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3764 <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]3765 function value being invoked. In most cases, this is a direct function
3766 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3767 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3768
3769 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3770 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3771
3772 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3773 signature argument types and parameter attributes. All arguments must be
3774 of <a href="#t_firstclass">first class</a> type. If the function
3775 signature indicates the function accepts a variable number of arguments,
3776 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3777
3778 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3779 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3780
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3781 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3782 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3783 handling mechanism.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3784
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3785 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3787 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3788</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3789
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3790<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791<p>This instruction is designed to operate as a standard
3792 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3793 primary difference is that it establishes an association with a label, which
3794 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3795
3796<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3798 exception. Additionally, this is important for implementation of
3799 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3801<p>For the purposes of the SSA form, the definition of the value returned by the
3802 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3803 block to the "normal" label. If the callee unwinds then no return value is
3804 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3806<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3807<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3808 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3809 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3810 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3811 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3812</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3813
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3815
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3816 <!-- _______________________________________________________________________ -->
3817
3818<h4>
3819 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3820</h4>
3821
3822<div>
3823
3824<h5>Syntax:</h5>
3825<pre>
3826 resume &lt;type&gt; &lt;value&gt;
3827</pre>
3828
3829<h5>Overview:</h5>
3830<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3831 successors.</p>
3832
3833<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3834<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3835 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3836 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3837
3838<h5>Semantics:</h5>
3839<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3840 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3841 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3842
3843<h5>Example:</h5>
3844<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3845 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3846</pre>
3847
3848</div>
3849
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3850<!-- _______________________________________________________________________ -->
3851
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3852<h4>
3853 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3854</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3855
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3856<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3857
3858<h5>Syntax:</h5>
3859<pre>
3860 unreachable
3861</pre>
3862
3863<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3864<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865 instruction is used to inform the optimizer that a particular portion of the
3866 code is not reachable. This can be used to indicate that the code after a
3867 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3868
3869<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3870<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3871
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3872</div>
3873
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3874</div>
3875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3876<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3877<h3>
3878 <a name="binaryops">Binary Operations</a>
3879</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3881<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882
3883<p>Binary operators are used to do most of the computation in a program. They
3884 require two operands of the same type, execute an operation on them, and
3885 produce a single value. The operands might represent multiple data, as is
3886 the case with the <a href="#t_vector">vector</a> data type. The result value
3887 has the same type as its operands.</p>
3888
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3889<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3891<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3892<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3893 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3894</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3895
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3896<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3898<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3899<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3900 &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]3901 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3902 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3903 &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]3904</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3907<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3910<p>The two arguments to the '<tt>add</tt>' instruction must
3911 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3912 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3914<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3915<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3916
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3917<p>If the sum has unsigned overflow, the result returned is the mathematical
3918 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]3919
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920<p>Because LLVM integers use a two's complement representation, this instruction
3921 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3922
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3923<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3924 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3925 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3926 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3927 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3929<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3930<pre>
3931 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3932</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3934</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3936<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3937<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3938 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3939</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3940
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3941<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3942
3943<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3944<pre>
3945 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3946</pre>
3947
3948<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3949<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3950
3951<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3952<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3954 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3955
3956<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3957<p>The value produced is the floating point sum of the two operands.</p>
3958
3959<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3960<pre>
3961 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3962</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3963
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3964</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3965
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3966<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3967<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3968 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3969</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3970
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3971<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3973<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3974<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3975 &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]3976 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3977 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3978 &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]3979</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3981<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3982<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3983 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3984
3985<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3986 '<tt>neg</tt>' instruction present in most other intermediate
3987 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3989<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3990<p>The two arguments to the '<tt>sub</tt>' instruction must
3991 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3992 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3994<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3995<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3996
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3997<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3999 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4000
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4001<p>Because LLVM integers use a two's complement representation, this instruction
4002 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4003
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4004<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4005 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4006 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4007 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]4008 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4009
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4010<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]4011<pre>
4012 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4013 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4014</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4015
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4016</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4017
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4018<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4019<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4020 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4021</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4022
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4023<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4024
4025<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4026<pre>
4027 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4028</pre>
4029
4030<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4031<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4033
4034<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4035 '<tt>fneg</tt>' instruction present in most other intermediate
4036 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4037
4038<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]4039<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4041 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4042
4043<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4044<p>The value produced is the floating point difference of the two operands.</p>
4045
4046<h5>Example:</h5>
4047<pre>
4048 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
4049 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
4050</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4051
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4052</div>
4053
4054<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4055<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4056 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4057</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4058
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4059<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4060
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4061<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4063 &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]4064 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4065 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4066 &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]4067</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4069<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4071
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4072<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073<p>The two arguments to the '<tt>mul</tt>' instruction must
4074 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4075 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4076
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4077<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4078<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4079
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4080<p>If the result of the multiplication has unsigned overflow, the result
4081 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
4082 width of the result.</p>
4083
4084<p>Because LLVM integers use a two's complement representation, and the result
4085 is the same width as the operands, this instruction returns the correct
4086 result for both signed and unsigned integers. If a full product
4087 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
4088 be sign-extended or zero-extended as appropriate to the width of the full
4089 product.</p>
4090
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]4091<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
4092 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
4093 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4094 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]4095 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4096
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4097<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4098<pre>
4099 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4100</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4101
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4102</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4103
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4104<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4105<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4106 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4107</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4108
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4109<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4110
4111<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4112<pre>
4113 &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]4114</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4115
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4116<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4117<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4118
4119<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4120<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4121 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4122 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4123
4124<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4125<p>The value produced is the floating point product of the two operands.</p>
4126
4127<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128<pre>
4129 &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]4130</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4131
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4132</div>
4133
4134<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4135<h4>
4136 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4137</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4138
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4139<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4140
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4141<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4142<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4143 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4144 &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]4145</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4146
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4147<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4148<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4149
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4150<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4151<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4152 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4153 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4154
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4155<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4156<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4157
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4158<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4159 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4160
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4161<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4162
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4163<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4164 <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]4165 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4166
4167
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4168<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4169<pre>
4170 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4171</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4172
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4173</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4174
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4175<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4176<h4>
4177 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4178</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4180<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4181
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4182<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4183<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4184 &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]4185 &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]4186</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4187
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4188<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4190
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4191<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4192<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4193 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4194 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4195
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4196<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4197<p>The value produced is the signed integer quotient of the two operands rounded
4198 towards zero.</p>
4199
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4200<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4201 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4202
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4203<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4204 undefined behavior; this is a rare case, but can occur, for example, by doing
4205 a 32-bit division of -2147483648 by -1.</p>
4206
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]4207<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4208 <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]4209 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4210
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4211<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212<pre>
4213 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4214</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4215
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4216</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4217
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4218<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4219<h4>
4220 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4221</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4223<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4224
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4225<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4226<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4227 &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]4228</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4229
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230<h5>Overview:</h5>
4231<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4232
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4233<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4234<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4236 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4237
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4238<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4239<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4240
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4241<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4242<pre>
4243 &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]4244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4246</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4247
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4248<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4249<h4>
4250 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4251</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4252
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4253<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4255<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4256<pre>
4257 &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]4258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4260<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4261<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4262 division of its two arguments.</p>
4263
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4264<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4265<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4267 values. Both arguments must have identical types.</p>
4268
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4269<h5>Semantics:</h5>
4270<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271 This instruction always performs an unsigned division to get the
4272 remainder.</p>
4273
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4274<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4275 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4276
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4277<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4279<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4280<pre>
4281 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4282</pre>
4283
4284</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4285
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4286<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4287<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4288 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4289</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4290
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4291<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4292
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4293<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4294<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4295 &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]4296</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4297
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4298<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4299<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4300 division of its two operands. This instruction can also take
4301 <a href="#t_vector">vector</a> versions of the values in which case the
4302 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]4303
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4304<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4305<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4307 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4308
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4309<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4310<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4311 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4312 <i>modulo</i> operator (where the result is either zero or has the same sign
4313 as the divisor, <tt>op2</tt>) of a value.
4314 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4315 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4316 Math Forum</a>. For a table of how this is implemented in various languages,
4317 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4318 Wikipedia: modulo operation</a>.</p>
4319
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4320<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4321 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4322
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4323<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324 Overflow also leads to undefined behavior; this is a rare case, but can
4325 occur, for example, by taking the remainder of a 32-bit division of
4326 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4327 lets srem be implemented using instructions that return both the result of
4328 the division and the remainder.)</p>
4329
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4330<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331<pre>
4332 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4333</pre>
4334
4335</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4336
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4337<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4338<h4>
4339 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4340</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4341
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4342<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4343
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4344<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4345<pre>
4346 &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]4347</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4349<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4350<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4351 its two operands.</p>
4352
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4353<h5>Arguments:</h5>
4354<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4356 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4357
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4358<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359<p>This instruction returns the <i>remainder</i> of a division. The remainder
4360 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4361
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4362<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4363<pre>
4364 &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]4365</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4367</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4368
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4369</div>
4370
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4371<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4372<h3>
4373 <a name="bitwiseops">Bitwise Binary Operations</a>
4374</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4375
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4376<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377
4378<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4379 program. They are generally very efficient instructions and can commonly be
4380 strength reduced from other instructions. They require two operands of the
4381 same type, execute an operation on them, and produce a single value. The
4382 resulting value is the same type as its operands.</p>
4383
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4384<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4385<h4>
4386 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4387</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4389<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4390
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4391<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4392<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4393 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4394 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4395 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4396 &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]4397</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4398
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4399<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4401 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4402
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4403<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4404<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4405 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4406 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4407
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4408<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4409<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4410 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4411 is (statically or dynamically) negative or equal to or larger than the number
4412 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4413 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4414 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4415
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4416<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4417 <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]4418 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4419 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4420 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4421 they would if the shift were expressed as a mul instruction with the same
4422 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4423
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424<h5>Example:</h5>
4425<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4426 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4427 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4428 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4429 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4430 &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]4431</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4432
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4433</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4434
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4435<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4436<h4>
4437 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4438</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4439
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4440<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4442<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4443<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4444 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4445 &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]4446</pre>
4447
4448<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4449<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4450 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4451
4452<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4453<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4455 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4456
4457<h5>Semantics:</h5>
4458<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4459 significant bits of the result will be filled with zero bits after the shift.
4460 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4461 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4462 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4463 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4464
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4465<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4466 <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]4467 shifted out are non-zero.</p>
4468
4469
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4470<h5>Example:</h5>
4471<pre>
4472 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4473 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4474 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4475 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4476 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4477 &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]4478</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4480</div>
4481
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4482<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4483<h4>
4484 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4485</h4>
4486
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4487<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4488
4489<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4491 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4492 &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]4493</pre>
4494
4495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4496<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4497 operand shifted to the right a specified number of bits with sign
4498 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4499
4500<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4501<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4502 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4503 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4504
4505<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4506<p>This instruction always performs an arithmetic shift right operation, The
4507 most significant bits of the result will be filled with the sign bit
4508 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4509 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4510 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4511 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4512
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4513<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4514 <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]4515 shifted out are non-zero.</p>
4516
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4517<h5>Example:</h5>
4518<pre>
4519 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4520 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4521 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4522 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4523 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4524 &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]4525</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4526
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4527</div>
4528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4529<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4530<h4>
4531 <a name="i_and">'<tt>and</tt>' Instruction</a>
4532</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4533
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4534<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4535
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4536<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4537<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4538 &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]4539</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4540
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4541<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4543 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4544
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4545<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4546<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4547 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4548 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4549
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4550<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4551<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4552
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4553<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4554 <tbody>
4555 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4556 <th>In0</th>
4557 <th>In1</th>
4558 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4559 </tr>
4560 <tr>
4561 <td>0</td>
4562 <td>0</td>
4563 <td>0</td>
4564 </tr>
4565 <tr>
4566 <td>0</td>
4567 <td>1</td>
4568 <td>0</td>
4569 </tr>
4570 <tr>
4571 <td>1</td>
4572 <td>0</td>
4573 <td>0</td>
4574 </tr>
4575 <tr>
4576 <td>1</td>
4577 <td>1</td>
4578 <td>1</td>
4579 </tr>
4580 </tbody>
4581</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4582
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4583<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4584<pre>
4585 &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]4586 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4587 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4588</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4589</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4590<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4591<h4>
4592 <a name="i_or">'<tt>or</tt>' Instruction</a>
4593</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4594
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4595<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596
4597<h5>Syntax:</h5>
4598<pre>
4599 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4600</pre>
4601
4602<h5>Overview:</h5>
4603<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4604 two operands.</p>
4605
4606<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4607<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4608 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4609 values. Both arguments must have identical types.</p>
4610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4611<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4612<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4614<table border="1" cellspacing="0" cellpadding="4">
4615 <tbody>
4616 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4617 <th>In0</th>
4618 <th>In1</th>
4619 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4620 </tr>
4621 <tr>
4622 <td>0</td>
4623 <td>0</td>
4624 <td>0</td>
4625 </tr>
4626 <tr>
4627 <td>0</td>
4628 <td>1</td>
4629 <td>1</td>
4630 </tr>
4631 <tr>
4632 <td>1</td>
4633 <td>0</td>
4634 <td>1</td>
4635 </tr>
4636 <tr>
4637 <td>1</td>
4638 <td>1</td>
4639 <td>1</td>
4640 </tr>
4641 </tbody>
4642</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4643
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4644<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645<pre>
4646 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4647 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4648 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4649</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4650
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4651</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4652
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4653<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4654<h4>
4655 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4656</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4657
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4658<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4660<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4661<pre>
4662 &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]4663</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4665<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4667 its two operands. The <tt>xor</tt> is used to implement the "one's
4668 complement" operation, which is the "~" operator in C.</p>
4669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4670<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4671<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4673 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4675<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4676<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4678<table border="1" cellspacing="0" cellpadding="4">
4679 <tbody>
4680 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4681 <th>In0</th>
4682 <th>In1</th>
4683 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4684 </tr>
4685 <tr>
4686 <td>0</td>
4687 <td>0</td>
4688 <td>0</td>
4689 </tr>
4690 <tr>
4691 <td>0</td>
4692 <td>1</td>
4693 <td>1</td>
4694 </tr>
4695 <tr>
4696 <td>1</td>
4697 <td>0</td>
4698 <td>1</td>
4699 </tr>
4700 <tr>
4701 <td>1</td>
4702 <td>1</td>
4703 <td>0</td>
4704 </tr>
4705 </tbody>
4706</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4708<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709<pre>
4710 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4711 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4712 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4713 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4714</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4716</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4718</div>
4719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4720<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4721<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4722 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4723</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4724
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4725<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4726
4727<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4728 target-independent manner. These instructions cover the element-access and
4729 vector-specific operations needed to process vectors effectively. While LLVM
4730 does directly support these vector operations, many sophisticated algorithms
4731 will want to use target-specific intrinsics to take full advantage of a
4732 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4733
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4734<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4735<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4736 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4737</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4738
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4739<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4740
4741<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4742<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4743 &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]4744</pre>
4745
4746<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4747<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4748 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4749
4750
4751<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4753 of <a href="#t_vector">vector</a> type. The second operand is an index
4754 indicating the position from which to extract the element. The index may be
4755 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4756
4757<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758<p>The result is a scalar of the same type as the element type of
4759 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4760 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4761 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4762
4763<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4764<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4765 &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]4766</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4767
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4768</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4769
4770<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4771<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4772 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4773</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4774
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4775<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4776
4777<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4778<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4779 &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]4780</pre>
4781
4782<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4783<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4784 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4785
4786<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4787<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4788 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4789 whose type must equal the element type of the first operand. The third
4790 operand is an index indicating the position at which to insert the value.
4791 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4792
4793<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4794<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4795 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4796 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4797 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4798
4799<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4800<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4801 &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]4802</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4803
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4804</div>
4805
4806<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4807<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4808 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4809</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4811<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4812
4813<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4814<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4815 &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]4816</pre>
4817
4818<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4819<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4820 from two input vectors, returning a vector with the same element type as the
4821 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4822
4823<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4824<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
Duncan Sandsb5a1bf42012-06-14 14:58:28 +0000[diff] [blame]4825 with the same type. The third argument is a shuffle mask whose
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4826 element type is always 'i32'. The result of the instruction is a vector
4827 whose length is the same as the shuffle mask and whose element type is the
4828 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4830<p>The shuffle mask operand is required to be a constant vector with either
4831 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4832
4833<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834<p>The elements of the two input vectors are numbered from left to right across
4835 both of the vectors. The shuffle mask operand specifies, for each element of
4836 the result vector, which element of the two input vectors the result element
4837 gets. The element selector may be undef (meaning "don't care") and the
4838 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4839
4840<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4841<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4842 &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]4843 &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]4844 &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]4845 &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]4846 &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]4847 &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]4848 &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]4849 &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]4850</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4851
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4852</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4853
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4854</div>
4855
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4856<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4857<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4858 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4859</h3>
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
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4863<p>LLVM supports several instructions for working with
4864 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4865
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4866<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4867<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4868 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4869</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4870
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4871<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4872
4873<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4874<pre>
4875 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4876</pre>
4877
4878<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4879<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4880 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4881
4882<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4884 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4885 <a href="#t_array">array</a> type. The operands are constant indices to
4886 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4888 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4889 <ul>
4890 <li>Since the value being indexed is not a pointer, the first index is
4891 omitted and assumed to be zero.</li>
4892 <li>At least one index must be specified.</li>
4893 <li>Not only struct indices but also array indices must be in
4894 bounds.</li>
4895 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4896
4897<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898<p>The result is the value at the position in the aggregate specified by the
4899 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4900
4901<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4902<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4903 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4904</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4906</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4907
4908<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4909<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4910 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4911</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4912
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4913<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4914
4915<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4916<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4917 &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]4918</pre>
4919
4920<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4921<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4922 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4923
4924<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4925<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4926 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4927 <a href="#t_array">array</a> type. The second operand is a first-class
4928 value to insert. The following operands are constant indices indicating
4929 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]4930 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931 value to insert must have the same type as the value identified by the
4932 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4933
4934<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4935<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4936 that of <tt>val</tt> except that the value at the position specified by the
4937 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4938
4939<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4940<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4941 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4942 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4943 %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]4944</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4945
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4946</div>
4947
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4948</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4949
4950<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4951<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4952 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4953</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4954
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4955<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4956
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4957<p>A key design point of an SSA-based representation is how it represents
4958 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4959 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4961
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4962<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4963<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4964 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4965</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4966
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4967<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4969<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4970<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4971 &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]4972</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4973
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4974<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4975<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976 currently executing function, to be automatically released when this function
4977 returns to its caller. The object is always allocated in the generic address
4978 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4980<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4981<p>The '<tt>alloca</tt>' instruction
4982 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4983 runtime stack, returning a pointer of the appropriate type to the program.
4984 If "NumElements" is specified, it is the number of elements allocated,
4985 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4986 specified, the value result of the allocation is guaranteed to be aligned to
4987 at least that boundary. If not specified, or if zero, the target can choose
4988 to align the allocation on any convenient boundary compatible with the
4989 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4990
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4991<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4992
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4993<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4994<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4995 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4996 memory is automatically released when the function returns. The
4997 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4998 variables that must have an address available. When the function returns
4999 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]5000 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]5001 reclaimed. Allocating zero bytes is legal, but the result is undefined.
5002 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewycky75d05e62012-03-18 09:35:50 +0000[diff] [blame]5003 not specified.</p>
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]5004
5005<p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]5006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5007<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]5008<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]5009 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
5010 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
5011 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
5012 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5013</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5014
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5015</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]5016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5017<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5018<h4>
5019 <a name="i_load">'<tt>load</tt>' Instruction</a>
5020</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5022<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5023
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5024<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025<pre>
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]5026 &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]5027 &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]5028 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5029</pre>
5030
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5031<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5032<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5033
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5034<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5035<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
5036 from which to load. The pointer must point to
5037 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
5038 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]5039 number or order of execution of this <tt>load</tt> with other <a
5040 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5041
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]5042<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
5043 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5044 argument. The <code>release</code> and <code>acq_rel</code> orderings are
5045 not valid on <code>load</code> instructions. Atomic loads produce <a
5046 href="#memorymodel">defined</a> results when they may see multiple atomic
5047 stores. The type of the pointee must be an integer type whose bit width
5048 is a power of two greater than or equal to eight and less than or equal
5049 to a target-specific size limit. <code>align</code> must be explicitly
5050 specified on atomic loads, and the load has undefined behavior if the
5051 alignment is not set to a value which is at least the size in bytes of
5052 the pointee. <code>!nontemporal</code> does not have any defined semantics
5053 for atomic loads.</p>
5054
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5055<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5056 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]5057 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5058 alignment for the target. It is the responsibility of the code emitter to
5059 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5060 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5061 produce less efficient code. An alignment of 1 is always safe.</p>
5062
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5063<p>The optional <tt>!nontemporal</tt> metadata must reference a single
5064 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5065 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]5066 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
5067 and code generator that this load is not expected to be reused in the cache.
5068 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5069 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5070
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]5071<p>The optional <tt>!invariant.load</tt> metadata must reference a single
5072 metatadata name &lt;index&gt; corresponding to a metadata node with no
5073 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
5074 instruction tells the optimizer and code generator that this load address
5075 points to memory which does not change value during program execution.
5076 The optimizer may then move this load around, for example, by hoisting it
5077 out of loops using loop invariant code motion.</p>
5078
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5079<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<p>The location of memory pointed to is loaded. If the value being loaded is of
5081 scalar type then the number of bytes read does not exceed the minimum number
5082 of bytes needed to hold all bits of the type. For example, loading an
5083 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
5084 <tt>i20</tt> with a size that is not an integral number of bytes, the result
5085 is undefined if the value was not originally written using a store of the
5086 same type.</p>
5087
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5088<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089<pre>
5090 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
5091 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5092 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5093</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5094
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5095</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5096
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5097<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5098<h4>
5099 <a name="i_store">'<tt>store</tt>' Instruction</a>
5100</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5101
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5102<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5103
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5104<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5105<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5106 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>
5107 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]5108</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5110<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5111<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5112
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5113<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5114<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5115 and an address at which to store it. The type of the
5116 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5117 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]5118 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5119 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5120 order of execution of this <tt>store</tt> with other <a
5121 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]5123<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5124 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5125 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5126 valid on <code>store</code> instructions. Atomic loads produce <a
5127 href="#memorymodel">defined</a> results when they may see multiple atomic
5128 stores. The type of the pointee must be an integer type whose bit width
5129 is a power of two greater than or equal to eight and less than or equal
5130 to a target-specific size limit. <code>align</code> must be explicitly
5131 specified on atomic stores, and the store has undefined behavior if the
5132 alignment is not set to a value which is at least the size in bytes of
5133 the pointee. <code>!nontemporal</code> does not have any defined semantics
5134 for atomic stores.</p>
5135
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5136<p>The optional constant "align" argument specifies the alignment of the
5137 operation (that is, the alignment of the memory address). A value of 0 or an
5138 omitted "align" argument means that the operation has the preferential
5139 alignment for the target. It is the responsibility of the code emitter to
5140 ensure that the alignment information is correct. Overestimating the
5141 alignment results in an undefined behavior. Underestimating the alignment may
5142 produce less efficient code. An alignment of 1 is always safe.</p>
5143
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5144<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5145 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5146 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5147 instruction tells the optimizer and code generator that this load is
5148 not expected to be reused in the cache. The code generator may
5149 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5150 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5151
5152
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5153<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5154<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5155 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5156 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5157 does not exceed the minimum number of bytes needed to hold all bits of the
5158 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5159 writing a value of a type like <tt>i20</tt> with a size that is not an
5160 integral number of bytes, it is unspecified what happens to the extra bits
5161 that do not belong to the type, but they will typically be overwritten.</p>
5162
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5163<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5164<pre>
5165 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]5166 store i32 3, i32* %ptr <i>; yields {void}</i>
5167 %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]5168</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5169
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5170</div>
5171
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5172<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5173<h4>
5174<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5175</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5176
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5177<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5178
5179<h5>Syntax:</h5>
5180<pre>
5181 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5182</pre>
5183
5184<h5>Overview:</h5>
5185<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5186between operations.</p>
5187
5188<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5189href="#ordering">ordering</a> argument which defines what
5190<i>synchronizes-with</i> edges they add. They can only be given
5191<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5192<code>seq_cst</code> orderings.</p>
5193
5194<h5>Semantics:</h5>
5195<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5196semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5197<code>acquire</code> ordering semantics if and only if there exist atomic
5198operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5199<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5200<var>X</var> modifies <var>M</var> (either directly or through some side effect
5201of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5202<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5203<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5204than an explicit <code>fence</code>, one (but not both) of the atomic operations
5205<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5206<code>acquire</code> (resp.) ordering constraint and still
5207<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5208<i>happens-before</i> edge.</p>
5209
5210<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5211having both <code>acquire</code> and <code>release</code> semantics specified
5212above, participates in the global program order of other <code>seq_cst</code>
5213operations and/or fences.</p>
5214
5215<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5216specifies that the fence only synchronizes with other fences in the same
5217thread. (This is useful for interacting with signal handlers.)</p>
5218
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5219<h5>Example:</h5>
5220<pre>
5221 fence acquire <i>; yields {void}</i>
5222 fence singlethread seq_cst <i>; yields {void}</i>
5223</pre>
5224
5225</div>
5226
5227<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5228<h4>
5229<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5230</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5231
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5232<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5233
5234<h5>Syntax:</h5>
5235<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5236 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]5237</pre>
5238
5239<h5>Overview:</h5>
5240<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5241It loads a value in memory and compares it to a given value. If they are
5242equal, it stores a new value into the memory.</p>
5243
5244<h5>Arguments:</h5>
5245<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5246address to operate on, a value to compare to the value currently be at that
5247address, and a new value to place at that address if the compared values are
5248equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5249bit width is a power of two greater than or equal to eight and less than
5250or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5251'<var>&lt;new&gt;</var>' must have the same type, and the type of
5252'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5253<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5254optimizer is not allowed to modify the number or order of execution
5255of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5256operations</a>.</p>
5257
5258<!-- FIXME: Extend allowed types. -->
5259
5260<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5261<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5262
5263<p>The optional "<code>singlethread</code>" argument declares that the
5264<code>cmpxchg</code> is only atomic with respect to code (usually signal
5265handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5266cmpxchg is atomic with respect to all other code in the system.</p>
5267
5268<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5269the size in memory of the operand.
5270
5271<h5>Semantics:</h5>
5272<p>The contents of memory at the location specified by the
5273'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5274'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5275'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5276is returned.
5277
5278<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5279purpose of identifying <a href="#release_sequence">release sequences</a>. A
5280failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5281parameter determined by dropping any <code>release</code> part of the
5282<code>cmpxchg</code>'s ordering.</p>
5283
5284<!--
5285FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5286optimization work on ARM.)
5287
5288FIXME: Is a weaker ordering constraint on failure helpful in practice?
5289-->
5290
5291<h5>Example:</h5>
5292<pre>
5293entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5294 %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]5295 <a href="#i_br">br</a> label %loop
5296
5297loop:
5298 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5299 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5300 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5301 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5302 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5303
5304done:
5305 ...
5306</pre>
5307
5308</div>
5309
5310<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5311<h4>
5312<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5313</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5314
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5315<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5316
5317<h5>Syntax:</h5>
5318<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5319 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]5320</pre>
5321
5322<h5>Overview:</h5>
5323<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5324
5325<h5>Arguments:</h5>
5326<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5327operation to apply, an address whose value to modify, an argument to the
5328operation. The operation must be one of the following keywords:</p>
5329<ul>
5330 <li>xchg</li>
5331 <li>add</li>
5332 <li>sub</li>
5333 <li>and</li>
5334 <li>nand</li>
5335 <li>or</li>
5336 <li>xor</li>
5337 <li>max</li>
5338 <li>min</li>
5339 <li>umax</li>
5340 <li>umin</li>
5341</ul>
5342
5343<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5344bit width is a power of two greater than or equal to eight and less than
5345or equal to a target-specific size limit. The type of the
5346'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5347If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5348optimizer is not allowed to modify the number or order of execution of this
5349<code>atomicrmw</code> with other <a href="#volatile">volatile
5350 operations</a>.</p>
5351
5352<!-- FIXME: Extend allowed types. -->
5353
5354<h5>Semantics:</h5>
5355<p>The contents of memory at the location specified by the
5356'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5357back. The original value at the location is returned. The modification is
5358specified by the <var>operation</var> argument:</p>
5359
5360<ul>
5361 <li>xchg: <code>*ptr = val</code></li>
5362 <li>add: <code>*ptr = *ptr + val</code></li>
5363 <li>sub: <code>*ptr = *ptr - val</code></li>
5364 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5365 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5366 <li>or: <code>*ptr = *ptr | val</code></li>
5367 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5368 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5369 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5370 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5371 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5372</ul>
5373
5374<h5>Example:</h5>
5375<pre>
5376 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5377</pre>
5378
5379</div>
5380
5381<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5382<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5383 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5384</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5385
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5386<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5387
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5388<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5389<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5390 &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]5391 &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]5392 &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]5393</pre>
5394
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5395<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5396<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5397 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5398 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5399
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5400<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5401<p>The first argument is always a pointer or a vector of pointers,
5402 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5403 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5404 elements of the aggregate object are indexed. The interpretation of each
5405 index is dependent on the type being indexed into. The first index always
5406 indexes the pointer value given as the first argument, the second index
5407 indexes a value of the type pointed to (not necessarily the value directly
5408 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5409 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5410 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5411 can never be pointers, since that would require loading the pointer before
5412 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5413
5414<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]5415 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5416 integer <b>constants</b> are allowed. When indexing into an array, pointer
5417 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]5418 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5419
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5420<p>For example, let's consider a C code fragment and how it gets compiled to
5421 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5422
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5423<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5424struct RT {
5425 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5426 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5427 char C;
5428};
5429struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5430 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5431 double Y;
5432 struct RT Z;
5433};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5434
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5435int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5436 return &amp;s[1].Z.B[5][13];
5437}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5438</pre>
5439
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5440<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5441
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5442<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5443%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5444%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5445
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5446define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5447entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5448 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5449 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5450}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5451</pre>
5452
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5453<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5454<p>In the example above, the first index is indexing into the
5455 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5456 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5457 structure. The second index indexes into the third element of the structure,
5458 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5459 type, another structure. The third index indexes into the second element of
5460 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5461 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5462 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5463 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5464
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5465<p>Note that it is perfectly legal to index partially through a structure,
5466 returning a pointer to an inner element. Because of this, the LLVM code for
5467 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5468
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5469<pre class="doc_code">
5470define i32* @foo(%struct.ST* %s) {
5471 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5472 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5473 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5474 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5475 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5476 ret i32* %t5
5477}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5478</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5479
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5480<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5481 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5482 base pointer is not an <i>in bounds</i> address of an allocated object,
5483 or if any of the addresses that would be formed by successive addition of
5484 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5485 precise signed arithmetic are not an <i>in bounds</i> address of that
5486 allocated object. The <i>in bounds</i> addresses for an allocated object
5487 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5488 byte past the end.
5489 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5490 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5491
5492<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]5493 the base address with silently-wrapping two's complement arithmetic. If the
5494 offsets have a different width from the pointer, they are sign-extended or
5495 truncated to the width of the pointer. The result value of the
5496 <tt>getelementptr</tt> may be outside the object pointed to by the base
5497 pointer. The result value may not necessarily be used to access memory
5498 though, even if it happens to point into allocated storage. See the
5499 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5500 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5501
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5502<p>The getelementptr instruction is often confusing. For some more insight into
5503 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5504
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5505<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5506<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5507 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5508 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5509 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5510 %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]5511 <i>; yields i8*:eptr</i>
5512 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5513 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5514 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5515</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5516
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5517<p>In cases where the pointer argument is a vector of pointers, only a
5518 single index may be used, and the number of vector elements has to be
5519 the same. For example: </p>
5520<pre class="doc_code">
5521 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5522</pre>
5523
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5524</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5525
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5526</div>
5527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5528<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5529<h3>
5530 <a name="convertops">Conversion Operations</a>
5531</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5532
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5533<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5535<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536 which all take a single operand and a type. They perform various bit
5537 conversions on the operand.</p>
5538
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5539<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5540<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5541 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5542</h4>
5543
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5544<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5545
5546<h5>Syntax:</h5>
5547<pre>
5548 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5549</pre>
5550
5551<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5552<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5553 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5554
5555<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5556<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5557 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5558 of the same number of integers.
5559 The bit size of the <tt>value</tt> must be larger than
5560 the bit size of the destination type, <tt>ty2</tt>.
5561 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5562
5563<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5564<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5565 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5566 source size must be larger than the destination size, <tt>trunc</tt> cannot
5567 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5568
5569<h5>Example:</h5>
5570<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5571 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5572 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5573 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5574 %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]5575</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5576
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5577</div>
5578
5579<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5580<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5581 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5582</h4>
5583
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5584<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5585
5586<h5>Syntax:</h5>
5587<pre>
5588 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5589</pre>
5590
5591<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5592<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5593 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5594
5595
5596<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5597<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5598 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5599 of the same number of integers.
5600 The bit size of the <tt>value</tt> must be smaller than
5601 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5602 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5603
5604<h5>Semantics:</h5>
5605<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]5606 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5607
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5608<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]5609
5610<h5>Example:</h5>
5611<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5612 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5613 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5614 %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]5615</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5616
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5617</div>
5618
5619<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5620<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5621 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5622</h4>
5623
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5624<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5625
5626<h5>Syntax:</h5>
5627<pre>
5628 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5629</pre>
5630
5631<h5>Overview:</h5>
5632<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5633
5634<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5635<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5636 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5637 of the same number of integers.
5638 The bit size of the <tt>value</tt> must be smaller than
5639 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5640 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5641
5642<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5643<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5644 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5645 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5646
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5647<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]5648
5649<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5650<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5651 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5652 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5653 %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]5654</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5655
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5656</div>
5657
5658<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5659<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5660 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5661</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5662
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5663<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5664
5665<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5666<pre>
5667 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5668</pre>
5669
5670<h5>Overview:</h5>
5671<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5672 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5673
5674<h5>Arguments:</h5>
5675<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5677 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]5678 <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]5679 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5680
5681<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5682<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5683 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5684 <a href="#t_floating">floating point</a> type. If the value cannot fit
5685 within the destination type, <tt>ty2</tt>, then the results are
5686 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5687
5688<h5>Example:</h5>
5689<pre>
5690 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5691 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5692</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5694</div>
5695
5696<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5697<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5698 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5699</h4>
5700
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5701<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5702
5703<h5>Syntax:</h5>
5704<pre>
5705 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5706</pre>
5707
5708<h5>Overview:</h5>
5709<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]5710 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5711
5712<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5713<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5715 a <a href="#t_floating">floating point</a> type to cast it to. The source
5716 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5717
5718<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5719<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5720 <a href="#t_floating">floating point</a> type to a larger
5721 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5722 used to make a <i>no-op cast</i> because it always changes bits. Use
5723 <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]5724
5725<h5>Example:</h5>
5726<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5727 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5728 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5729</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5730
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5731</div>
5732
5733<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5734<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5735 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5736</h4>
5737
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5738<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5739
5740<h5>Syntax:</h5>
5741<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5742 &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]5743</pre>
5744
5745<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5746<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5747 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5748
5749<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5750<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5751 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5752 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5753 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5754 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5755
5756<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5757<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5758 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5759 towards zero) unsigned integer value. If the value cannot fit
5760 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5761
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5762<h5>Example:</h5>
5763<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5764 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5765 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5766 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5767</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5768
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5769</div>
5770
5771<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5772<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5773 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5774</h4>
5775
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5776<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5777
5778<h5>Syntax:</h5>
5779<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5780 &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]5781</pre>
5782
5783<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5784<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5785 <a href="#t_floating">floating point</a> <tt>value</tt> to
5786 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5787
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5788<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5789<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5790 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5791 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5792 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5793 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5794
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5795<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5796<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5797 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5798 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5799 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5800
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5801<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5802<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5803 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5804 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5805 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5806</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5808</div>
5809
5810<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5811<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5812 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5813</h4>
5814
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5815<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5816
5817<h5>Syntax:</h5>
5818<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5819 &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]5820</pre>
5821
5822<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5823<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5824 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5825
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5826<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5827<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]5828 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5829 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5830 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5831 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5832
5833<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5834<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5835 integer quantity and converts it to the corresponding floating point
5836 value. If the value cannot fit in the floating point value, the results are
5837 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5838
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5839<h5>Example:</h5>
5840<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5841 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5842 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5843</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5844
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5845</div>
5846
5847<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5848<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5849 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5850</h4>
5851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5852<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5853
5854<h5>Syntax:</h5>
5855<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5856 &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]5857</pre>
5858
5859<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5860<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5861 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5862
5863<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5864<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]5865 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5866 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5867 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5868 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5869
5870<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5871<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5872 quantity and converts it to the corresponding floating point value. If the
5873 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5874
5875<h5>Example:</h5>
5876<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5877 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5878 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5879</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5881</div>
5882
5883<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5884<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5885 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5886</h4>
5887
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5888<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5889
5890<h5>Syntax:</h5>
5891<pre>
5892 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5893</pre>
5894
5895<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5896<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5897 pointers <tt>value</tt> to
5898 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5899
5900<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5901<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5902 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5903 pointers, and a type to cast it to
5904 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5905 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5906
5907<h5>Semantics:</h5>
5908<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5909 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5910 truncating or zero extending that value to the size of the integer type. If
5911 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5912 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5913 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5914 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5915
5916<h5>Example:</h5>
5917<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5918 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5919 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5920 %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]5921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5923</div>
5924
5925<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5926<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5927 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5928</h4>
5929
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5930<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5931
5932<h5>Syntax:</h5>
5933<pre>
5934 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5935</pre>
5936
5937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5938<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5939 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5940
5941<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5942<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5943 value to cast, and a type to cast it to, which must be a
5944 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5945
5946<h5>Semantics:</h5>
5947<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5948 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5949 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5950 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5951 than the size of a pointer then a zero extension is done. If they are the
5952 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5953
5954<h5>Example:</h5>
5955<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5956 %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]5957 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5958 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5959 %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]5960</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5961
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5962</div>
5963
5964<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5965<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5966 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5967</h4>
5968
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5969<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5970
5971<h5>Syntax:</h5>
5972<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5973 &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]5974</pre>
5975
5976<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5977<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5978 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5979
5980<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5981<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5982 non-aggregate first class value, and a type to cast it to, which must also be
5983 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5984 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5985 identical. If the source type is a pointer, the destination type must also be
5986 a pointer. This instruction supports bitwise conversion of vectors to
5987 integers and to vectors of other types (as long as they have the same
5988 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5989
5990<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5991<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5993 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5994 stored to memory and read back as type <tt>ty2</tt>.
5995 Pointer (or vector of pointers) types may only be converted to other pointer
5996 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5997 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5998 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5999
6000<h5>Example:</h5>
6001<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6002 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6003 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]6004 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
6005 %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]6006</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6008</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6009
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6010</div>
6011
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6012<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6013<h3>
6014 <a name="otherops">Other Operations</a>
6015</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6016
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6017<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6018
6019<p>The instructions in this category are the "miscellaneous" instructions, which
6020 defy better classification.</p>
6021
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6022<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6023<h4>
6024 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
6025</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6026
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6027<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6028
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6029<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6030<pre>
6031 &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]6032</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6033
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6034<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6035<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]6036 boolean values based on comparison of its two integer, integer vector,
6037 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6039<h5>Arguments:</h5>
6040<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6041 the condition code indicating the kind of comparison to perform. It is not a
6042 value, just a keyword. The possible condition code are:</p>
6043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6044<ol>
6045 <li><tt>eq</tt>: equal</li>
6046 <li><tt>ne</tt>: not equal </li>
6047 <li><tt>ugt</tt>: unsigned greater than</li>
6048 <li><tt>uge</tt>: unsigned greater or equal</li>
6049 <li><tt>ult</tt>: unsigned less than</li>
6050 <li><tt>ule</tt>: unsigned less or equal</li>
6051 <li><tt>sgt</tt>: signed greater than</li>
6052 <li><tt>sge</tt>: signed greater or equal</li>
6053 <li><tt>slt</tt>: signed less than</li>
6054 <li><tt>sle</tt>: signed less or equal</li>
6055</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6056
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]6057<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
6059 typed. They must also be identical types.</p>
6060
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6061<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
6063 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6064 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]6065 result, as follows:</p>
6066
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6067<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6068 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6069 <tt>false</tt> otherwise. No sign interpretation is necessary or
6070 performed.</li>
6071
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6072 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6073 <tt>false</tt> otherwise. No sign interpretation is necessary or
6074 performed.</li>
6075
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6076 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6078
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6079 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6080 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6081 to <tt>op2</tt>.</li>
6082
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6083 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6084 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6085
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6086 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6087 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6088
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6089 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6090 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6091
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6092 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6093 <tt>true</tt> if <tt>op1</tt> is greater than or equal
6094 to <tt>op2</tt>.</li>
6095
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6096 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6097 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6098
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6099 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6100 <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]6101</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6102
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6103<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6104 values are compared as if they were integers.</p>
6105
6106<p>If the operands are integer vectors, then they are compared element by
6107 element. The result is an <tt>i1</tt> vector with the same number of elements
6108 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6109
6110<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6111<pre>
6112 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6113 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6114 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6115 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6116 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6117 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6118</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6119
6120<p>Note that the code generator does not yet support vector types with
6121 the <tt>icmp</tt> instruction.</p>
6122
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6123</div>
6124
6125<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6126<h4>
6127 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6128</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6129
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6130<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6131
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6132<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6133<pre>
6134 &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]6135</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6137<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6138<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6139 values based on comparison of its operands.</p>
6140
6141<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]6142(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6143
6144<p>If the operands are floating point vectors, then the result type is a vector
6145 of boolean with the same number of elements as the operands being
6146 compared.</p>
6147
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6148<h5>Arguments:</h5>
6149<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6150 the condition code indicating the kind of comparison to perform. It is not a
6151 value, just a keyword. The possible condition code are:</p>
6152
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6153<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6154 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6155 <li><tt>oeq</tt>: ordered and equal</li>
6156 <li><tt>ogt</tt>: ordered and greater than </li>
6157 <li><tt>oge</tt>: ordered and greater than or equal</li>
6158 <li><tt>olt</tt>: ordered and less than </li>
6159 <li><tt>ole</tt>: ordered and less than or equal</li>
6160 <li><tt>one</tt>: ordered and not equal</li>
6161 <li><tt>ord</tt>: ordered (no nans)</li>
6162 <li><tt>ueq</tt>: unordered or equal</li>
6163 <li><tt>ugt</tt>: unordered or greater than </li>
6164 <li><tt>uge</tt>: unordered or greater than or equal</li>
6165 <li><tt>ult</tt>: unordered or less than </li>
6166 <li><tt>ule</tt>: unordered or less than or equal</li>
6167 <li><tt>une</tt>: unordered or not equal</li>
6168 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6169 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6170</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6171
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6172<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173 <i>unordered</i> means that either operand may be a QNAN.</p>
6174
6175<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6176 a <a href="#t_floating">floating point</a> type or
6177 a <a href="#t_vector">vector</a> of floating point type. They must have
6178 identical types.</p>
6179
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6180<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]6181<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6182 according to the condition code given as <tt>cond</tt>. If the operands are
6183 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6184 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6185 follows:</p>
6186
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6187<ol>
6188 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6189
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6190 <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]6191 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6192
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6193 <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]6194 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6195
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6196 <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]6197 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6198
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6199 <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]6200 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6201
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6202 <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]6203 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6204
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6205 <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]6206 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6207
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6208 <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]6209
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6210 <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]6211 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6212
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6213 <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]6214 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6215
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6216 <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]6217 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6218
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6219 <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]6220 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6221
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6222 <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]6223 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6224
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6225 <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]6226 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6227
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6228 <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]6229
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6230 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6231</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6232
6233<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6234<pre>
6235 &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]6236 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6237 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6238 &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]6239</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6240
6241<p>Note that the code generator does not yet support vector types with
6242 the <tt>fcmp</tt> instruction.</p>
6243
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6244</div>
6245
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6246<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6247<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6248 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6249</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6250
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6251<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6252
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6253<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6254<pre>
6255 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6256</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6257
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6258<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6259<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6260 SSA graph representing the function.</p>
6261
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6262<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6263<p>The type of the incoming values is specified with the first type field. After
6264 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6265 one pair for each predecessor basic block of the current block. Only values
6266 of <a href="#t_firstclass">first class</a> type may be used as the value
6267 arguments to the PHI node. Only labels may be used as the label
6268 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6269
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6270<p>There must be no non-phi instructions between the start of a basic block and
6271 the PHI instructions: i.e. PHI instructions must be first in a basic
6272 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6273
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6274<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6275 occur on the edge from the corresponding predecessor block to the current
6276 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6277 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]6278
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6279<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6280<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6281 specified by the pair corresponding to the predecessor basic block that
6282 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6283
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6284<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6285<pre>
6286Loop: ; Infinite loop that counts from 0 on up...
6287 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6288 %nextindvar = add i32 %indvar, 1
6289 br label %Loop
6290</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6291
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6292</div>
6293
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6294<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6295<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6296 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6297</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6298
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6299<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6300
6301<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6302<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6303 &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>
6304
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6305 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6306</pre>
6307
6308<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6309<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6310 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6311
6312
6313<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6314<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6315 values indicating the condition, and two values of the
6316 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6317 vectors and the condition is a scalar, then entire vectors are selected, not
6318 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6319
6320<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6321<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6322 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6323
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6324<p>If the condition is a vector of i1, then the value arguments must be vectors
6325 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6326
6327<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6328<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6329 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6330</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6331
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6332</div>
6333
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6334<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6335<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6336 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6337</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6338
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6339<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6340
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6341<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6342<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6343 &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]6344</pre>
6345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6346<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6347<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6349<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6350<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6351
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6352<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6353 <li>The optional "tail" marker indicates that the callee function does not
6354 access any allocas or varargs in the caller. Note that calls may be
6355 marked "tail" even if they do not occur before
6356 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6357 present, the function call is eligible for tail call optimization,
6358 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6359 optimized into a jump</a>. The code generator may optimize calls marked
6360 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6361 sibling call optimization</a> when the caller and callee have
6362 matching signatures, or 2) forced tail call optimization when the
6363 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6364 <ul>
6365 <li>Caller and callee both have the calling
6366 convention <tt>fastcc</tt>.</li>
6367 <li>The call is in tail position (ret immediately follows call and ret
6368 uses value of call or is void).</li>
6369 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6370 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6371 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6372 constraints are met.</a></li>
6373 </ul>
6374 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6375
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6376 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6377 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6378 defaults to using C calling conventions. The calling convention of the
6379 call must match the calling convention of the target function, or else the
6380 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6381
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6382 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6383 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6384 '<tt>inreg</tt>' attributes are valid here.</li>
6385
6386 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6387 type of the return value. Functions that return no value are marked
6388 <tt><a href="#t_void">void</a></tt>.</li>
6389
6390 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6391 being invoked. The argument types must match the types implied by this
6392 signature. This type can be omitted if the function is not varargs and if
6393 the function type does not return a pointer to a function.</li>
6394
6395 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6396 be invoked. In most cases, this is a direct function invocation, but
6397 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6398 to function value.</li>
6399
6400 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6401 signature argument types and parameter attributes. All arguments must be
6402 of <a href="#t_firstclass">first class</a> type. If the function
6403 signature indicates the function accepts a variable number of arguments,
6404 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6405
6406 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6407 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6408 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6409</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6410
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6411<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6412<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6413 a specified function, with its incoming arguments bound to the specified
6414 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6415 function, control flow continues with the instruction after the function
6416 call, and the return value of the function is bound to the result
6417 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6419<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6420<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6421 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6422 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6423 %X = tail call i32 @foo() <i>; yields i32</i>
6424 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6425 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6426
6427 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6428 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6429 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6430 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6431 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6432 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6433</pre>
6434
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6435<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6436standard C99 library as being the C99 library functions, and may perform
6437optimizations or generate code for them under that assumption. This is
6438something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6439freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6440
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6441</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6442
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6443<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6444<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6445 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6446</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6447
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6448<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6449
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6450<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6451<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6452 &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]6453</pre>
6454
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6455<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6456<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6457 the "variable argument" area of a function call. It is used to implement the
6458 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6459
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6460<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6461<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6462 argument. It returns a value of the specified argument type and increments
6463 the <tt>va_list</tt> to point to the next argument. The actual type
6464 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6465
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6466<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6467<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6468 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6469 to the next argument. For more information, see the variable argument
6470 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6471
6472<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]6473 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6474 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6475
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6476<p><tt>va_arg</tt> is an LLVM instruction instead of
6477 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6478 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6479
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6480<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6481<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6482
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6483<p>Note that the code generator does not yet fully support va_arg on many
6484 targets. Also, it does not currently support va_arg with aggregate types on
6485 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6486
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6487</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6488
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6489<!-- _______________________________________________________________________ -->
6490<h4>
6491 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6492</h4>
6493
6494<div>
6495
6496<h5>Syntax:</h5>
6497<pre>
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6498 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6499 &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]6500
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6501 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6502 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6503</pre>
6504
6505<h5>Overview:</h5>
6506<p>The '<tt>landingpad</tt>' instruction is used by
6507 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6508 system</a> to specify that a basic block is a landing pad &mdash; one where
6509 the exception lands, and corresponds to the code found in the
6510 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6511 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6512 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6513 type <tt>resultty</tt>.</p>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6514
6515<h5>Arguments:</h5>
6516<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6517 function associated with the unwinding mechanism. The optional
6518 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6519
6520<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6521 or <tt>filter</tt> &mdash; and contains the global variable representing the
6522 "type" that may be caught or filtered respectively. Unlike the
6523 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6524 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6525 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6526 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6527
6528<h5>Semantics:</h5>
6529<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6530 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6531 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6532 calling conventions, how the personality function results are represented in
6533 LLVM IR is target specific.</p>
6534
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6535<p>The clauses are applied in order from top to bottom. If two
6536 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6537 clauses from the calling function are appended to the list of clauses.
6538 When the call stack is being unwound due to an exception being thrown, the
6539 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6540 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6541 unwinding continues further up the call stack.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6542
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6543<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6544
6545<ul>
6546 <li>A landing pad block is a basic block which is the unwind destination of an
6547 '<tt>invoke</tt>' instruction.</li>
6548 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6549 first non-PHI instruction.</li>
6550 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6551 pad block.</li>
6552 <li>A basic block that is not a landing pad block may not include a
6553 '<tt>landingpad</tt>' instruction.</li>
6554 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6555 personality function.</li>
6556</ul>
6557
6558<h5>Example:</h5>
6559<pre>
6560 ;; A landing pad which can catch an integer.
6561 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6562 catch i8** @_ZTIi
6563 ;; A landing pad that is a cleanup.
6564 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6565 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6566 ;; A landing pad which can catch an integer and can only throw a double.
6567 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6568 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6569 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6570</pre>
6571
6572</div>
6573
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6574</div>
6575
6576</div>
6577
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6578<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6579<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6580<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6581
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6582<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6583
6584<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585 well known names and semantics and are required to follow certain
6586 restrictions. Overall, these intrinsics represent an extension mechanism for
6587 the LLVM language that does not require changing all of the transformations
6588 in LLVM when adding to the language (or the bitcode reader/writer, the
6589 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6590
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6591<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6592 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6593 begin with this prefix. Intrinsic functions must always be external
6594 functions: you cannot define the body of intrinsic functions. Intrinsic
6595 functions may only be used in call or invoke instructions: it is illegal to
6596 take the address of an intrinsic function. Additionally, because intrinsic
6597 functions are part of the LLVM language, it is required if any are added that
6598 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6599
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6600<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6601 family of functions that perform the same operation but on different data
6602 types. Because LLVM can represent over 8 million different integer types,
6603 overloading is used commonly to allow an intrinsic function to operate on any
6604 integer type. One or more of the argument types or the result type can be
6605 overloaded to accept any integer type. Argument types may also be defined as
6606 exactly matching a previous argument's type or the result type. This allows
6607 an intrinsic function which accepts multiple arguments, but needs all of them
6608 to be of the same type, to only be overloaded with respect to a single
6609 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6610
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6611<p>Overloaded intrinsics will have the names of its overloaded argument types
6612 encoded into its function name, each preceded by a period. Only those types
6613 which are overloaded result in a name suffix. Arguments whose type is matched
6614 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6615 can take an integer of any width and returns an integer of exactly the same
6616 integer width. This leads to a family of functions such as
6617 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6618 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6619 suffix is required. Because the argument's type is matched against the return
6620 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6621
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6622<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6623 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6624
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6625<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6626<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6627 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6628</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6629
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6630<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6631
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6632<p>Variable argument support is defined in LLVM with
6633 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6634 intrinsic functions. These functions are related to the similarly named
6635 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6636
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6637<p>All of these functions operate on arguments that use a target-specific value
6638 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6639 not define what this type is, so all transformations should be prepared to
6640 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6641
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6642<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]6643 instruction and the variable argument handling intrinsic functions are
6644 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6645
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6646<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6647define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6648 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6649 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6650 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6651 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6652
6653 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6654 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6655
6656 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6657 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6658 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6659 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6660 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6661
6662 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6663 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6664 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6665}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6666
6667declare void @llvm.va_start(i8*)
6668declare void @llvm.va_copy(i8*, i8*)
6669declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6670</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6671
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6672<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6673<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6674 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6675</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6676
6677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6678<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6679
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6680<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6681<pre>
6682 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6683</pre>
6684
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6686<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6687 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]6688
6689<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6690<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]6691
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6692<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6693<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]6694 macro available in C. In a target-dependent way, it initializes
6695 the <tt>va_list</tt> element to which the argument points, so that the next
6696 call to <tt>va_arg</tt> will produce the first variable argument passed to
6697 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6698 need to know the last argument of the function as the compiler can figure
6699 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6700
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6701</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6702
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6703<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6704<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6705 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6706</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6707
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6708<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6709
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6710<h5>Syntax:</h5>
6711<pre>
6712 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6713</pre>
6714
6715<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6716<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6717 which has been initialized previously
6718 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6719 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6720
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6721<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6722<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]6723
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6724<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6725<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]6726 macro available in C. In a target-dependent way, it destroys
6727 the <tt>va_list</tt> element to which the argument points. Calls
6728 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6729 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6730 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6731
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6732</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6733
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6734<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6735<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6736 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6737</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6738
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6739<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6740
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6741<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6742<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6743 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6744</pre>
6745
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6746<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6747<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6748 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6749
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6750<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6751<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]6752 The second argument is a pointer to a <tt>va_list</tt> element to copy
6753 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6754
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6755<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6756<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]6757 macro available in C. In a target-dependent way, it copies the
6758 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6759 element. This intrinsic is necessary because
6760 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6761 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6763</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6764
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6765</div>
6766
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6767<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6768<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6769 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6770</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6771
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6772<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6773
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6774<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6775Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6776intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6777roots on the stack</a>, as well as garbage collector implementations that
6778require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6779barriers. Front-ends for type-safe garbage collected languages should generate
6780these intrinsics to make use of the LLVM garbage collectors. For more details,
6781see <a href="GarbageCollection.html">Accurate Garbage Collection with
6782LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6783
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784<p>The garbage collection intrinsics only operate on objects in the generic
6785 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6786
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6787<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6788<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6789 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6790</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6791
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6792<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6793
6794<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6795<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6796 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6797</pre>
6798
6799<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6800<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]6801 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6802
6803<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6804<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6805 root pointer. The second pointer (which must be either a constant or a
6806 global value address) contains the meta-data to be associated with the
6807 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6808
6809<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6810<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]6811 location. At compile-time, the code generator generates information to allow
6812 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6813 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6814 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6815
6816</div>
6817
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6818<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6819<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6820 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6821</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6822
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6823<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6824
6825<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6826<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6827 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6828</pre>
6829
6830<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6831<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6832 locations, allowing garbage collector implementations that require read
6833 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6834
6835<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6836<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]6837 allocated from the garbage collector. The first object is a pointer to the
6838 start of the referenced object, if needed by the language runtime (otherwise
6839 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6840
6841<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6842<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6843 instruction, but may be replaced with substantially more complex code by the
6844 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6845 may only be used in a function which <a href="#gc">specifies a GC
6846 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6847
6848</div>
6849
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6850<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6851<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6852 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6853</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6854
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6855<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6856
6857<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6858<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6859 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6860</pre>
6861
6862<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6863<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6864 locations, allowing garbage collector implementations that require write
6865 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6866
6867<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6868<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]6869 object to store it to, and the third is the address of the field of Obj to
6870 store to. If the runtime does not require a pointer to the object, Obj may
6871 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6872
6873<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6874<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6875 instruction, but may be replaced with substantially more complex code by the
6876 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6877 may only be used in a function which <a href="#gc">specifies a GC
6878 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6879
6880</div>
6881
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6882</div>
6883
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6884<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6885<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6886 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6887</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6888
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6889<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6890
6891<p>These intrinsics are provided by LLVM to expose special features that may
6892 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6893
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6894<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6895<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6896 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6897</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6898
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6899<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6900
6901<h5>Syntax:</h5>
6902<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6903 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6904</pre>
6905
6906<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6908 target-specific value indicating the return address of the current function
6909 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6910
6911<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912<p>The argument to this intrinsic indicates which function to return the address
6913 for. Zero indicates the calling function, one indicates its caller, etc.
6914 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6915
6916<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6918 indicating the return address of the specified call frame, or zero if it
6919 cannot be identified. The value returned by this intrinsic is likely to be
6920 incorrect or 0 for arguments other than zero, so it should only be used for
6921 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6922
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6923<p>Note that calling this intrinsic does not prevent function inlining or other
6924 aggressive transformations, so the value returned may not be that of the
6925 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6926
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6927</div>
6928
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6929<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6930<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6931 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6932</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6933
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6934<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6935
6936<h5>Syntax:</h5>
6937<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6938 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6939</pre>
6940
6941<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6942<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6943 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6944
6945<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946<p>The argument to this intrinsic indicates which function to return the frame
6947 pointer for. Zero indicates the calling function, one indicates its caller,
6948 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6949
6950<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6951<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6952 indicating the frame address of the specified call frame, or zero if it
6953 cannot be identified. The value returned by this intrinsic is likely to be
6954 incorrect or 0 for arguments other than zero, so it should only be used for
6955 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6956
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6957<p>Note that calling this intrinsic does not prevent function inlining or other
6958 aggressive transformations, so the value returned may not be that of the
6959 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6960
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6961</div>
6962
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6963<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6964<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6965 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6966</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6967
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6968<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6969
6970<h5>Syntax:</h5>
6971<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6972 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6973</pre>
6974
6975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6976<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6977 of the function stack, for use
6978 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6979 useful for implementing language features like scoped automatic variable
6980 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6981
6982<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p>This intrinsic returns a opaque pointer value that can be passed
6984 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6985 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6986 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6987 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6988 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6989 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6990
6991</div>
6992
6993<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6994<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6995 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6996</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6997
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6998<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6999
7000<h5>Syntax:</h5>
7001<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7002 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]7003</pre>
7004
7005<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7006<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
7007 the function stack to the state it was in when the
7008 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
7009 executed. This is useful for implementing language features like scoped
7010 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]7011
7012<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7013<p>See the description
7014 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]7015
7016</div>
7017
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]7018<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7019<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7020 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7021</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]7022
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7023<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]7024
7025<h5>Syntax:</h5>
7026<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]7027 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]7028</pre>
7029
7030<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7031<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
7032 insert a prefetch instruction if supported; otherwise, it is a noop.
7033 Prefetches have no effect on the behavior of the program but can change its
7034 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]7035
7036<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7037<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
7038 specifier determining if the fetch should be for a read (0) or write (1),
7039 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]7040 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
7041 specifies whether the prefetch is performed on the data (1) or instruction (0)
7042 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
7043 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]7044
7045<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7046<p>This intrinsic does not modify the behavior of the program. In particular,
7047 prefetches cannot trap and do not produce a value. On targets that support
7048 this intrinsic, the prefetch can provide hints to the processor cache for
7049 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]7050
7051</div>
7052
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7053<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7054<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7055 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7056</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7057
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7058<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7059
7060<h5>Syntax:</h5>
7061<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]7062 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7063</pre>
7064
7065<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7066<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
7067 Counter (PC) in a region of code to simulators and other tools. The method
7068 is target specific, but it is expected that the marker will use exported
7069 symbols to transmit the PC of the marker. The marker makes no guarantees
7070 that it will remain with any specific instruction after optimizations. It is
7071 possible that the presence of a marker will inhibit optimizations. The
7072 intended use is to be inserted after optimizations to allow correlations of
7073 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7074
7075<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7076<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7077
7078<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7079<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7080 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]7081
7082</div>
7083
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7084<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7085<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7086 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7087</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7088
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7089<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7090
7091<h5>Syntax:</h5>
7092<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7093 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7094</pre>
7095
7096<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
7098 counter register (or similar low latency, high accuracy clocks) on those
7099 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7100 should map to RPCC. As the backing counters overflow quickly (on the order
7101 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7102
7103<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7104<p>When directly supported, reading the cycle counter should not modify any
7105 memory. Implementations are allowed to either return a application specific
7106 value or a system wide value. On backends without support, this is lowered
7107 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7108
7109</div>
7110
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7111</div>
7112
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7113<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7114<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7115 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7116</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7117
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7118<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119
7120<p>LLVM provides intrinsics for a few important standard C library functions.
7121 These intrinsics allow source-language front-ends to pass information about
7122 the alignment of the pointer arguments to the code generator, providing
7123 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7124
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7125<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7126<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7127 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7128</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7129
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7130<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7131
7132<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7133<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]7134 integer bit width and for different address spaces. Not all targets support
7135 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7136
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7137<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7138 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]7139 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7140 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]7141 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7142</pre>
7143
7144<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7145<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7146 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7147
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7148<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7149 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7150 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7151
7152<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7153
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7154<p>The first argument is a pointer to the destination, the second is a pointer
7155 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7156 number of bytes to copy, the fourth argument is the alignment of the
7157 source and destination locations, and the fifth is a boolean indicating a
7158 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7159
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7160<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]7161 then the caller guarantees that both the source and destination pointers are
7162 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7163
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7164<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7165 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7166 The detailed access behavior is not very cleanly specified and it is unwise
7167 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7168
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7169<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7170
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7171<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7172 source location to the destination location, which are not allowed to
7173 overlap. It copies "len" bytes of memory over. If the argument is known to
7174 be aligned to some boundary, this can be specified as the fourth argument,
7175 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7176
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7177</div>
7178
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7179<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7180<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7181 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7182</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7183
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7184<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7185
7186<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7187<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]7188 width and for different address space. Not all targets support all bit
7189 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7191<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7192 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]7193 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7194 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]7195 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7196</pre>
7197
7198<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7199<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7200 source location to the destination location. It is similar to the
7201 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7202 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7203
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7204<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7205 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7206 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7207
7208<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7209
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210<p>The first argument is a pointer to the destination, the second is a pointer
7211 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7212 number of bytes to copy, the fourth argument is the alignment of the
7213 source and destination locations, and the fifth is a boolean indicating a
7214 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +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 source and destination pointers are
7218 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +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.memmove</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 Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7225<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7226
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7228 source location to the destination location, which may overlap. It copies
7229 "len" bytes of memory over. If the argument is known to be aligned to some
7230 boundary, this can be specified as the fourth argument, otherwise it should
7231 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7232
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7233</div>
7234
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7235<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7236<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7237 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7238</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7239
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7240<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7241
7242<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7243<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]7244 width and for different address spaces. However, not all targets support all
7245 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7246
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7247<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7248 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7249 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7250 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7251 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7252</pre>
7253
7254<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7256 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7257
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7258<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7259 intrinsic does not return a value and takes extra alignment/volatile
7260 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7261
7262<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7263<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]7264 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7265 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7266 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7267
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7268<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]7269 then the caller guarantees that the destination pointer is aligned to that
7270 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7271
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7272<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7273 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7274 The detailed access behavior is not very cleanly specified and it is unwise
7275 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7276
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7277<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7278<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7279 at the destination location. If the argument is known to be aligned to some
7280 boundary, this can be specified as the fourth argument, otherwise it should
7281 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7282
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7283</div>
7284
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7285<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7286<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7287 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7288</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7289
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7290<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7291
7292<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7293<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7294 floating point or vector of floating point type. Not all targets support all
7295 types however.</p>
7296
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7297<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7298 declare float @llvm.sqrt.f32(float %Val)
7299 declare double @llvm.sqrt.f64(double %Val)
7300 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7301 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7302 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7303</pre>
7304
7305<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7306<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7307 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7308 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7309 behavior for negative numbers other than -0.0 (which allows for better
7310 optimization, because there is no need to worry about errno being
7311 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]7312
7313<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7314<p>The argument and return value are floating point numbers of the same
7315 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7316
7317<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7318<p>This function returns the sqrt of the specified operand if it is a
7319 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7320
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7321</div>
7322
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7323<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7324<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7325 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7326</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7327
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7328<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7329
7330<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7331<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7332 floating point or vector of floating point type. Not all targets support all
7333 types however.</p>
7334
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7335<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7336 declare float @llvm.powi.f32(float %Val, i32 %power)
7337 declare double @llvm.powi.f64(double %Val, i32 %power)
7338 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7339 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7340 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7341</pre>
7342
7343<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7344<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7345 specified (positive or negative) power. The order of evaluation of
7346 multiplications is not defined. When a vector of floating point type is
7347 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7348
7349<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7350<p>The second argument is an integer power, and the first is a value to raise to
7351 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7352
7353<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7354<p>This function returns the first value raised to the second power with an
7355 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7356
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7357</div>
7358
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7359<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7360<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7361 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7362</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7363
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7364<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7365
7366<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7367<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7368 floating point or vector of floating point type. Not all targets support all
7369 types however.</p>
7370
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7371<pre>
7372 declare float @llvm.sin.f32(float %Val)
7373 declare double @llvm.sin.f64(double %Val)
7374 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7375 declare fp128 @llvm.sin.f128(fp128 %Val)
7376 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7377</pre>
7378
7379<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7380<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7381
7382<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7383<p>The argument and return value are floating point numbers of the same
7384 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7385
7386<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7387<p>This function returns the sine of the specified operand, returning the same
7388 values as the libm <tt>sin</tt> functions would, and handles error conditions
7389 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7390
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7391</div>
7392
7393<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7394<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7395 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7396</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7397
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7398<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7399
7400<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7401<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7402 floating point or vector of floating point type. Not all targets support all
7403 types however.</p>
7404
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7405<pre>
7406 declare float @llvm.cos.f32(float %Val)
7407 declare double @llvm.cos.f64(double %Val)
7408 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7409 declare fp128 @llvm.cos.f128(fp128 %Val)
7410 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7411</pre>
7412
7413<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7414<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7415
7416<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7417<p>The argument and return value are floating point numbers of the same
7418 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7419
7420<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7421<p>This function returns the cosine of the specified operand, returning the same
7422 values as the libm <tt>cos</tt> functions would, and handles error conditions
7423 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7424
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7425</div>
7426
7427<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7428<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7429 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7430</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7431
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7432<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7433
7434<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7435<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7436 floating point or vector of floating point type. Not all targets support all
7437 types however.</p>
7438
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7439<pre>
7440 declare float @llvm.pow.f32(float %Val, float %Power)
7441 declare double @llvm.pow.f64(double %Val, double %Power)
7442 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7443 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7444 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7445</pre>
7446
7447<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7448<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7449 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7450
7451<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7452<p>The second argument is a floating point power, and the first is a value to
7453 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7454
7455<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7456<p>This function returns the first value raised to the second power, returning
7457 the same values as the libm <tt>pow</tt> functions would, and handles error
7458 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7459
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7460</div>
7461
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7462<!-- _______________________________________________________________________ -->
7463<h4>
7464 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7465</h4>
7466
7467<div>
7468
7469<h5>Syntax:</h5>
7470<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7471 floating point or vector of floating point type. Not all targets support all
7472 types however.</p>
7473
7474<pre>
7475 declare float @llvm.exp.f32(float %Val)
7476 declare double @llvm.exp.f64(double %Val)
7477 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7478 declare fp128 @llvm.exp.f128(fp128 %Val)
7479 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7480</pre>
7481
7482<h5>Overview:</h5>
7483<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7484
7485<h5>Arguments:</h5>
7486<p>The argument and return value are floating point numbers of the same
7487 type.</p>
7488
7489<h5>Semantics:</h5>
7490<p>This function returns the same values as the libm <tt>exp</tt> functions
7491 would, and handles error conditions in the same way.</p>
7492
7493</div>
7494
7495<!-- _______________________________________________________________________ -->
7496<h4>
7497 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7498</h4>
7499
7500<div>
7501
7502<h5>Syntax:</h5>
7503<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7504 floating point or vector of floating point type. Not all targets support all
7505 types however.</p>
7506
7507<pre>
7508 declare float @llvm.log.f32(float %Val)
7509 declare double @llvm.log.f64(double %Val)
7510 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7511 declare fp128 @llvm.log.f128(fp128 %Val)
7512 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7513</pre>
7514
7515<h5>Overview:</h5>
7516<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7517
7518<h5>Arguments:</h5>
7519<p>The argument and return value are floating point numbers of the same
7520 type.</p>
7521
7522<h5>Semantics:</h5>
7523<p>This function returns the same values as the libm <tt>log</tt> functions
7524 would, and handles error conditions in the same way.</p>
7525
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7526</div>
7527
7528<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7529<h4>
7530 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7531</h4>
7532
7533<div>
7534
7535<h5>Syntax:</h5>
7536<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7537 floating point or vector of floating point type. Not all targets support all
7538 types however.</p>
7539
7540<pre>
7541 declare float @llvm.fma.f32(float %a, float %b, float %c)
7542 declare double @llvm.fma.f64(double %a, double %b, double %c)
7543 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7544 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7545 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7546</pre>
7547
7548<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7549<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7550 operation.</p>
7551
7552<h5>Arguments:</h5>
7553<p>The argument and return value are floating point numbers of the same
7554 type.</p>
7555
7556<h5>Semantics:</h5>
7557<p>This function returns the same values as the libm <tt>fma</tt> functions
7558 would.</p>
7559
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7560</div>
7561
Peter Collingbourne168a4c32012-07-03 12:25:40 +0000[diff] [blame]7562<!-- _______________________________________________________________________ -->
7563<h4>
7564 <a name="int_fabs">'<tt>llvm.fabs.*</tt>' Intrinsic</a>
7565</h4>
7566
7567<div>
7568
7569<h5>Syntax:</h5>
7570<p>This is an overloaded intrinsic. You can use <tt>llvm.fabs</tt> on any
7571 floating point or vector of floating point type. Not all targets support all
7572 types however.</p>
7573
7574<pre>
7575 declare float @llvm.fabs.f32(float %Val)
7576 declare double @llvm.fabs.f64(double %Val)
7577 declare x86_fp80 @llvm.fabs.f80(x86_fp80 %Val)
7578 declare fp128 @llvm.fabs.f128(fp128 %Val)
7579 declare ppc_fp128 @llvm.fabs.ppcf128(ppc_fp128 %Val)
7580</pre>
7581
7582<h5>Overview:</h5>
7583<p>The '<tt>llvm.fabs.*</tt>' intrinsics return the absolute value of
7584 the operand.</p>
7585
7586<h5>Arguments:</h5>
7587<p>The argument and return value are floating point numbers of the same
7588 type.</p>
7589
7590<h5>Semantics:</h5>
7591<p>This function returns the same values as the libm <tt>fabs</tt> functions
7592 would, and handles error conditions in the same way.</p>
7593
7594</div>
7595
Dan Gohman27db99f2012-07-26 17:43:27 +0000[diff] [blame]7596<!-- _______________________________________________________________________ -->
7597<h4>
7598 <a name="int_floor">'<tt>llvm.floor.*</tt>' Intrinsic</a>
7599</h4>
7600
7601<div>
7602
7603<h5>Syntax:</h5>
7604<p>This is an overloaded intrinsic. You can use <tt>llvm.floor</tt> on any
7605 floating point or vector of floating point type. Not all targets support all
7606 types however.</p>
7607
7608<pre>
7609 declare float @llvm.floor.f32(float %Val)
7610 declare double @llvm.floor.f64(double %Val)
7611 declare x86_fp80 @llvm.floor.f80(x86_fp80 %Val)
7612 declare fp128 @llvm.floor.f128(fp128 %Val)
7613 declare ppc_fp128 @llvm.floor.ppcf128(ppc_fp128 %Val)
7614</pre>
7615
7616<h5>Overview:</h5>
7617<p>The '<tt>llvm.floor.*</tt>' intrinsics return the floor of
7618 the operand.</p>
7619
7620<h5>Arguments:</h5>
7621<p>The argument and return value are floating point numbers of the same
7622 type.</p>
7623
7624<h5>Semantics:</h5>
7625<p>This function returns the same values as the libm <tt>floor</tt> functions
7626 would, and handles error conditions in the same way.</p>
7627
7628</div>
7629
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7630</div>
7631
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7632<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7633<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7634 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7635</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7636
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7637<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7638
7639<p>LLVM provides intrinsics for a few important bit manipulation operations.
7640 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7641
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7642<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7643<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7644 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7645</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7646
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7647<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7648
7649<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7650<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7651 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7652
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7653<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7654 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7655 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7656 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7657</pre>
7658
7659<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7660<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7661 values with an even number of bytes (positive multiple of 16 bits). These
7662 are useful for performing operations on data that is not in the target's
7663 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7664
7665<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7666<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7667 and low byte of the input i16 swapped. Similarly,
7668 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7669 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7670 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7671 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7672 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7673 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7674
7675</div>
7676
7677<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7678<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7679 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7680</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7681
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7682<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7683
7684<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7685<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]7686 width, or on any vector with integer elements. Not all targets support all
7687 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7688
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7689<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7690 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7691 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7692 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7693 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7694 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7695 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]7696</pre>
7697
7698<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7699<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7700 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7701
7702<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7703<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]7704 integer type, or a vector with integer elements.
7705 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7706
7707<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7708<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7709 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7710
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7711</div>
7712
7713<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7714<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7715 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7716</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7718<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7719
7720<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7721<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]7722 integer bit width, or any vector whose elements are integers. Not all
7723 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7724
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7725<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7726 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7727 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7728 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7729 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7730 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7731 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]7732</pre>
7733
7734<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7735<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7736 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7737
7738<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7739<p>The first argument is the value to be counted. This argument may be of any
7740 integer type, or a vectory with integer element type. The return type
7741 must match the first argument type.</p>
7742
7743<p>The second argument must be a constant and is a flag to indicate whether the
7744 intrinsic should ensure that a zero as the first argument produces a defined
7745 result. Historically some architectures did not provide a defined result for
7746 zero values as efficiently, and many algorithms are now predicated on
7747 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7748
7749<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7750<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7751 zeros in a variable, or within each element of the vector.
7752 If <tt>src == 0</tt> then the result is the size in bits of the type of
7753 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7754 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7755
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7756</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7757
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7758<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7759<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7760 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7761</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7762
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7763<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7764
7765<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7766<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]7767 integer bit width, or any vector of integer elements. Not all targets
7768 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7769
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7770<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7771 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7772 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7773 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7774 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7775 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7776 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]7777</pre>
7778
7779<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7780<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7781 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7782
7783<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7784<p>The first argument is the value to be counted. This argument may be of any
7785 integer type, or a vectory with integer element type. The return type
7786 must match the first argument type.</p>
7787
7788<p>The second argument must be a constant and is a flag to indicate whether the
7789 intrinsic should ensure that a zero as the first argument produces a defined
7790 result. Historically some architectures did not provide a defined result for
7791 zero values as efficiently, and many algorithms are now predicated on
7792 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7793
7794<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7795<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7796 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7797 If <tt>src == 0</tt> then the result is the size in bits of the type of
7798 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7799 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7800
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7801</div>
7802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7803</div>
7804
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7805<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7806<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7807 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7808</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7809
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7810<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7811
7812<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7813
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7814<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7815<h4>
7816 <a name="int_sadd_overflow">
7817 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7818 </a>
7819</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7820
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7821<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7822
7823<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7824<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]7825 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7826
7827<pre>
7828 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7829 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7830 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7831</pre>
7832
7833<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7834<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7835 a signed addition of the two arguments, and indicate whether an overflow
7836 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7837
7838<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7839<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]7840 be of integer types of any bit width, but they must have the same bit
7841 width. The second element of the result structure must be of
7842 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7843 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7844
7845<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7846<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7847 a signed addition of the two variables. They return a structure &mdash; the
7848 first element of which is the signed summation, and the second element of
7849 which is a bit specifying if the signed summation resulted in an
7850 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7851
7852<h5>Examples:</h5>
7853<pre>
7854 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7855 %sum = extractvalue {i32, i1} %res, 0
7856 %obit = extractvalue {i32, i1} %res, 1
7857 br i1 %obit, label %overflow, label %normal
7858</pre>
7859
7860</div>
7861
7862<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7863<h4>
7864 <a name="int_uadd_overflow">
7865 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7866 </a>
7867</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7868
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7869<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7870
7871<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7872<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]7873 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7874
7875<pre>
7876 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7877 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7878 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7879</pre>
7880
7881<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7882<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7883 an unsigned addition of the two arguments, and indicate whether a carry
7884 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7885
7886<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7887<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]7888 be of integer types of any bit width, but they must have the same bit
7889 width. The second element of the result structure must be of
7890 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7891 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7892
7893<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7894<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7895 an unsigned addition of the two arguments. They return a structure &mdash;
7896 the first element of which is the sum, and the second element of which is a
7897 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7898
7899<h5>Examples:</h5>
7900<pre>
7901 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7902 %sum = extractvalue {i32, i1} %res, 0
7903 %obit = extractvalue {i32, i1} %res, 1
7904 br i1 %obit, label %carry, label %normal
7905</pre>
7906
7907</div>
7908
7909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7910<h4>
7911 <a name="int_ssub_overflow">
7912 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7913 </a>
7914</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7915
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7916<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7917
7918<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7919<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]7920 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7921
7922<pre>
7923 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7924 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7925 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7926</pre>
7927
7928<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7929<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7930 a signed subtraction of the two arguments, and indicate whether an overflow
7931 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7932
7933<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7934<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]7935 be of integer types of any bit width, but they must have the same bit
7936 width. The second element of the result structure must be of
7937 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7938 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7939
7940<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7941<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7942 a signed subtraction of the two arguments. They return a structure &mdash;
7943 the first element of which is the subtraction, and the second element of
7944 which is a bit specifying if the signed subtraction resulted in an
7945 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7946
7947<h5>Examples:</h5>
7948<pre>
7949 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7950 %sum = extractvalue {i32, i1} %res, 0
7951 %obit = extractvalue {i32, i1} %res, 1
7952 br i1 %obit, label %overflow, label %normal
7953</pre>
7954
7955</div>
7956
7957<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7958<h4>
7959 <a name="int_usub_overflow">
7960 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7961 </a>
7962</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7963
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7964<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7965
7966<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7967<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]7968 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7969
7970<pre>
7971 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7972 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7973 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7974</pre>
7975
7976<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7977<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7978 an unsigned subtraction of the two arguments, and indicate whether an
7979 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7980
7981<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7982<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]7983 be of integer types of any bit width, but they must have the same bit
7984 width. The second element of the result structure must be of
7985 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7986 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7987
7988<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7989<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7990 an unsigned subtraction of the two arguments. They return a structure &mdash;
7991 the first element of which is the subtraction, and the second element of
7992 which is a bit specifying if the unsigned subtraction resulted in an
7993 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7994
7995<h5>Examples:</h5>
7996<pre>
7997 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7998 %sum = extractvalue {i32, i1} %res, 0
7999 %obit = extractvalue {i32, i1} %res, 1
8000 br i1 %obit, label %overflow, label %normal
8001</pre>
8002
8003</div>
8004
8005<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8006<h4>
8007 <a name="int_smul_overflow">
8008 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
8009 </a>
8010</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8011
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8012<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8013
8014<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8015<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]8016 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8017
8018<pre>
8019 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
8020 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
8021 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
8022</pre>
8023
8024<h5>Overview:</h5>
8025
8026<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8027 a signed multiplication of the two arguments, and indicate whether an
8028 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8029
8030<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8031<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]8032 be of integer types of any bit width, but they must have the same bit
8033 width. The second element of the result structure must be of
8034 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
8035 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8036
8037<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8038<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8039 a signed multiplication of the two arguments. They return a structure &mdash;
8040 the first element of which is the multiplication, and the second element of
8041 which is a bit specifying if the signed multiplication resulted in an
8042 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]8043
8044<h5>Examples:</h5>
8045<pre>
8046 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
8047 %sum = extractvalue {i32, i1} %res, 0
8048 %obit = extractvalue {i32, i1} %res, 1
8049 br i1 %obit, label %overflow, label %normal
8050</pre>
8051
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]8052</div>
8053
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8054<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8055<h4>
8056 <a name="int_umul_overflow">
8057 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
8058 </a>
8059</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8060
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8061<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8062
8063<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8064<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]8065 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8066
8067<pre>
8068 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
8069 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
8070 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
8071</pre>
8072
8073<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8074<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8075 a unsigned multiplication of the two arguments, and indicate whether an
8076 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8077
8078<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8079<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]8080 be of integer types of any bit width, but they must have the same bit
8081 width. The second element of the result structure must be of
8082 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
8083 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8084
8085<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8086<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8087 an unsigned multiplication of the two arguments. They return a structure
8088 &mdash; the first element of which is the multiplication, and the second
8089 element of which is a bit specifying if the unsigned multiplication resulted
8090 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]8091
8092<h5>Examples:</h5>
8093<pre>
8094 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
8095 %sum = extractvalue {i32, i1} %res, 0
8096 %obit = extractvalue {i32, i1} %res, 1
8097 br i1 %obit, label %overflow, label %normal
8098</pre>
8099
8100</div>
8101
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8102</div>
8103
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8104<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8105<h3>
Lang Hames5afba6f2012-06-05 19:07:46 +0000[diff] [blame]8106 <a name="spec_arithmetic">Specialised Arithmetic Intrinsics</a>
8107</h3>
8108
8109<!-- _______________________________________________________________________ -->
8110
8111<h4>
8112 <a name="fmuladd">'<tt>llvm.fmuladd.*</tt>' Intrinsic</a>
8113</h4>
8114
8115<div>
8116
8117<h5>Syntax:</h5>
8118<pre>
8119 declare float @llvm.fmuladd.f32(float %a, float %b, float %c)
8120 declare double @llvm.fmuladd.f64(double %a, double %b, double %c)
8121</pre>
8122
8123<h5>Overview:</h5>
8124<p>The '<tt>llvm.fmuladd.*</tt>' intrinsic functions represent multiply-add
8125expressions that can be fused if the code generator determines that the fused
8126expression would be legal and efficient.</p>
8127
8128<h5>Arguments:</h5>
8129<p>The '<tt>llvm.fmuladd.*</tt>' intrinsics each take three arguments: two
8130multiplicands, a and b, and an addend c.</p>
8131
8132<h5>Semantics:</h5>
8133<p>The expression:</p>
8134<pre>
8135 %0 = call float @llvm.fmuladd.f32(%a, %b, %c)
8136</pre>
8137<p>is equivalent to the expression a * b + c, except that rounding will not be
8138performed between the multiplication and addition steps if the code generator
8139fuses the operations. Fusion is not guaranteed, even if the target platform
8140supports it. If a fused multiply-add is required the corresponding llvm.fma.*
8141intrinsic function should be used instead.</p>
8142
8143<h5>Examples:</h5>
8144<pre>
8145 %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields {float}:r2 = (a * b) + c
8146</pre>
8147
8148</div>
8149
8150<!-- ======================================================================= -->
8151<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8152 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8153</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8154
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8155<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8156
Tobias Grosser057beb82012-05-24 15:59:06 +0000[diff] [blame]8157<p>For most target platforms, half precision floating point is a storage-only
8158 format. This means that it is
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8159 a dense encoding (in memory) but does not support computation in the
8160 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8161
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8162<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8163 value as an i16, then convert it to float with <a
8164 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
8165 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8166 double etc). To store the value back to memory, it is first converted to
8167 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8168 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
8169 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8170
8171<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8172<h4>
8173 <a name="int_convert_to_fp16">
8174 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
8175 </a>
8176</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8177
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8178<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8179
8180<h5>Syntax:</h5>
8181<pre>
8182 declare i16 @llvm.convert.to.fp16(f32 %a)
8183</pre>
8184
8185<h5>Overview:</h5>
8186<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8187 a conversion from single precision floating point format to half precision
8188 floating point format.</p>
8189
8190<h5>Arguments:</h5>
8191<p>The intrinsic function contains single argument - the value to be
8192 converted.</p>
8193
8194<h5>Semantics:</h5>
8195<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
8196 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8197 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8198 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8199
8200<h5>Examples:</h5>
8201<pre>
8202 %res = call i16 @llvm.convert.to.fp16(f32 %a)
8203 store i16 %res, i16* @x, align 2
8204</pre>
8205
8206</div>
8207
8208<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8209<h4>
8210 <a name="int_convert_from_fp16">
8211 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8212 </a>
8213</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8214
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8215<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8216
8217<h5>Syntax:</h5>
8218<pre>
8219 declare f32 @llvm.convert.from.fp16(i16 %a)
8220</pre>
8221
8222<h5>Overview:</h5>
8223<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8224 a conversion from half precision floating point format to single precision
8225 floating point format.</p>
8226
8227<h5>Arguments:</h5>
8228<p>The intrinsic function contains single argument - the value to be
8229 converted.</p>
8230
8231<h5>Semantics:</h5>
8232<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8233 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8234 precision floating point format. The input half-float value is represented by
8235 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8236
8237<h5>Examples:</h5>
8238<pre>
8239 %a = load i16* @x, align 2
8240 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8241</pre>
8242
8243</div>
8244
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8245</div>
8246
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8247<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8248<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8249 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8250</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8251
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8252<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8253
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8254<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8255 prefix), are described in
8256 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8257 Level Debugging</a> document.</p>
8258
8259</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8260
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8261<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8262<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8263 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8264</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8265
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8266<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8267
8268<p>The LLVM exception handling intrinsics (which all start with
8269 <tt>llvm.eh.</tt> prefix), are described in
8270 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8271 Handling</a> document.</p>
8272
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8273</div>
8274
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8275<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8276<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8277 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8278</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8280<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8281
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8282<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]8283 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8284 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8285 function pointer lacking the nest parameter - the caller does not need to
8286 provide a value for it. Instead, the value to use is stored in advance in a
8287 "trampoline", a block of memory usually allocated on the stack, which also
8288 contains code to splice the nest value into the argument list. This is used
8289 to implement the GCC nested function address extension.</p>
8290
8291<p>For example, if the function is
8292 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8293 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8294 follows:</p>
8295
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]8296<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8297 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8298 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8299 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8300 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8301 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8302</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8303
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8304<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8305 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8306
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8307<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8308<h4>
8309 <a name="int_it">
8310 '<tt>llvm.init.trampoline</tt>' Intrinsic
8311 </a>
8312</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8313
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8314<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8315
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8316<h5>Syntax:</h5>
8317<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8318 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]8319</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8320
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8321<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8322<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8323 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8324
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8325<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8326<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8327 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8328 sufficiently aligned block of memory; this memory is written to by the
8329 intrinsic. Note that the size and the alignment are target-specific - LLVM
8330 currently provides no portable way of determining them, so a front-end that
8331 generates this intrinsic needs to have some target-specific knowledge.
8332 The <tt>func</tt> argument must hold a function bitcast to
8333 an <tt>i8*</tt>.</p>
8334
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8335<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8336<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]8337 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8338 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8339 which can be <a href="#int_trampoline">bitcast (to a new function) and
8340 called</a>. The new function's signature is the same as that of
8341 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8342 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8343 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8344 with the same argument list, but with <tt>nval</tt> used for the missing
8345 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8346 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8347 to the returned function pointer is undefined.</p>
8348</div>
8349
8350<!-- _______________________________________________________________________ -->
8351<h4>
8352 <a name="int_at">
8353 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8354 </a>
8355</h4>
8356
8357<div>
8358
8359<h5>Syntax:</h5>
8360<pre>
8361 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8362</pre>
8363
8364<h5>Overview:</h5>
8365<p>This performs any required machine-specific adjustment to the address of a
8366 trampoline (passed as <tt>tramp</tt>).</p>
8367
8368<h5>Arguments:</h5>
8369<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8370 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8371 </a>.</p>
8372
8373<h5>Semantics:</h5>
8374<p>On some architectures the address of the code to be executed needs to be
8375 different to the address where the trampoline is actually stored. This
8376 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8377 after performing the required machine specific adjustments.
8378 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8379 executed</a>.
8380</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8381
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8382</div>
8383
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8384</div>
8385
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8386<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8387<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8388 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8389</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8390
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8391<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8392
8393<p>This class of intrinsics exists to information about the lifetime of memory
8394 objects and ranges where variables are immutable.</p>
8395
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8396<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8397<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8398 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8399</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8400
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8401<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8402
8403<h5>Syntax:</h5>
8404<pre>
8405 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8406</pre>
8407
8408<h5>Overview:</h5>
8409<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8410 object's lifetime.</p>
8411
8412<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8413<p>The first argument is a constant integer representing the size of the
8414 object, or -1 if it is variable sized. The second argument is a pointer to
8415 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8416
8417<h5>Semantics:</h5>
8418<p>This intrinsic indicates that before this point in the code, the value of the
8419 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]8420 never be used and has an undefined value. A load from the pointer that
8421 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8422 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8423
8424</div>
8425
8426<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8427<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8428 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8429</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8430
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8431<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8432
8433<h5>Syntax:</h5>
8434<pre>
8435 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8436</pre>
8437
8438<h5>Overview:</h5>
8439<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8440 object's lifetime.</p>
8441
8442<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8443<p>The first argument is a constant integer representing the size of the
8444 object, or -1 if it is variable sized. The second argument is a pointer to
8445 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8446
8447<h5>Semantics:</h5>
8448<p>This intrinsic indicates that after this point in the code, the value of the
8449 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8450 never be used and has an undefined value. Any stores into the memory object
8451 following this intrinsic may be removed as dead.
8452
8453</div>
8454
8455<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8456<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8457 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8458</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8459
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8460<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8461
8462<h5>Syntax:</h5>
8463<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8464 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8465</pre>
8466
8467<h5>Overview:</h5>
8468<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8469 a memory object will not change.</p>
8470
8471<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8472<p>The first argument is a constant integer representing the size of the
8473 object, or -1 if it is variable sized. The second argument is a pointer to
8474 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8475
8476<h5>Semantics:</h5>
8477<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8478 the return value, the referenced memory location is constant and
8479 unchanging.</p>
8480
8481</div>
8482
8483<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8484<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8485 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8486</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8487
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8488<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8489
8490<h5>Syntax:</h5>
8491<pre>
8492 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8493</pre>
8494
8495<h5>Overview:</h5>
8496<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8497 a memory object are mutable.</p>
8498
8499<h5>Arguments:</h5>
8500<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8501 The second argument is a constant integer representing the size of the
8502 object, or -1 if it is variable sized and the third argument is a pointer
8503 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8504
8505<h5>Semantics:</h5>
8506<p>This intrinsic indicates that the memory is mutable again.</p>
8507
8508</div>
8509
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8510</div>
8511
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8512<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8513<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8514 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8515</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8516
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8517<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8518
8519<p>This class of intrinsics is designed to be generic and has no specific
8520 purpose.</p>
8521
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8522<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8523<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8524 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8525</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8526
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8527<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8528
8529<h5>Syntax:</h5>
8530<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8531 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]8532</pre>
8533
8534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8535<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8536
8537<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8538<p>The first argument is a pointer to a value, the second is a pointer to a
8539 global string, the third is a pointer to a global string which is the source
8540 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8541
8542<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8543<p>This intrinsic allows annotation of local variables with arbitrary strings.
8544 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8545 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8546 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8547
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8548</div>
8549
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8550<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8551<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8552 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8553</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8554
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8555<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8556
8557<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8558<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8559 any integer bit width.</p>
8560
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8561<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8562 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8563 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8564 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8565 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8566 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]8567</pre>
8568
8569<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8570<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8571
8572<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8573<p>The first argument is an integer value (result of some expression), the
8574 second is a pointer to a global string, the third is a pointer to a global
8575 string which is the source file name, and the last argument is the line
8576 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8577
8578<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8579<p>This intrinsic allows annotations to be put on arbitrary expressions with
8580 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8581 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8582 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8583
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8584</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8585
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8586<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8587<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8588 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8589</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8590
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8591<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8592
8593<h5>Syntax:</h5>
8594<pre>
Chris Lattner86208902012-05-27 23:20:41 +0000[diff] [blame]8595 declare void @llvm.trap() noreturn nounwind
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8596</pre>
8597
8598<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8599<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8600
8601<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8602<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8603
8604<h5>Semantics:</h5>
John Criswell99534f32012-05-16 00:26:51 +0000[diff] [blame]8605<p>This intrinsic is lowered to the target dependent trap instruction. If the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8606 target does not have a trap instruction, this intrinsic will be lowered to
John Criswell99534f32012-05-16 00:26:51 +0000[diff] [blame]8607 a call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8608
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8609</div>
8610
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8611<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8612<h4>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]8613 <a name="int_debugtrap">'<tt>llvm.debugtrap</tt>' Intrinsic</a>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8614</h4>
8615
8616<div>
8617
8618<h5>Syntax:</h5>
8619<pre>
Chris Lattner86208902012-05-27 23:20:41 +0000[diff] [blame]8620 declare void @llvm.debugtrap() nounwind
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8621</pre>
8622
8623<h5>Overview:</h5>
Dan Gohmana6063c62012-05-14 18:58:10 +0000[diff] [blame]8624<p>The '<tt>llvm.debugtrap</tt>' intrinsic.</p>
Dan Gohmand4347e12012-05-11 00:19:32 +0000[diff] [blame]8625
8626<h5>Arguments:</h5>
8627<p>None.</p>
8628
8629<h5>Semantics:</h5>
8630<p>This intrinsic is lowered to code which is intended to cause an execution
8631 trap with the intention of requesting the attention of a debugger.</p>
8632
8633</div>
8634
8635<!-- _______________________________________________________________________ -->
8636<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8637 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8638</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8639
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8640<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8641
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8642<h5>Syntax:</h5>
8643<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8644 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8645</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8646
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8647<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8648<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8649 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8650 ensure that it is placed on the stack before local variables.</p>
8651
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8652<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8653<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8654 arguments. The first argument is the value loaded from the stack
8655 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8656 that has enough space to hold the value of the guard.</p>
8657
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8658<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8659<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8660 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8661 stack. This is to ensure that if a local variable on the stack is
8662 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8663 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8664 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8665 function.</p>
8666
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8667</div>
8668
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8669<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8670<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8671 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8672</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8673
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8674<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8675
8676<h5>Syntax:</h5>
8677<pre>
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8678 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;min&gt;)
8679 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;min&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8680</pre>
8681
8682<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8683<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8684 the optimizers to determine at compile time whether a) an operation (like
8685 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8686 runtime check for overflow isn't necessary. An object in this context means
8687 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8688
8689<h5>Arguments:</h5>
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8690<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8691 argument is a pointer to or into the <tt>object</tt>. The second argument
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8692 is a boolean and determines whether <tt>llvm.objectsize</tt> returns 0 (if
8693 true) or -1 (if false) when the object size is unknown.
8694 The second argument only accepts constants.</p>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8695
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8696<h5>Semantics:</h5>
Nuno Lopes30759542012-05-09 15:52:43 +0000[diff] [blame]8697<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to a constant representing
8698 the size of the object concerned. If the size cannot be determined at compile
Nuno Lopes23e75da2012-05-22 15:25:31 +0000[diff] [blame]8699 time, <tt>llvm.objectsize</tt> returns <tt>i32/i64 -1 or 0</tt>
8700 (depending on the <tt>min</tt> argument).</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8701
8702</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8703<!-- _______________________________________________________________________ -->
8704<h4>
8705 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8706</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8707
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8708<div>
8709
8710<h5>Syntax:</h5>
8711<pre>
8712 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8713 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8714</pre>
8715
8716<h5>Overview:</h5>
8717<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8718 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8719
8720<h5>Arguments:</h5>
8721<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8722 argument is a value. The second argument is an expected value, this needs to
8723 be a constant value, variables are not allowed.</p>
8724
8725<h5>Semantics:</h5>
8726<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8727</div>
8728
Nuno Lopesb0c76d72012-07-05 17:37:07 +0000[diff] [blame]8729<!-- _______________________________________________________________________ -->
8730<h4>
8731 <a name="int_donothing">'<tt>llvm.donothing</tt>' Intrinsic</a>
8732</h4>
8733
8734<div>
8735
8736<h5>Syntax:</h5>
8737<pre>
8738 declare void @llvm.donothing() nounwind readnone
8739</pre>
8740
8741<h5>Overview:</h5>
8742<p>The <tt>llvm.donothing</tt> intrinsic doesn't perform any operation. It's the
8743only intrinsic that can be called with an invoke instruction.</p>
8744
8745<h5>Arguments:</h5>
8746<p>None.</p>
8747
8748<h5>Semantics:</h5>
8749<p>This intrinsic does nothing, and it's removed by optimizers and ignored by
8750codegen.</p>
8751</div>
8752
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8753</div>
8754
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8755</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8756<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8757<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8758<address>
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8764 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8765 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8766 Last modified: $Date$
8767</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8768
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8769</body>
8770</html>