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gerrit-public.fairphone.software / platform / external / llvm / dacffb6679ff99fec4cc9c54f4257d2913870d01 / . / docs / LangRef.html
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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.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan 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>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]107 <li><a href="#range">'<tt>range</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]108 </ol>
109 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]110 </ol>
111 </li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]112 <li><a href="#module_flags">Module Flags Metadata</a>
113 <ol>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]114 <li><a href="#objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a></li>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]115 </ol>
116 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]117 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
118 <ol>
119 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]120 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
121 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]122 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
123 Global Variable</a></li>
124 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
125 Global Variable</a></li>
126 </ol>
127 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#instref">Instruction Reference</a>
129 <ol>
130 <li><a href="#terminators">Terminator Instructions</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
133 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]134 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]135 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]136 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]137 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]138 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]139 </ol>
140 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]141 <li><a href="#binaryops">Binary Operations</a>
142 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]144 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]146 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]147 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]148 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]149 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
150 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
151 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]152 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
153 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
154 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]157 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
158 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]159 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
160 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
161 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]162 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]163 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]164 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 <li><a href="#vectorops">Vector Operations</a>
168 <ol>
169 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
170 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
171 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]172 </ol>
173 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]174 <li><a href="#aggregateops">Aggregate Operations</a>
175 <ol>
176 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
177 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
178 </ol>
179 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]180 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]181 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]182 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
183 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
184 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
185 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
186 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
187 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]188 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 </ol>
190 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]191 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]192 <ol>
193 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
194 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
195 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
196 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]198 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
199 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
200 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
201 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]202 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
203 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]204 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]205 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]206 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]207 <li><a href="#otherops">Other Operations</a>
208 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]209 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
210 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]212 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]214 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]215 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]218 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]219 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]220 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]221 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
223 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
225 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
226 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227 </ol>
228 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
230 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]231 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
232 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
233 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]234 </ol>
235 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]236 <li><a href="#int_codegen">Code Generator Intrinsics</a>
237 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]238 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
239 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
240 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
241 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
242 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
243 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]244 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]245 </ol>
246 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]247 <li><a href="#int_libc">Standard C Library Intrinsics</a>
248 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]249 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
252 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]254 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
255 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]257 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
258 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]259 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]260 </ol>
261 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]262 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]264 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]265 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
266 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
267 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]268 </ol>
269 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]270 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
271 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]272 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
273 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
274 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
275 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
276 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]277 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]278 </ol>
279 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]280 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
281 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]282 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
283 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]284 </ol>
285 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]286 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]287 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]288 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]289 <ol>
290 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]291 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]292 </ol>
293 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]294 <li><a href="#int_memorymarkers">Memory Use Markers</a>
295 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]296 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
297 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
298 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
299 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]300 </ol>
301 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]303 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]304 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]306 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]308 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]309 '<tt>llvm.trap</tt>' Intrinsic</a></li>
310 <li><a href="#int_stackprotector">
311 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]312 <li><a href="#int_objectsize">
313 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]314 <li><a href="#int_expect">
315 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]316 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]317 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]318 </ol>
319 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]320</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
322<div class="doc_author">
323 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
324 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]325</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]327<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]328<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]329<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]330
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]331<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]332
333<p>This document is a reference manual for the LLVM assembly language. LLVM is
334 a Static Single Assignment (SSA) based representation that provides type
335 safety, low-level operations, flexibility, and the capability of representing
336 'all' high-level languages cleanly. It is the common code representation
337 used throughout all phases of the LLVM compilation strategy.</p>
338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]341<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]342<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]343<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]344
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]345<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]346
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]347<p>The LLVM code representation is designed to be used in three different forms:
348 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
349 for fast loading by a Just-In-Time compiler), and as a human readable
350 assembly language representation. This allows LLVM to provide a powerful
351 intermediate representation for efficient compiler transformations and
352 analysis, while providing a natural means to debug and visualize the
353 transformations. The three different forms of LLVM are all equivalent. This
354 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]355
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]356<p>The LLVM representation aims to be light-weight and low-level while being
357 expressive, typed, and extensible at the same time. It aims to be a
358 "universal IR" of sorts, by being at a low enough level that high-level ideas
359 may be cleanly mapped to it (similar to how microprocessors are "universal
360 IR's", allowing many source languages to be mapped to them). By providing
361 type information, LLVM can be used as the target of optimizations: for
362 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]363 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]364 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]366<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]367<h4>
368 <a name="wellformed">Well-Formedness</a>
369</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]371<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]373<p>It is important to note that this document describes 'well formed' LLVM
374 assembly language. There is a difference between what the parser accepts and
375 what is considered 'well formed'. For example, the following instruction is
376 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]378<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]379%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]380</pre>
381
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]382<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
383 LLVM infrastructure provides a verification pass that may be used to verify
384 that an LLVM module is well formed. This pass is automatically run by the
385 parser after parsing input assembly and by the optimizer before it outputs
386 bitcode. The violations pointed out by the verifier pass indicate bugs in
387 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]388
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]389</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]390
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]391</div>
392
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]393<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]395<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]396<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]397<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]398
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]399<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]401<p>LLVM identifiers come in two basic types: global and local. Global
402 identifiers (functions, global variables) begin with the <tt>'@'</tt>
403 character. Local identifiers (register names, types) begin with
404 the <tt>'%'</tt> character. Additionally, there are three different formats
405 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]407<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]408 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]409 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
410 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
411 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
412 other characters in their names can be surrounded with quotes. Special
413 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
414 ASCII code for the character in hexadecimal. In this way, any character
415 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]417 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]418 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]419
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]420 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]421 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]422</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]424<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 don't need to worry about name clashes with reserved words, and the set of
426 reserved words may be expanded in the future without penalty. Additionally,
427 unnamed identifiers allow a compiler to quickly come up with a temporary
428 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]429
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]430<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]431 languages. There are keywords for different opcodes
432 ('<tt><a href="#i_add">add</a></tt>',
433 '<tt><a href="#i_bitcast">bitcast</a></tt>',
434 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
435 ('<tt><a href="#t_void">void</a></tt>',
436 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
437 reserved words cannot conflict with variable names, because none of them
438 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
440<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]441 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]452%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453</pre>
454
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]455<p>And the hard 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">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]458%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
459%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]460%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
462
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
464 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]466<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]473 <li>Unnamed temporaries are numbered sequentially</li>
474</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]477 demonstrating instructions, we will follow an instruction with a comment that
478 defines the type and name of value produced. Comments are shown in italic
479 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]481</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482
483<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]484<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]486<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]487<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]488<h3>
489 <a name="modulestructure">Module Structure</a>
490</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]492<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]494<p>LLVM programs are composed of <tt>Module</tt>s, each of which is a
495 translation unit of the input programs. Each module consists of functions,
496 global variables, and symbol table entries. Modules may be combined together
497 with the LLVM linker, which merges function (and global variable)
498 definitions, resolves forward declarations, and merges symbol table
499 entries. Here is an example of the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]501<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502<i>; Declare the string constant as a global constant.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]503<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]504
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]505<i>; External declaration of the puts function</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]506<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]507
508<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]509define i32 @main() { <i>; i32()* </i>&nbsp;
510 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]511 %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]512
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]513 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]514 <a href="#i_call">call</a> i32 @puts(i8* %cast210)
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]515 <a href="#i_ret">ret</a> i32 0&nbsp;
516}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]517
518<i>; Named metadata</i>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]519!1 = metadata !{i32 42}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]520!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]521</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523<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]524 "<tt>.str</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]527 "<tt>foo</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
Bill Wendling4cc2be62012-03-14 08:07:43 +0000[diff] [blame]529<p>In general, a module is made up of a list of global values (where both
530 functions and global variables are global values). Global values are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]531 represented by a pointer to a memory location (in this case, a pointer to an
532 array of char, and a pointer to a function), and have one of the
533 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]535</div>
536
537<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]538<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]539 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]540</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]541
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]542<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]546
547<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]549 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
550 by objects in the current module. In particular, linking code into a
551 module with an private global value may cause the private to be renamed as
552 necessary to avoid collisions. Because the symbol is private to the
553 module, all references can be updated. This doesn't show up in any symbol
554 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]557 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
558 assembler and evaluated by the linker. Unlike normal strong symbols, they
559 are removed by the linker from the final linked image (executable or
560 dynamic library).</dd>
561
562 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
563 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
564 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
565 linker. The symbols are removed by the linker from the final linked image
566 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]567
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]568 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
569 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
570 of the object is not taken. For instance, functions that had an inline
571 definition, but the compiler decided not to inline it. Note,
572 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
573 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
574 visibility. The symbols are removed by the linker from the final linked
575 image (executable or dynamic library).</dd>
576
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]578 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]579 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
580 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]581
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]584 into the object file corresponding to the LLVM module. They exist to
585 allow inlining and other optimizations to take place given knowledge of
586 the definition of the global, which is known to be somewhere outside the
587 module. Globals with <tt>available_externally</tt> linkage are allowed to
588 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
589 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]590
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]591 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]592 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]593 the same name when linkage occurs. This can be used to implement
594 some forms of inline functions, templates, or other code which must be
595 generated in each translation unit that uses it, but where the body may
596 be overridden with a more definitive definition later. Unreferenced
597 <tt>linkonce</tt> globals are allowed to be discarded. Note that
598 <tt>linkonce</tt> linkage does not actually allow the optimizer to
599 inline the body of this function into callers because it doesn't know if
600 this definition of the function is the definitive definition within the
601 program or whether it will be overridden by a stronger definition.
602 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
603 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]604
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]605 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]606 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
607 <tt>linkonce</tt> linkage, except that unreferenced globals with
608 <tt>weak</tt> linkage may not be discarded. This is used for globals that
609 are declared "weak" in C source code.</dd>
610
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]611 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]612 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
613 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
614 global scope.
615 Symbols with "<tt>common</tt>" linkage are merged in the same way as
616 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]617 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]618 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]619 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
620 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]621
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]624 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]625 pointer to array type. When two global variables with appending linkage
626 are linked together, the two global arrays are appended together. This is
627 the LLVM, typesafe, equivalent of having the system linker append together
628 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]629
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]631 <dd>The semantics of this linkage follow the ELF object file model: the symbol
632 is weak until linked, if not linked, the symbol becomes null instead of
633 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]634
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
636 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]637 <dd>Some languages allow differing globals to be merged, such as two functions
638 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]639 that only equivalent globals are ever merged (the "one definition rule"
640 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]641 and <tt>weak_odr</tt> linkage types to indicate that the global will only
642 be merged with equivalent globals. These linkage types are otherwise the
643 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]644
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]645 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]646 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]647 visible, meaning that it participates in linkage and can be used to
648 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]649</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651<p>The next two types of linkage are targeted for Microsoft Windows platform
652 only. They are designed to support importing (exporting) symbols from (to)
653 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]655<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 or variable via a global pointer to a pointer that is set up by the DLL
659 exporting the symbol. On Microsoft Windows targets, the pointer name is
660 formed by combining <code>__imp_</code> and the function or variable
661 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]662
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]663 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]664 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]665 pointer to a pointer in a DLL, so that it can be referenced with the
666 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
667 name is formed by combining <code>__imp_</code> and the function or
668 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]669</dl>
670
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]671<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
672 another module defined a "<tt>.LC0</tt>" variable and was linked with this
673 one, one of the two would be renamed, preventing a collision. Since
674 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
675 declarations), they are accessible outside of the current module.</p>
676
677<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]678 other than <tt>external</tt>, <tt>dllimport</tt>
679 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]680
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]681<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]682 or <tt>weak_odr</tt> linkages.</p>
683
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]684</div>
685
686<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]687<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]688 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]689</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]691<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]694 and <a href="#i_invoke">invokes</a> can all have an optional calling
695 convention specified for the call. The calling convention of any pair of
696 dynamic caller/callee must match, or the behavior of the program is
697 undefined. The following calling conventions are supported by LLVM, and more
698 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699
700<dl>
701 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 specified) matches the target C calling conventions. This calling
704 convention supports varargs function calls and tolerates some mismatch in
705 the declared prototype and implemented declaration of the function (as
706 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707
708 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]709 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]710 (e.g. by passing things in registers). This calling convention allows the
711 target to use whatever tricks it wants to produce fast code for the
712 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]713 (Application Binary Interface).
714 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]715 when this or the GHC convention is used.</a> This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718
719 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]720 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]721 as possible under the assumption that the call is not commonly executed.
722 As such, these calls often preserve all registers so that the call does
723 not break any live ranges in the caller side. This calling convention
724 does not support varargs and requires the prototype of all callees to
725 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]726
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]727 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
728 <dd>This calling convention has been implemented specifically for use by the
729 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
730 It passes everything in registers, going to extremes to achieve this by
731 disabling callee save registers. This calling convention should not be
732 used lightly but only for specific situations such as an alternative to
733 the <em>register pinning</em> performance technique often used when
734 implementing functional programming languages.At the moment only X86
735 supports this convention and it has the following limitations:
736 <ul>
737 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
738 floating point types are supported.</li>
739 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
740 6 floating point parameters.</li>
741 </ul>
742 This calling convention supports
743 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
744 requires both the caller and callee are using it.
745 </dd>
746
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]747 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]748 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749 target-specific calling conventions to be used. Target specific calling
750 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]751</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]752
753<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]754 support Pascal conventions or any other well-known target-independent
755 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]756
757</div>
758
759<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]760<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]762</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]764<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]765
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]766<p>All Global Variables and Functions have one of the following visibility
767 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768
769<dl>
770 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]771 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 that the declaration is visible to other modules and, in shared libraries,
773 means that the declared entity may be overridden. On Darwin, default
774 visibility means that the declaration is visible to other modules. Default
775 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
777 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]778 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 object if they are in the same shared object. Usually, hidden visibility
780 indicates that the symbol will not be placed into the dynamic symbol
781 table, so no other module (executable or shared library) can reference it
782 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]783
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]784 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]785 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]786 the dynamic symbol table, but that references within the defining module
787 will bind to the local symbol. That is, the symbol cannot be overridden by
788 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]789</dl>
790
791</div>
792
793<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]794<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]796</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]797
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]798<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]799
800<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]801 it easier to read the IR and make the IR more condensed (particularly when
802 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]803
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]804<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805%mytype = type { %mytype*, i32 }
806</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]808<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]809 "<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]810 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]811
812<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]813 and that you can therefore specify multiple names for the same type. This
814 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
815 uses structural typing, the name is not part of the type. When printing out
816 LLVM IR, the printer will pick <em>one name</em> to render all types of a
817 particular shape. This means that if you have code where two different
818 source types end up having the same LLVM type, that the dumper will sometimes
819 print the "wrong" or unexpected type. This is an important design point and
820 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]821
822</div>
823
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]824<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]825<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]826 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]827</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]828
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]829<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]830
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]831<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]832 instead of run-time. Global variables may optionally be initialized, may
833 have an explicit section to be placed in, and may have an optional explicit
834 alignment specified. A variable may be defined as "thread_local", which
835 means that it will not be shared by threads (each thread will have a
836 separated copy of the variable). A variable may be defined as a global
837 "constant," which indicates that the contents of the variable
838 will <b>never</b> be modified (enabling better optimization, allowing the
839 global data to be placed in the read-only section of an executable, etc).
840 Note that variables that need runtime initialization cannot be marked
841 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
844 constant, even if the final definition of the global is not. This capability
845 can be used to enable slightly better optimization of the program, but
846 requires the language definition to guarantee that optimizations based on the
847 'constantness' are valid for the translation units that do not include the
848 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]850<p>As SSA values, global variables define pointer values that are in scope
851 (i.e. they dominate) all basic blocks in the program. Global variables
852 always define a pointer to their "content" type because they describe a
853 region of memory, and all memory objects in LLVM are accessed through
854 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]855
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]856<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
857 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]858 like this can be merged with other constants if they have the same
859 initializer. Note that a constant with significant address <em>can</em>
860 be merged with a <tt>unnamed_addr</tt> constant, the result being a
861 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863<p>A global variable may be declared to reside in a target-specific numbered
864 address space. For targets that support them, address spaces may affect how
865 optimizations are performed and/or what target instructions are used to
866 access the variable. The default address space is zero. The address space
867 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]868
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]869<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]870 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]871
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]872<p>An explicit alignment may be specified for a global, which must be a power
873 of 2. If not present, or if the alignment is set to zero, the alignment of
874 the global is set by the target to whatever it feels convenient. If an
875 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]876 alignment. Targets and optimizers are not allowed to over-align the global
877 if the global has an assigned section. In this case, the extra alignment
878 could be observable: for example, code could assume that the globals are
879 densely packed in their section and try to iterate over them as an array,
880 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]881
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]882<p>For example, the following defines a global in a numbered address space with
883 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]884
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]885<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]886@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]887</pre>
888
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889</div>
890
891
892<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]893<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]894 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]895</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]896
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]897<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]898
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]899<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]900 optional <a href="#linkage">linkage type</a>, an optional
901 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>,
903 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904 <a href="#paramattrs">parameter attribute</a> for the return type, a function
905 name, a (possibly empty) argument list (each with optional
906 <a href="#paramattrs">parameter attributes</a>), optional
907 <a href="#fnattrs">function attributes</a>, an optional section, an optional
908 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
909 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
912 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]913 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]914 <a href="#callingconv">calling convention</a>,
915 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]916 <a href="#paramattrs">parameter attribute</a> for the return type, a function
917 name, a possibly empty list of arguments, an optional alignment, and an
918 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]919
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]920<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]921 (Control Flow Graph) for the function. Each basic block may optionally start
922 with a label (giving the basic block a symbol table entry), contains a list
923 of instructions, and ends with a <a href="#terminators">terminator</a>
924 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]925
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]926<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]927 executed on entrance to the function, and it is not allowed to have
928 predecessor basic blocks (i.e. there can not be any branches to the entry
929 block of a function). Because the block can have no predecessors, it also
930 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]931
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]932<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]933 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]934
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]935<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]936 the alignment is set to zero, the alignment of the function is set by the
937 target to whatever it feels convenient. If an explicit alignment is
938 specified, the function is forced to have at least that much alignment. All
939 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]940
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]941<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]942 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]943
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]944<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]945<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]946define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
948 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
949 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
950 [<a href="#gc">gc</a>] { ... }
951</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]952
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]953</div>
954
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]955<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]956<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]957 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]958</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]959
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]960<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]961
962<p>Aliases act as "second name" for the aliasee value (which can be either
963 function, global variable, another alias or bitcast of global value). Aliases
964 may have an optional <a href="#linkage">linkage type</a>, and an
965 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]966
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]967<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]968<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]969@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]970</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]971
972</div>
973
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]974<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]975<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]976 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]977</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]978
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]979<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]980
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]981<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]982 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]983 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]984
985<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]986<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]987; Some unnamed metadata nodes, which are referenced by the named metadata.
988!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]989!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]990!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]991; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]992!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]993</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]994
995</div>
996
997<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]998<h3>
999 <a name="paramattrs">Parameter Attributes</a>
1000</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1001
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1002<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1003
1004<p>The return type and each parameter of a function type may have a set of
1005 <i>parameter attributes</i> associated with them. Parameter attributes are
1006 used to communicate additional information about the result or parameters of
1007 a function. Parameter attributes are considered to be part of the function,
1008 not of the function type, so functions with different parameter attributes
1009 can have the same function type.</p>
1010
1011<p>Parameter attributes are simple keywords that follow the type specified. If
1012 multiple parameter attributes are needed, they are space separated. For
1013 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1014
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1015<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1016declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1017declare i32 @atoi(i8 zeroext)
1018declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1019</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1021<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1022 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1023
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1027 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1028 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1029 should be zero-extended to the extent required by the target's ABI (which
1030 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1031 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1032
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1033 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1034 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1035 should be sign-extended to the extent required by the target's ABI (which
1036 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1037 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1038
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1039 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1040 <dd>This indicates that this parameter or return value should be treated in a
1041 special target-dependent fashion during while emitting code for a function
1042 call or return (usually, by putting it in a register as opposed to memory,
1043 though some targets use it to distinguish between two different kinds of
1044 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1045
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1046 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1047 <dd><p>This indicates that the pointer parameter should really be passed by
1048 value to the function. The attribute implies that a hidden copy of the
1049 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1050 is made between the caller and the callee, so the callee is unable to
1051 modify the value in the callee. This attribute is only valid on LLVM
1052 pointer arguments. It is generally used to pass structs and arrays by
1053 value, but is also valid on pointers to scalars. The copy is considered
1054 to belong to the caller not the callee (for example,
1055 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1056 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1057 values.</p>
1058
1059 <p>The byval attribute also supports specifying an alignment with
1060 the align attribute. It indicates the alignment of the stack slot to
1061 form and the known alignment of the pointer specified to the call site. If
1062 the alignment is not specified, then the code generator makes a
1063 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1065 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This indicates that the pointer parameter specifies the address of a
1067 structure that is the return value of the function in the source program.
1068 This pointer must be guaranteed by the caller to be valid: loads and
1069 stores to the structure may be assumed by the callee to not to trap. This
1070 may only be applied to the first parameter. This is not a valid attribute
1071 for return values. </dd>
1072
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1074 <dd>This indicates that pointer values
1075 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1076 value do not alias pointer values which are not <i>based</i> on it,
1077 ignoring certain "irrelevant" dependencies.
1078 For a call to the parent function, dependencies between memory
1079 references from before or after the call and from those during the call
1080 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1081 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1082 The caller shares the responsibility with the callee for ensuring that
1083 these requirements are met.
1084 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1085 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1086<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1087 Note that this definition of <tt>noalias</tt> is intentionally
1088 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1089 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1090<br>
1091 For function return values, C99's <tt>restrict</tt> is not meaningful,
1092 while LLVM's <tt>noalias</tt> is.
1093 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1094
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1095 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 <dd>This indicates that the callee does not make any copies of the pointer
1097 that outlive the callee itself. This is not a valid attribute for return
1098 values.</dd>
1099
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1100 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This indicates that the pointer parameter can be excised using the
1102 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1103 attribute for return values.</dd>
1104</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1105
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1106</div>
1107
1108<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1109<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1110 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1111</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1112
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1113<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1114
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1115<p>Each function may specify a garbage collector name, which is simply a
1116 string:</p>
1117
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1118<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1119define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1121
1122<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1123 collector which will cause the compiler to alter its output in order to
1124 support the named garbage collection algorithm.</p>
1125
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1126</div>
1127
1128<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1129<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1130 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1131</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1132
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1133<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1135<p>Function attributes are set to communicate additional information about a
1136 function. Function attributes are considered to be part of the function, not
1137 of the function type, so functions with different parameter attributes can
1138 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1139
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1140<p>Function attributes are simple keywords that follow the type specified. If
1141 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1142
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1143<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1144define void @f() noinline { ... }
1145define void @f() alwaysinline { ... }
1146define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1147define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1148</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1149
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1150<dl>
Kostya Serebryany164b86b2012-01-20 17:56:17 +0000[diff] [blame]1151 <dt><tt><b>address_safety</b></tt></dt>
1152 <dd>This attribute indicates that the address safety analysis
1153 is enabled for this function. </dd>
1154
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1155 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1156 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1157 the backend should forcibly align the stack pointer. Specify the
1158 desired alignment, which must be a power of two, in parentheses.
1159
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This attribute indicates that the inliner should attempt to inline this
1162 function into callers whenever possible, ignoring any active inlining size
1163 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1164
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1165 <dt><tt><b>nonlazybind</b></tt></dt>
1166 <dd>This attribute suppresses lazy symbol binding for the function. This
1167 may make calls to the function faster, at the cost of extra program
1168 startup time if the function is not called during program startup.</dd>
1169
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1170 <dt><tt><b>inlinehint</b></tt></dt>
1171 <dd>This attribute indicates that the source code contained a hint that inlining
1172 this function is desirable (such as the "inline" keyword in C/C++). It
1173 is just a hint; it imposes no requirements on the inliner.</dd>
1174
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1175 <dt><tt><b>naked</b></tt></dt>
1176 <dd>This attribute disables prologue / epilogue emission for the function.
1177 This can have very system-specific consequences.</dd>
1178
1179 <dt><tt><b>noimplicitfloat</b></tt></dt>
1180 <dd>This attributes disables implicit floating point instructions.</dd>
1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This attribute indicates that the inliner should never inline this
1184 function in any situation. This attribute may not be used together with
1185 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1186
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1187 <dt><tt><b>noredzone</b></tt></dt>
1188 <dd>This attribute indicates that the code generator should not use a red
1189 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1190
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1191 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1192 <dd>This function attribute indicates that the function never returns
1193 normally. This produces undefined behavior at runtime if the function
1194 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This function attribute indicates that the function never returns with an
1198 unwind or exceptional control flow. If the function does unwind, its
1199 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1200
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1201 <dt><tt><b>optsize</b></tt></dt>
1202 <dd>This attribute suggests that optimization passes and code generator passes
1203 make choices that keep the code size of this function low, and otherwise
1204 do optimizations specifically to reduce code size.</dd>
1205
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1206 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1207 <dd>This attribute indicates that the function computes its result (or decides
1208 to unwind an exception) based strictly on its arguments, without
1209 dereferencing any pointer arguments or otherwise accessing any mutable
1210 state (e.g. memory, control registers, etc) visible to caller functions.
1211 It does not write through any pointer arguments
1212 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1213 changes any state visible to callers. This means that it cannot unwind
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1214 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1215
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1216 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1217 <dd>This attribute indicates that the function does not write through any
1218 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1219 arguments) or otherwise modify any state (e.g. memory, control registers,
1220 etc) visible to caller functions. It may dereference pointer arguments
1221 and read state that may be set in the caller. A readonly function always
1222 returns the same value (or unwinds an exception identically) when called
1223 with the same set of arguments and global state. It cannot unwind an
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]1224 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1225
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1226 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1227 <dd>This attribute indicates that this function can return twice. The
1228 C <code>setjmp</code> is an example of such a function. The compiler
1229 disables some optimizations (like tail calls) in the caller of these
1230 functions.</dd>
1231
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1232 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1233 <dd>This attribute indicates that the function should emit a stack smashing
1234 protector. It is in the form of a "canary"&mdash;a random value placed on
1235 the stack before the local variables that's checked upon return from the
1236 function to see if it has been overwritten. A heuristic is used to
1237 determine if a function needs stack protectors or not.<br>
1238<br>
1239 If a function that has an <tt>ssp</tt> attribute is inlined into a
1240 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1241 function will have an <tt>ssp</tt> attribute.</dd>
1242
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1243 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244 <dd>This attribute indicates that the function should <em>always</em> emit a
1245 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1246 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1247<br>
1248 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1249 function that doesn't have an <tt>sspreq</tt> attribute or which has
1250 an <tt>ssp</tt> attribute, then the resulting function will have
1251 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1252
1253 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1254 <dd>This attribute indicates that the ABI being targeted requires that
1255 an unwind table entry be produce for this function even if we can
1256 show that no exceptions passes by it. This is normally the case for
1257 the ELF x86-64 abi, but it can be disabled for some compilation
1258 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1259</dl>
1260
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1261</div>
1262
1263<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1264<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1265 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1266</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1267
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1268<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1269
1270<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1271 the GCC "file scope inline asm" blocks. These blocks are internally
1272 concatenated by LLVM and treated as a single unit, but may be separated in
1273 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1274
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1275<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1276module asm "inline asm code goes here"
1277module asm "more can go here"
1278</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1279
1280<p>The strings can contain any character by escaping non-printable characters.
1281 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]1282 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1283
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1284<p>The inline asm code is simply printed to the machine code .s file when
1285 assembly code is generated.</p>
1286
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1287</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1290<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1291 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1292</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1294<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1296<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1297 data is to be laid out in memory. The syntax for the data layout is
1298 simply:</p>
1299
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1300<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1301target datalayout = "<i>layout specification</i>"
1302</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303
1304<p>The <i>layout specification</i> consists of a list of specifications
1305 separated by the minus sign character ('-'). Each specification starts with
1306 a letter and may include other information after the letter to define some
1307 aspect of the data layout. The specifications accepted are as follows:</p>
1308
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1309<dl>
1310 <dt><tt>E</tt></dt>
1311 <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]1312 bits with the most significance have the lowest address location.</dd>
1313
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1314 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1315 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1316 the bits with the least significance have the lowest address
1317 location.</dd>
1318
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1319 <dt><tt>S<i>size</i></tt></dt>
1320 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1321 of stack variables is limited to the natural stack alignment to avoid
1322 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1323 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1324 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1325
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1326 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1327 <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]1328 <i>preferred</i> alignments. All sizes are in bits. Specifying
1329 the <i>pref</i> alignment is optional. If omitted, the
1330 preceding <tt>:</tt> should be omitted too.</dd>
1331
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1332 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1333 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1334 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1335
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1336 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1337 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338 <i>size</i>.</dd>
1339
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1341 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1342 <i>size</i>. Only values of <i>size</i> that are supported by the target
1343 will work. 32 (float) and 64 (double) are supported on all targets;
1344 80 or 128 (different flavors of long double) are also supported on some
1345 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1346
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1347 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1348 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1349 <i>size</i>.</dd>
1350
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1351 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1352 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1353 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1354
1355 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1356 <dd>This specifies a set of native integer widths for the target CPU
1357 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1358 "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]1359 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1360 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1361</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1362
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1363<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1364 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1365 specifications in the <tt>datalayout</tt> keyword. The default specifications
1366 are given in this list:</p>
1367
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1368<ul>
1369 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1370 <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]1371 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1372 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1373 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1374 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1375 <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]1376 alignment of 64-bits</li>
1377 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1378 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1379 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1380 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1381 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1382 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1383</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1384
1385<p>When LLVM is determining the alignment for a given type, it uses the
1386 following rules:</p>
1387
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1388<ol>
1389 <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]1390 specification is used.</li>
1391
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1392 <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]1393 smallest integer type that is larger than the bitwidth of the sought type
1394 is used. If none of the specifications are larger than the bitwidth then
1395 the the largest integer type is used. For example, given the default
1396 specifications above, the i7 type will use the alignment of i8 (next
1397 largest) while both i65 and i256 will use the alignment of i64 (largest
1398 specified).</li>
1399
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1400 <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]1401 largest vector type that is smaller than the sought vector type will be
1402 used as a fall back. This happens because &lt;128 x double&gt; can be
1403 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1404</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1405
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1406<p>The function of the data layout string may not be what you expect. Notably,
1407 this is not a specification from the frontend of what alignment the code
1408 generator should use.</p>
1409
1410<p>Instead, if specified, the target data layout is required to match what the
1411 ultimate <em>code generator</em> expects. This string is used by the
1412 mid-level optimizers to
1413 improve code, and this only works if it matches what the ultimate code
1414 generator uses. If you would like to generate IR that does not embed this
1415 target-specific detail into the IR, then you don't have to specify the
1416 string. This will disable some optimizations that require precise layout
1417 information, but this also prevents those optimizations from introducing
1418 target specificity into the IR.</p>
1419
1420
1421
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1422</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1423
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1424<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1425<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1427</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1428
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1429<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1430
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1431<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1432with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1433is undefined. Pointer values are associated with address ranges
1434according to the following rules:</p>
1435
1436<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1437 <li>A pointer value is associated with the addresses associated with
1438 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1439 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1440 range of the variable's storage.</li>
1441 <li>The result value of an allocation instruction is associated with
1442 the address range of the allocated storage.</li>
1443 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1444 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1445 <li>An integer constant other than zero or a pointer value returned
1446 from a function not defined within LLVM may be associated with address
1447 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1448 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1449 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1450</ul>
1451
1452<p>A pointer value is <i>based</i> on another pointer value according
1453 to the following rules:</p>
1454
1455<ul>
1456 <li>A pointer value formed from a
1457 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1458 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1459 <li>The result value of a
1460 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1461 of the <tt>bitcast</tt>.</li>
1462 <li>A pointer value formed by an
1463 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1464 pointer values that contribute (directly or indirectly) to the
1465 computation of the pointer's value.</li>
1466 <li>The "<i>based</i> on" relationship is transitive.</li>
1467</ul>
1468
1469<p>Note that this definition of <i>"based"</i> is intentionally
1470 similar to the definition of <i>"based"</i> in C99, though it is
1471 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1472
1473<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1474<tt><a href="#i_load">load</a></tt> merely indicates the size and
1475alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1476interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1477<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1478and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1479
1480<p>Consequently, type-based alias analysis, aka TBAA, aka
1481<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1482LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1483additional information which specialized optimization passes may use
1484to implement type-based alias analysis.</p>
1485
1486</div>
1487
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1488<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1489<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1490 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1491</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1492
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1493<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1494
1495<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1496href="#i_store"><tt>store</tt></a>s, and <a
1497href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1498The optimizers must not change the number of volatile operations or change their
1499order of execution relative to other volatile operations. The optimizers
1500<i>may</i> change the order of volatile operations relative to non-volatile
1501operations. This is not Java's "volatile" and has no cross-thread
1502synchronization behavior.</p>
1503
1504</div>
1505
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1506<!-- ======================================================================= -->
1507<h3>
1508 <a name="memmodel">Memory Model for Concurrent Operations</a>
1509</h3>
1510
1511<div>
1512
1513<p>The LLVM IR does not define any way to start parallel threads of execution
1514or to register signal handlers. Nonetheless, there are platform-specific
1515ways to create them, and we define LLVM IR's behavior in their presence. This
1516model is inspired by the C++0x memory model.</p>
1517
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1518<p>For a more informal introduction to this model, see the
1519<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1520
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1521<p>We define a <i>happens-before</i> partial order as the least partial order
1522that</p>
1523<ul>
1524 <li>Is a superset of single-thread program order, and</li>
1525 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1526 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1527 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1528 creation, thread joining, etc., and by atomic instructions.
1529 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1530 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1531</ul>
1532
1533<p>Note that program order does not introduce <i>happens-before</i> edges
1534between a thread and signals executing inside that thread.</p>
1535
1536<p>Every (defined) read operation (load instructions, memcpy, atomic
1537loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1538(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1539stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1540initialized globals are considered to have a write of the initializer which is
1541atomic and happens before any other read or write of the memory in question.
1542For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1543any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1544
1545<ul>
1546 <li>If <var>write<sub>1</sub></var> happens before
1547 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1548 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1549 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1550 <li>If <var>R<sub>byte</sub></var> happens before
1551 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1552 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1553</ul>
1554
1555<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1556<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1557 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1558 is supposed to give guarantees which can support
1559 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1560 addresses which do not behave like normal memory. It does not generally
1561 provide cross-thread synchronization.)
1562 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1563 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1564 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1565 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1566 <var>R<sub>byte</sub></var> returns the value written by that
1567 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1568 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1569 <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]1570 values written. See the <a href="#ordering">Atomic Memory Ordering
1571 Constraints</a> section for additional constraints on how the choice
1572 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1573 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1574</ul>
1575
1576<p><var>R</var> returns the value composed of the series of bytes it read.
1577This implies that some bytes within the value may be <tt>undef</tt>
1578<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1579defines the semantics of the operation; it doesn't mean that targets will
1580emit more than one instruction to read the series of bytes.</p>
1581
1582<p>Note that in cases where none of the atomic intrinsics are used, this model
1583places only one restriction on IR transformations on top of what is required
1584for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1585otherwise be stored is not allowed in general. (Specifically, in the case
1586where another thread might write to and read from an address, introducing a
1587store can change a load that may see exactly one write into a load that may
1588see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1589
1590<!-- FIXME: This model assumes all targets where concurrency is relevant have
1591a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1592none of the backends currently in the tree fall into this category; however,
1593there might be targets which care. If there are, we want a paragraph
1594like the following:
1595
1596Targets may specify that stores narrower than a certain width are not
1597available; on such a target, for the purposes of this model, treat any
1598non-atomic write with an alignment or width less than the minimum width
1599as if it writes to the relevant surrounding bytes.
1600-->
1601
1602</div>
1603
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1604<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1605<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1606 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1607</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1608
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1609<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1610
1611<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1612<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1613<a href="#i_fence"><code>fence</code></a>,
1614<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1615<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1616that determines which other atomic instructions on the same address they
1617<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1618but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1619check those specs (see spec references in the
Nick Lewycky300a2632012-01-23 08:47:21 +0000[diff] [blame]1620<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1621<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1622treat these orderings somewhat differently since they don't take an address.
1623See that instruction's documentation for details.</p>
1624
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1625<p>For a simpler introduction to the ordering constraints, see the
1626<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1627
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1628<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1629<dt><code>unordered</code></dt>
1630<dd>The set of values that can be read is governed by the happens-before
1631partial order. A value cannot be read unless some operation wrote it.
1632This is intended to provide a guarantee strong enough to model Java's
1633non-volatile shared variables. This ordering cannot be specified for
1634read-modify-write operations; it is not strong enough to make them atomic
1635in any interesting way.</dd>
1636<dt><code>monotonic</code></dt>
1637<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1638total order for modifications by <code>monotonic</code> operations on each
1639address. All modification orders must be compatible with the happens-before
1640order. There is no guarantee that the modification orders can be combined to
1641a global total order for the whole program (and this often will not be
1642possible). The read in an atomic read-modify-write operation
1643(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1644<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1645reads the value in the modification order immediately before the value it
1646writes. If one atomic read happens before another atomic read of the same
1647address, the later read must see the same value or a later value in the
1648address's modification order. This disallows reordering of
1649<code>monotonic</code> (or stronger) operations on the same address. If an
1650address is written <code>monotonic</code>ally by one thread, and other threads
1651<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1652eventually see the write. This corresponds to the C++0x/C1x
1653<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1654<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1655<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1656a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1657operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1658<dt><code>release</code></dt>
1659<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1660writes a value which is subsequently read by an <code>acquire</code> operation,
1661it <i>synchronizes-with</i> that operation. (This isn't a complete
1662description; see the C++0x definition of a release sequence.) This corresponds
1663to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1664<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1665<code>acquire</code> and <code>release</code> operation on its address.
1666This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1667<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1668<dd>In addition to the guarantees of <code>acq_rel</code>
1669(<code>acquire</code> for an operation which only reads, <code>release</code>
1670for an operation which only writes), there is a global total order on all
1671sequentially-consistent operations on all addresses, which is consistent with
1672the <i>happens-before</i> partial order and with the modification orders of
1673all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1674preceding write to the same address in this global order. This corresponds
1675to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1676</dl>
1677
1678<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1679it only <i>synchronizes with</i> or participates in modification and seq_cst
1680total orderings with other operations running in the same thread (for example,
1681in signal handlers).</p>
1682
1683</div>
1684
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1685</div>
1686
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1688<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1689<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1690
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1691<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1693<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1694 intermediate representation. Being typed enables a number of optimizations
1695 to be performed on the intermediate representation directly, without having
1696 to do extra analyses on the side before the transformation. A strong type
1697 system makes it easier to read the generated code and enables novel analyses
1698 and transformations that are not feasible to perform on normal three address
1699 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1700
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1701<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1702<h3>
1703 <a name="t_classifications">Type Classifications</a>
1704</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1705
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1706<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1707
1708<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1709
1710<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1711 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1712 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1714 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1715 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1716 </tr>
1717 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1718 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1719 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1720 </tr>
1721 <tr>
1722 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1723 <td><a href="#t_integer">integer</a>,
1724 <a href="#t_floating">floating point</a>,
1725 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1726 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1727 <a href="#t_struct">structure</a>,
1728 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1729 <a href="#t_label">label</a>,
1730 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1731 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1733 <tr>
1734 <td><a href="#t_primitive">primitive</a></td>
1735 <td><a href="#t_label">label</a>,
1736 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1737 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1738 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1739 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1740 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1741 </tr>
1742 <tr>
1743 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1744 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1745 <a href="#t_function">function</a>,
1746 <a href="#t_pointer">pointer</a>,
1747 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1748 <a href="#t_vector">vector</a>,
1749 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1750 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1751 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1752 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1754
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1755<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1756 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1757 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1758
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1759</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1760
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1761<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1762<h3>
1763 <a name="t_primitive">Primitive Types</a>
1764</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1765
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1766<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1768<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1769 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1770
1771<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1772<h4>
1773 <a name="t_integer">Integer Type</a>
1774</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1775
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1776<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1777
1778<h5>Overview:</h5>
1779<p>The integer type is a very simple type that simply specifies an arbitrary
1780 bit width for the integer type desired. Any bit width from 1 bit to
1781 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1782
1783<h5>Syntax:</h5>
1784<pre>
1785 iN
1786</pre>
1787
1788<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1789 value.</p>
1790
1791<h5>Examples:</h5>
1792<table class="layout">
1793 <tr class="layout">
1794 <td class="left"><tt>i1</tt></td>
1795 <td class="left">a single-bit integer.</td>
1796 </tr>
1797 <tr class="layout">
1798 <td class="left"><tt>i32</tt></td>
1799 <td class="left">a 32-bit integer.</td>
1800 </tr>
1801 <tr class="layout">
1802 <td class="left"><tt>i1942652</tt></td>
1803 <td class="left">a really big integer of over 1 million bits.</td>
1804 </tr>
1805</table>
1806
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1807</div>
1808
1809<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1810<h4>
1811 <a name="t_floating">Floating Point Types</a>
1812</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1813
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1814<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1815
1816<table>
1817 <tbody>
1818 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1819 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1820 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1821 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1822 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1823 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1824 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1825 </tbody>
1826</table>
1827
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1828</div>
1829
1830<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1831<h4>
1832 <a name="t_x86mmx">X86mmx Type</a>
1833</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1834
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1835<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1836
1837<h5>Overview:</h5>
1838<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>
1839
1840<h5>Syntax:</h5>
1841<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1842 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1843</pre>
1844
1845</div>
1846
1847<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1848<h4>
1849 <a name="t_void">Void Type</a>
1850</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1852<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1853
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1854<h5>Overview:</h5>
1855<p>The void type does not represent any value and has no size.</p>
1856
1857<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1858<pre>
1859 void
1860</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1861
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1862</div>
1863
1864<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1865<h4>
1866 <a name="t_label">Label Type</a>
1867</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1868
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1869<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1870
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1871<h5>Overview:</h5>
1872<p>The label type represents code labels.</p>
1873
1874<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1875<pre>
1876 label
1877</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1878
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1879</div>
1880
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1881<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1882<h4>
1883 <a name="t_metadata">Metadata Type</a>
1884</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1885
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1886<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1887
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1888<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1889<p>The metadata type represents embedded metadata. No derived types may be
1890 created from metadata except for <a href="#t_function">function</a>
1891 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1892
1893<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1894<pre>
1895 metadata
1896</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1897
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1898</div>
1899
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1900</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1901
1902<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1903<h3>
1904 <a name="t_derived">Derived Types</a>
1905</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1906
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1907<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1908
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1909<p>The real power in LLVM comes from the derived types in the system. This is
1910 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1911 useful types. Each of these types contain one or more element types which
1912 may be a primitive type, or another derived type. For example, it is
1913 possible to have a two dimensional array, using an array as the element type
1914 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1915
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1916<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1917<h4>
1918 <a name="t_aggregate">Aggregate Types</a>
1919</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1920
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1921<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1922
1923<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1924 member types. <a href="#t_array">Arrays</a> and
1925 <a href="#t_struct">structs</a> are aggregate types.
1926 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1927
1928</div>
1929
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1930<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1931<h4>
1932 <a name="t_array">Array Type</a>
1933</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1934
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1935<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1937<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1939 sequentially in memory. The array type requires a size (number of elements)
1940 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1942<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1943<pre>
1944 [&lt;# elements&gt; x &lt;elementtype&gt;]
1945</pre>
1946
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1947<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1948 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1949
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1950<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1951<table class="layout">
1952 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1953 <td class="left"><tt>[40 x i32]</tt></td>
1954 <td class="left">Array of 40 32-bit integer values.</td>
1955 </tr>
1956 <tr class="layout">
1957 <td class="left"><tt>[41 x i32]</tt></td>
1958 <td class="left">Array of 41 32-bit integer values.</td>
1959 </tr>
1960 <tr class="layout">
1961 <td class="left"><tt>[4 x i8]</tt></td>
1962 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1963 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1964</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1965<p>Here are some examples of multidimensional arrays:</p>
1966<table class="layout">
1967 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1968 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1969 <td class="left">3x4 array of 32-bit integer values.</td>
1970 </tr>
1971 <tr class="layout">
1972 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1973 <td class="left">12x10 array of single precision floating point values.</td>
1974 </tr>
1975 <tr class="layout">
1976 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1977 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1978 </tr>
1979</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1980
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1981<p>There is no restriction on indexing beyond the end of the array implied by
1982 a static type (though there are restrictions on indexing beyond the bounds
1983 of an allocated object in some cases). This means that single-dimension
1984 'variable sized array' addressing can be implemented in LLVM with a zero
1985 length array type. An implementation of 'pascal style arrays' in LLVM could
1986 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1987
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1988</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1991<h4>
1992 <a name="t_function">Function Type</a>
1993</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1994
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1995<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1996
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1998<p>The function type can be thought of as a function signature. It consists of
1999 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]2000 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]2001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2002<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2003<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2004 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2005</pre>
2006
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2007<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]2008 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2009 which indicates that the function takes a variable number of arguments.
2010 Variable argument functions can access their arguments with
2011 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2012 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2013 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2014
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2015<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2016<table class="layout">
2017 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2018 <td class="left"><tt>i32 (i32)</tt></td>
2019 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2020 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2021 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2022 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2023 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2024 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2025 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2026 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2027 </td>
2028 </tr><tr class="layout">
2029 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2030 <td class="left">A vararg function that takes at least one
2031 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2032 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2033 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2034 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2035 </tr><tr class="layout">
2036 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2037 <td class="left">A function taking an <tt>i32</tt>, returning a
2038 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2039 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2040 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2041</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2042
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2043</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2045<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2046<h4>
2047 <a name="t_struct">Structure Type</a>
2048</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2049
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2050<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2051
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2052<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2053<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2054 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]2055
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2056<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2057 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2058 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2059 Structures in registers are accessed using the
2060 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2061 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2062
2063<p>Structures may optionally be "packed" structures, which indicate that the
2064 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2065 the elements. In non-packed structs, padding between field types is inserted
2066 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2067 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2068
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2069<p>Structures can either be "literal" or "identified". A literal structure is
2070 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2071 types are always defined at the top level with a name. Literal types are
2072 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2073 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]2074 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2075</p>
2076
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2077<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2078<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2079 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2080 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2081</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2082
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2083<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2084<table class="layout">
2085 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2086 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2087 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2088 </tr>
2089 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2090 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2091 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2092 second element is a <a href="#t_pointer">pointer</a> to a
2093 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2094 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2095 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2096 <tr class="layout">
2097 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2098 <td class="left">A packed struct known to be 5 bytes in size.</td>
2099 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2100</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2101
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2102</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2103
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2104<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2105<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2106 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2107</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2109<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2110
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2111<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2112<p>Opaque structure types are used to represent named structure types that do
2113 not have a body specified. This corresponds (for example) to the C notion of
2114 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2115
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2116<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2117<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2118 %X = type opaque
2119 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2120</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2121
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2122<h5>Examples:</h5>
2123<table class="layout">
2124 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2125 <td class="left"><tt>opaque</tt></td>
2126 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2127 </tr>
2128</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2129
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2130</div>
2131
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2132
2133
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2134<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2135<h4>
2136 <a name="t_pointer">Pointer Type</a>
2137</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2138
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2139<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2140
2141<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2142<p>The pointer type is used to specify memory locations.
2143 Pointers are commonly used to reference objects in memory.</p>
2144
2145<p>Pointer types may have an optional address space attribute defining the
2146 numbered address space where the pointed-to object resides. The default
2147 address space is number zero. The semantics of non-zero address
2148 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2149
2150<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2151 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2152
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2153<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2154<pre>
2155 &lt;type&gt; *
2156</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2157
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2158<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2159<table class="layout">
2160 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2161 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2162 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2163 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2164 </tr>
2165 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2166 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2167 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2168 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2169 <tt>i32</tt>.</td>
2170 </tr>
2171 <tr class="layout">
2172 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2173 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2174 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2175 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2176</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2178</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2179
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2180<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2181<h4>
2182 <a name="t_vector">Vector Type</a>
2183</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2185<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2186
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2187<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2188<p>A vector type is a simple derived type that represents a vector of elements.
2189 Vector types are used when multiple primitive data are operated in parallel
2190 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2191 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2192 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2193
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2194<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2195<pre>
2196 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2197</pre>
2198
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2199<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2200 may be any integer or floating point type, or a pointer to these types.
2201 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2202
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2203<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2204<table class="layout">
2205 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2206 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2207 <td class="left">Vector of 4 32-bit integer values.</td>
2208 </tr>
2209 <tr class="layout">
2210 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2211 <td class="left">Vector of 8 32-bit floating-point values.</td>
2212 </tr>
2213 <tr class="layout">
2214 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2215 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2216 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2217 <tr class="layout">
2218 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2219 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2220 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2221</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2222
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2223</div>
2224
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2225</div>
2226
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2227</div>
2228
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2229<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2230<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2231<!-- *********************************************************************** -->
2232
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2233<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2234
2235<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2236 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2237
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2238<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2239<h3>
2240 <a name="simpleconstants">Simple Constants</a>
2241</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2242
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2243<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2244
2245<dl>
2246 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2247 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2248 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2249
2250 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2251 <dd>Standard integers (such as '4') are constants of
2252 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2253 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2254
2255 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2256 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2257 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2258 notation (see below). The assembler requires the exact decimal value of a
2259 floating-point constant. For example, the assembler accepts 1.25 but
2260 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2261 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2262
2263 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2264 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2265 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2266</dl>
2267
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2268<p>The one non-intuitive notation for constants is the hexadecimal form of
2269 floating point constants. For example, the form '<tt>double
2270 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2271 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2272 constants are required (and the only time that they are generated by the
2273 disassembler) is when a floating point constant must be emitted but it cannot
2274 be represented as a decimal floating point number in a reasonable number of
2275 digits. For example, NaN's, infinities, and other special values are
2276 represented in their IEEE hexadecimal format so that assembly and disassembly
2277 do not cause any bits to change in the constants.</p>
2278
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2279<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2280 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2281 representation for double); half and float values must, however, be exactly
2282 representable as IEE754 half and single precision, respectively.
2283 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2284 for long double, and there are three forms of long double. The 80-bit format
2285 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2286 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2287 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2288 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2289 currently supported target uses this format. Long doubles will only work if
2290 they match the long double format on your target. All hexadecimal formats
2291 are big-endian (sign bit at the left).</p>
2292
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2293<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2294</div>
2295
2296<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2297<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2298<a name="aggregateconstants"></a> <!-- old anchor -->
2299<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2300</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2301
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2302<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2304<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2306
2307<dl>
2308 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2309 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2310 type definitions (a comma separated list of elements, surrounded by braces
2311 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2312 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2313 Structure constants must have <a href="#t_struct">structure type</a>, and
2314 the number and types of elements must match those specified by the
2315 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2316
2317 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2318 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2319 definitions (a comma separated list of elements, surrounded by square
2320 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2321 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2322 the number and types of elements must match those specified by the
2323 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2324
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2325 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2326 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2327 definitions (a comma separated list of elements, surrounded by
2328 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2329 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2330 have <a href="#t_vector">vector type</a>, and the number and types of
2331 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2332
2333 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2334 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2335 value to zero of <em>any</em> type, including scalar and
2336 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2337 This is often used to avoid having to print large zero initializers
2338 (e.g. for large arrays) and is always exactly equivalent to using explicit
2339 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2340
2341 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2342 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2343 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2344 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2345 be interpreted as part of the instruction stream, metadata is a place to
2346 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2347</dl>
2348
2349</div>
2350
2351<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2352<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2353 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2354</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2355
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2356<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2357
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2358<p>The addresses of <a href="#globalvars">global variables</a>
2359 and <a href="#functionstructure">functions</a> are always implicitly valid
2360 (link-time) constants. These constants are explicitly referenced when
2361 the <a href="#identifiers">identifier for the global</a> is used and always
2362 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2363 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2364
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2365<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2366@X = global i32 17
2367@Y = global i32 42
2368@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2369</pre>
2370
2371</div>
2372
2373<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2374<h3>
2375 <a name="undefvalues">Undefined Values</a>
2376</h3>
2377
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2378<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2379
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2380<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]2381 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2382 Undefined values may be of any type (other than '<tt>label</tt>'
2383 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2384
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2385<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2386 program is well defined no matter what value is used. This gives the
2387 compiler more freedom to optimize. Here are some examples of (potentially
2388 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2389
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2390
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2391<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2392 %A = add %X, undef
2393 %B = sub %X, undef
2394 %C = xor %X, undef
2395Safe:
2396 %A = undef
2397 %B = undef
2398 %C = undef
2399</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2400
2401<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]2402 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]2403
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2404<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2405 %A = or %X, undef
2406 %B = and %X, undef
2407Safe:
2408 %A = -1
2409 %B = 0
2410Unsafe:
2411 %A = undef
2412 %B = undef
2413</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2414
2415<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2416 For example, if <tt>%X</tt> has a zero bit, then the output of the
2417 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2418 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2419 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2420 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2421 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2422 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2423 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2424
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2425<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2426 %A = select undef, %X, %Y
2427 %B = select undef, 42, %Y
2428 %C = select %X, %Y, undef
2429Safe:
2430 %A = %X (or %Y)
2431 %B = 42 (or %Y)
2432 %C = %Y
2433Unsafe:
2434 %A = undef
2435 %B = undef
2436 %C = undef
2437</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2438
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2439<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2440 branch) conditions can go <em>either way</em>, but they have to come from one
2441 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2442 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2443 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2444 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2445 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2446 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2447
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2448<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2449 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2450
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2451 %B = undef
2452 %C = xor %B, %B
2453
2454 %D = undef
2455 %E = icmp lt %D, 4
2456 %F = icmp gte %D, 4
2457
2458Safe:
2459 %A = undef
2460 %B = undef
2461 %C = undef
2462 %D = undef
2463 %E = undef
2464 %F = undef
2465</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2466
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2467<p>This example points out that two '<tt>undef</tt>' operands are not
2468 necessarily the same. This can be surprising to people (and also matches C
2469 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2470 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2471 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2472 its value over its "live range". This is true because the variable doesn't
2473 actually <em>have a live range</em>. Instead, the value is logically read
2474 from arbitrary registers that happen to be around when needed, so the value
2475 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2476 need to have the same semantics or the core LLVM "replace all uses with"
2477 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2478
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2479<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2480 %A = fdiv undef, %X
2481 %B = fdiv %X, undef
2482Safe:
2483 %A = undef
2484b: unreachable
2485</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2486
2487<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2488 value</em> and <em>undefined behavior</em>. An undefined value (like
2489 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2490 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2491 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2492 defined on SNaN's. However, in the second example, we can make a more
2493 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2494 arbitrary value, we are allowed to assume that it could be zero. Since a
2495 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2496 the operation does not execute at all. This allows us to delete the divide and
2497 all code after it. Because the undefined operation "can't happen", the
2498 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2499
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2500<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2501a: store undef -> %X
2502b: store %X -> undef
2503Safe:
2504a: &lt;deleted&gt;
2505b: unreachable
2506</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2507
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2508<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2509 undefined value can be assumed to not have any effect; we can assume that the
2510 value is overwritten with bits that happen to match what was already there.
2511 However, a store <em>to</em> an undefined location could clobber arbitrary
2512 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2513
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2514</div>
2515
2516<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2517<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2518 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2519</h3>
2520
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2521<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2522
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2523<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2524 they also represent the fact that an instruction or constant expression which
2525 cannot evoke side effects has nevertheless detected a condition which results
2526 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2527
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2528<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]2529 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2530 <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]2531
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2532<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2533
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2534<ul>
2535<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2536 their operands.</li>
2537
2538<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2539 to their dynamic predecessor basic block.</li>
2540
2541<li>Function arguments depend on the corresponding actual argument values in
2542 the dynamic callers of their functions.</li>
2543
2544<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2545 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2546 control back to them.</li>
2547
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2548<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]2549 <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]2550 or exception-throwing call instructions that dynamically transfer control
2551 back to them.</li>
2552
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2553<li>Non-volatile loads and stores depend on the most recent stores to all of the
2554 referenced memory addresses, following the order in the IR
2555 (including loads and stores implied by intrinsics such as
2556 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2557
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2558<!-- TODO: In the case of multiple threads, this only applies if the store
2559 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2560
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2561<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2562
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2563<li>An instruction with externally visible side effects depends on the most
2564 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2565 the order in the IR. (This includes
2566 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2567
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2568<li>An instruction <i>control-depends</i> on a
2569 <a href="#terminators">terminator instruction</a>
2570 if the terminator instruction has multiple successors and the instruction
2571 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2572 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2573
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2574<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2575 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2576 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2577 successor.</li>
2578
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2579<li>Dependence is transitive.</li>
2580
2581</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2582
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2583<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2584 with the additional affect that any instruction which has a <i>dependence</i>
2585 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2586
2587<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2588
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2589<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2590entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2591 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2592 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2593 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2594 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2595
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2596 store i32 %poison, i32* @g ; Poison value stored to memory.
2597 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2598
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2599 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2600
2601 %narrowaddr = bitcast i32* @g to i16*
2602 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2603 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2604 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2605
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2606 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2607 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2608
2609true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2610 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2611 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2612 br label %end
2613
2614end:
2615 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2616 ; Both edges into this PHI are
2617 ; control-dependent on %cmp, so this
2618 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2619
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2620 store volatile i32 0, i32* @g ; This would depend on the store in %true
2621 ; if %cmp is true, or the store in %entry
2622 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2623
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2624 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2625 ; The same branch again, but this time the
2626 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2627
2628second_true:
2629 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2630 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2631
2632second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2633 store volatile i32 0, i32* @g ; This time, the instruction always depends
2634 ; on the store in %end. Also, it is
2635 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2636 ; well-defined (ignoring earlier undefined
2637 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2638</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2639
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2640</div>
2641
2642<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2643<h3>
2644 <a name="blockaddress">Addresses of Basic Blocks</a>
2645</h3>
2646
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2647<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2648
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2649<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2650
2651<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2652 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2653 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2654
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2655<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2656 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2657 comparisons against null. Pointer equality tests between labels addresses
2658 results in undefined behavior &mdash; though, again, comparison against null
2659 is ok, and no label is equal to the null pointer. This may be passed around
2660 as an opaque pointer sized value as long as the bits are not inspected. This
2661 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2662 long as the original value is reconstituted before the <tt>indirectbr</tt>
2663 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2664
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2665<p>Finally, some targets may provide defined semantics when using the value as
2666 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2667
2668</div>
2669
2670
2671<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2672<h3>
2673 <a name="constantexprs">Constant Expressions</a>
2674</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2676<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2677
2678<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2679 to be used as constants. Constant expressions may be of
2680 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2681 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2682 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2683
2684<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2685 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2686 <dd>Truncate a constant to another type. The bit size of CST must be larger
2687 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2688
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2689 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2690 <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]2691 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2692
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2693 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2694 <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]2695 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2696
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2697 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2698 <dd>Truncate a floating point constant to another floating point type. The
2699 size of CST must be larger than the size of TYPE. Both types must be
2700 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2701
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2702 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2703 <dd>Floating point extend a constant to another type. The size of CST must be
2704 smaller or equal to the size of TYPE. Both types must be floating
2705 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2706
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2707 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2708 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2709 constant. TYPE must be a scalar or vector integer type. CST must be of
2710 scalar or vector floating point type. Both CST and TYPE must be scalars,
2711 or vectors of the same number of elements. If the value won't fit in the
2712 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2713
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2714 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2715 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2716 constant. TYPE must be a scalar or vector integer type. CST must be of
2717 scalar or vector floating point type. Both CST and TYPE must be scalars,
2718 or vectors of the same number of elements. If the value won't fit in the
2719 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2720
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2721 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2722 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2723 constant. TYPE must be a scalar or vector floating point type. CST must be
2724 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2725 vectors of the same number of elements. If the value won't fit in the
2726 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2727
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2729 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2730 constant. TYPE must be a scalar or vector floating point type. CST must be
2731 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2732 vectors of the same number of elements. If the value won't fit in the
2733 floating point type, the results are undefined.</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>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2736 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2737 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2738 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2739 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2740
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2741 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2742 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2743 type. CST must be of integer type. The CST value is zero extended,
2744 truncated, or unchanged to make it fit in a pointer size. This one is
2745 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2746
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2747 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2748 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2749 are the same as those for the <a href="#i_bitcast">bitcast
2750 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2751
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2753 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2754 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2755 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2756 instruction, the index list may have zero or more indexes, which are
2757 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2758
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2761
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2762 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2763 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2764
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2765 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2766 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2767
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2768 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2769 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2770 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2771
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2772 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2773 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2774 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2775
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2776 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2777 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2778 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2779
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2780 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2781 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2782 constants. The index list is interpreted in a similar manner as indices in
2783 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2784 index value must be specified.</dd>
2785
2786 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2787 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2788 constants. The index list is interpreted in a similar manner as indices in
2789 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2790 index value must be specified.</dd>
2791
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2792 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2793 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2794 be any of the <a href="#binaryops">binary</a>
2795 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2796 on operands are the same as those for the corresponding instruction
2797 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2798</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2799
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2801
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2802</div>
2803
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2804<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2805<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2806<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2807<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2808<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2809<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2810<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2811</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2812
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2813<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2816 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2817 a special value. This value represents the inline assembler as a string
2818 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2819 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2820 expression has side effects, and a flag indicating whether the function
2821 containing the asm needs to align its stack conservatively. An example
2822 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2823
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2824<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2825i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2826</pre>
2827
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2828<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2829 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2830 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2831
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2832<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2833%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]2834</pre>
2835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2836<p>Inline asms with side effects not visible in the constraint list must be
2837 marked as having side effects. This is done through the use of the
2838 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2839
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2840<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2841call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2842</pre>
2843
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2844<p>In some cases inline asms will contain code that will not work unless the
2845 stack is aligned in some way, such as calls or SSE instructions on x86,
2846 yet will not contain code that does that alignment within the asm.
2847 The compiler should make conservative assumptions about what the asm might
2848 contain and should generate its usual stack alignment code in the prologue
2849 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2850
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2851<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2852call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2853</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2854
2855<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2856 first.</p>
2857
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2858<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2859<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2860 documented here. Constraints on what can be done (e.g. duplication, moving,
2861 etc need to be documented). This is probably best done by reference to
2862 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2863 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2864
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2865<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2866<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2867 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2868</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2869
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2870<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2871
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2872<p>The call instructions that wrap inline asm nodes may have a
2873 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2874 integers. If present, the code generator will use the integer as the
2875 location cookie value when report errors through the <tt>LLVMContext</tt>
2876 error reporting mechanisms. This allows a front-end to correlate backend
2877 errors that occur with inline asm back to the source code that produced it.
2878 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2879
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2880<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2881call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2882...
2883!42 = !{ i32 1234567 }
2884</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2885
2886<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]2887 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2888 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]2889
2890</div>
2891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2892</div>
2893
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2894<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2895<h3>
2896 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2897</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2898
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2899<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2900
2901<p>LLVM IR allows metadata to be attached to instructions in the program that
2902 can convey extra information about the code to the optimizers and code
2903 generator. One example application of metadata is source-level debug
2904 information. There are two metadata primitives: strings and nodes. All
2905 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2906 preceding exclamation point ('<tt>!</tt>').</p>
2907
2908<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2909 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2910 "<tt>xx</tt>" is the two digit hex code. For example:
2911 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2912
2913<p>Metadata nodes are represented with notation similar to structure constants
2914 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2915 exclamation point). Metadata nodes can have any values as their operand. For
2916 example:</p>
2917
2918<div class="doc_code">
2919<pre>
2920!{ metadata !"test\00", i32 10}
2921</pre>
2922</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2923
2924<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2925 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2926 example:</p>
2927
2928<div class="doc_code">
2929<pre>
2930!foo = metadata !{!4, !3}
2931</pre>
2932</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2933
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2934<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2935 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2936
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2937<div class="doc_code">
2938<pre>
2939call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2940</pre>
2941</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2942
2943<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2944 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2945 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2946
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2947<div class="doc_code">
2948<pre>
2949%indvar.next = add i64 %indvar, 1, !dbg !21
2950</pre>
2951</div>
2952
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2953<p>More information about specific metadata nodes recognized by the optimizers
2954 and code generator is found below.</p>
2955
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2956<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2957<h4>
2958 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2959</h4>
2960
2961<div>
2962
2963<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2964 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2965 a type system of a higher level language. This can be used to implement
2966 typical C/C++ TBAA, but it can also be used to implement custom alias
2967 analysis behavior for other languages.</p>
2968
2969<p>The current metadata format is very simple. TBAA metadata nodes have up to
2970 three fields, e.g.:</p>
2971
2972<div class="doc_code">
2973<pre>
2974!0 = metadata !{ metadata !"an example type tree" }
2975!1 = metadata !{ metadata !"int", metadata !0 }
2976!2 = metadata !{ metadata !"float", metadata !0 }
2977!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2978</pre>
2979</div>
2980
2981<p>The first field is an identity field. It can be any value, usually
2982 a metadata string, which uniquely identifies the type. The most important
2983 name in the tree is the name of the root node. Two trees with
2984 different root node names are entirely disjoint, even if they
2985 have leaves with common names.</p>
2986
2987<p>The second field identifies the type's parent node in the tree, or
2988 is null or omitted for a root node. A type is considered to alias
2989 all of its descendants and all of its ancestors in the tree. Also,
2990 a type is considered to alias all types in other trees, so that
2991 bitcode produced from multiple front-ends is handled conservatively.</p>
2992
2993<p>If the third field is present, it's an integer which if equal to 1
2994 indicates that the type is "constant" (meaning
2995 <tt>pointsToConstantMemory</tt> should return true; see
2996 <a href="AliasAnalysis.html#OtherItfs">other useful
2997 <tt>AliasAnalysis</tt> methods</a>).</p>
2998
2999</div>
3000
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]3001<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3002<h4>
3003 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
3004</h4>
3005
3006<div>
3007
3008<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
3009 point type. It expresses the maximum relative error of the result of
3010 that instruction, in ULPs. ULP is defined as follows:</p>
3011
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3012<blockquote>
3013
3014<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3015 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3016 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3017 distance between the two non-equal finite floating-point numbers nearest
3018 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3019
3020</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3021
3022<p>The maximum relative error may be any rational number. The metadata node
3023 shall consist of a pair of unsigned integers respectively representing
3024 the numerator and denominator. For example, 2.5 ULP:</p>
3025
3026<div class="doc_code">
3027<pre>
3028!0 = metadata !{ i32 5, i32 2 }
3029</pre>
3030</div>
3031
Rafael Espindola39dd3282012-03-24 00:14:51 +0000[diff] [blame]3032<!-- _______________________________________________________________________ -->
3033<h4>
3034 <a name="range">'<tt>range</tt>' Metadata</a>
3035</h4>
3036
3037<div>
3038<p><tt>range</tt> metadata may be attached only to loads of integer types. It
3039 expresses the possible ranges the loaded value is in. The ranges are
3040 represented with a flattened list of integers. The loaded value is known to
3041 be in the union of the ranges defined by each consecutive pair. Each pair
3042 has the following properties:</p>
3043<ul>
3044 <li>The type must match the type loaded by the instruction.</li>
3045 <li>The pair <tt>a,b</tt> represents the range <tt>[a,b)</tt>.</li>
3046 <li>Both <tt>a</tt> and <tt>b</tt> are constants.</li>
3047 <li>The range is allowed to wrap.</li>
3048 <li>The range should not represent the full or empty set. That is,
3049 <tt>a!=b</tt>. </li>
3050</ul>
3051
3052<p>Examples:</p>
3053<div class="doc_code">
3054<pre>
3055 %a = load i8* %x, align 1, !range !0 ; Can only be 0 or 1
3056 %b = load i8* %y, align 1, !range !1 ; Can only be 255 (-1), 0 or 1
3057 %c = load i8* %z, align 1, !range !2 ; Can only be 0, 1, 3, 4 or 5
3058...
3059!0 = metadata !{ i8 0, i8 2 }
3060!1 = metadata !{ i8 255, i8 2 }
3061!2 = metadata !{ i8 0, i8 2, i8 3, i8 6 }
3062</pre>
3063</div>
3064</div>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3065</div>
3066
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3067</div>
3068
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3069</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3070
3071<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3072<h2>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3073 <a name="module_flags">Module Flags Metadata</a>
3074</h2>
3075<!-- *********************************************************************** -->
3076
3077<div>
3078
3079<p>Information about the module as a whole is difficult to convey to LLVM's
3080 subsystems. The LLVM IR isn't sufficient to transmit this
3081 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3082 facilitate this. These flags are in the form of key / value pairs &mdash;
3083 much like a dictionary &mdash; making it easy for any subsystem who cares
3084 about a flag to look it up.</p>
3085
3086<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3087 triplets. Each triplet has the following form:</p>
3088
3089<ul>
3090 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3091 when two (or more) modules are merged together, and it encounters two (or
3092 more) metadata with the same ID. The supported behaviors are described
3093 below.</li>
3094
3095 <li>The second element is a metadata string that is a unique ID for the
3096 metadata. How each ID is interpreted is documented below.</li>
3097
3098 <li>The third element is the value of the flag.</li>
3099</ul>
3100
3101<p>When two (or more) modules are merged together, the resulting
3102 <tt>llvm.module.flags</tt> metadata is the union of the
3103 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3104 with the <i>Override</i> behavior, which may override another flag's value
3105 (see below).</p>
3106
3107<p>The following behaviors are supported:</p>
3108
3109<table border="1" cellspacing="0" cellpadding="4">
3110 <tbody>
3111 <tr>
3112 <th>Value</th>
3113 <th>Behavior</th>
3114 </tr>
3115 <tr>
3116 <td>1</td>
3117 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3118 <dl>
3119 <dt><b>Error</b></dt>
3120 <dd>Emits an error if two values disagree. It is an error to have an ID
3121 with both an Error and a Warning behavior.</dd>
3122 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3123 </td>
3124 </tr>
3125 <tr>
3126 <td>2</td>
3127 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3128 <dl>
3129 <dt><b>Warning</b></dt>
3130 <dd>Emits a warning if two values disagree.</dd>
3131 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3132 </td>
3133 </tr>
3134 <tr>
3135 <td>3</td>
3136 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3137 <dl>
3138 <dt><b>Require</b></dt>
3139 <dd>Emits an error when the specified value is not present or doesn't
3140 have the specified value. It is an error for two (or more)
3141 <tt>llvm.module.flags</tt> with the same ID to have the Require
3142 behavior but different values. There may be multiple Require flags
3143 per ID.</dd>
3144 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3145 </td>
3146 </tr>
3147 <tr>
3148 <td>4</td>
3149 <td align="left">
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3150 <dl>
3151 <dt><b>Override</b></dt>
3152 <dd>Uses the specified value if the two values disagree. It is an
3153 error for two (or more) <tt>llvm.module.flags</tt> with the same
3154 ID to have the Override behavior but different values.</dd>
3155 </dl>
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3156 </td>
3157 </tr>
3158 </tbody>
3159</table>
3160
3161<p>An example of module flags:</p>
3162
3163<pre class="doc_code">
3164!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3165!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3166!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3167!3 = metadata !{ i32 3, metadata !"qux",
3168 metadata !{
3169 metadata !"foo", i32 1
3170 }
3171}
3172!llvm.module.flags = !{ !0, !1, !2, !3 }
3173</pre>
3174
3175<ul>
3176 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3177 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3178 error if their values are not equal.</p></li>
3179
3180 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3181 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3182 value '37' if their values are not equal.</p></li>
3183
3184 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3185 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3186 warning if their values are not equal.</p></li>
3187
3188 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3189
3190<pre class="doc_code">
3191metadata !{ metadata !"foo", i32 1 }
3192</pre>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3193
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3194 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3195 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3196 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3197 the same value or an error will be issued.</p></li>
3198</ul>
3199
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3200
3201<!-- ======================================================================= -->
3202<h3>
3203<a name="objc_gc_flags">Objective-C Garbage Collection Module Flags Metadata</a>
3204</h3>
3205
3206<div>
3207
3208<p>On the Mach-O platform, Objective-C stores metadata about garbage collection
3209 in a special section called "image info". The metadata consists of a version
3210 number and a bitmask specifying what types of garbage collection are
3211 supported (if any) by the file. If two or more modules are linked together
3212 their garbage collection metadata needs to be merged rather than appended
3213 together.</p>
3214
3215<p>The Objective-C garbage collection module flags metadata consists of the
3216 following key-value pairs:</p>
3217
3218<table border="1" cellspacing="0" cellpadding="4">
Bill Wendlingb3ef2232012-03-06 09:23:25 +0000[diff] [blame]3219 <col width="30%">
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3220 <tbody>
3221 <tr>
Bill Wendlinga0edecf2012-03-06 09:17:04 +0000[diff] [blame]3222 <th>Key</th>
Bill Wendlingf7b367c2012-02-16 01:10:50 +0000[diff] [blame]3223 <th>Value</th>
3224 </tr>
3225 <tr>
3226 <td><tt>Objective-C&nbsp;Version</tt></td>
3227 <td align="left"><b>[Required]</b> &mdash; The Objective-C ABI
3228 version. Valid values are 1 and 2.</td>
3229 </tr>
3230 <tr>
3231 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Version</tt></td>
3232 <td align="left"><b>[Required]</b> &mdash; The version of the image info
3233 section. Currently always 0.</td>
3234 </tr>
3235 <tr>
3236 <td><tt>Objective-C&nbsp;Image&nbsp;Info&nbsp;Section</tt></td>
3237 <td align="left"><b>[Required]</b> &mdash; The section to place the
3238 metadata. Valid values are <tt>"__OBJC, __image_info, regular"</tt> for
3239 Objective-C ABI version 1, and <tt>"__DATA,__objc_imageinfo, regular,
3240 no_dead_strip"</tt> for Objective-C ABI version 2.</td>
3241 </tr>
3242 <tr>
3243 <td><tt>Objective-C&nbsp;Garbage&nbsp;Collection</tt></td>
3244 <td align="left"><b>[Required]</b> &mdash; Specifies whether garbage
3245 collection is supported or not. Valid values are 0, for no garbage
3246 collection, and 2, for garbage collection supported.</td>
3247 </tr>
3248 <tr>
3249 <td><tt>Objective-C&nbsp;GC&nbsp;Only</tt></td>
3250 <td align="left"><b>[Optional]</b> &mdash; Specifies that only garbage
3251 collection is supported. If present, its value must be 6. This flag
3252 requires that the <tt>Objective-C Garbage Collection</tt> flag have the
3253 value 2.</td>
3254 </tr>
3255 </tbody>
3256</table>
3257
3258<p>Some important flag interactions:</p>
3259
3260<ul>
3261 <li>If a module with <tt>Objective-C Garbage Collection</tt> set to 0 is
3262 merged with a module with <tt>Objective-C Garbage Collection</tt> set to
3263 2, then the resulting module has the <tt>Objective-C Garbage
3264 Collection</tt> flag set to 0.</li>
3265
3266 <li>A module with <tt>Objective-C Garbage Collection</tt> set to 0 cannot be
3267 merged with a module with <tt>Objective-C GC Only</tt> set to 6.</li>
3268</ul>
3269
3270</div>
3271
Bill Wendlingb9d75a92012-02-11 11:59:36 +0000[diff] [blame]3272</div>
3273
3274<!-- *********************************************************************** -->
3275<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3276 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3277</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3278<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3279<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3280<p>LLVM has a number of "magic" global variables that contain data that affect
3281code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3282of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3283section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3284by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3285
3286<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3287<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3288<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3289</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3290
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3291<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3292
3293<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3294href="#linkage_appending">appending linkage</a>. This array contains a list of
3295pointers to global variables and functions which may optionally have a pointer
3296cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3297
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3298<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3299<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3300@X = global i8 4
3301@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3302
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3303@llvm.used = appending global [2 x i8*] [
3304 i8* @X,
3305 i8* bitcast (i32* @Y to i8*)
3306], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3307</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3308</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3309
3310<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]3311 compiler, assembler, and linker are required to treat the symbol as if there
3312 is a reference to the global that it cannot see. For example, if a variable
3313 has internal linkage and no references other than that from
3314 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3315 represent references from inline asms and other things the compiler cannot
3316 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3317
3318<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]3319 object file to prevent the assembler and linker from molesting the
3320 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3321
3322</div>
3323
3324<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3325<h3>
3326 <a name="intg_compiler_used">
3327 The '<tt>llvm.compiler.used</tt>' Global Variable
3328 </a>
3329</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3330
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3331<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3332
3333<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3334 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3335 touching the symbol. On targets that support it, this allows an intelligent
3336 linker to optimize references to the symbol without being impeded as it would
3337 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3338
3339<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]3340 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3341
3342</div>
3343
3344<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3345<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3346<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3347</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3348
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3349<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3350
3351<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3352<pre>
3353%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3354@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3355</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3356</div>
3357
3358<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3359 functions and associated priorities. The functions referenced by this array
3360 will be called in ascending order of priority (i.e. lowest first) when the
3361 module is loaded. The order of functions with the same priority is not
3362 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3363
3364</div>
3365
3366<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3367<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3368<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3369</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3370
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3371<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3372
3373<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3374<pre>
3375%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3376@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3377</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3378</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3379
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3380<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3381 and associated priorities. The functions referenced by this array will be
3382 called in descending order of priority (i.e. highest first) when the module
3383 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3384
3385</div>
3386
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3387</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3388
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3389<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3390<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3391<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3392
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3393<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3395<p>The LLVM instruction set consists of several different classifications of
3396 instructions: <a href="#terminators">terminator
3397 instructions</a>, <a href="#binaryops">binary instructions</a>,
3398 <a href="#bitwiseops">bitwise binary instructions</a>,
3399 <a href="#memoryops">memory instructions</a>, and
3400 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3402<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3403<h3>
3404 <a name="terminators">Terminator Instructions</a>
3405</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3406
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3407<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3408
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3410 in a program ends with a "Terminator" instruction, which indicates which
3411 block should be executed after the current block is finished. These
3412 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3413 control flow, not values (the one exception being the
3414 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3415
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3416<p>The terminator instructions are:
3417 '<a href="#i_ret"><tt>ret</tt></a>',
3418 '<a href="#i_br"><tt>br</tt></a>',
3419 '<a href="#i_switch"><tt>switch</tt></a>',
3420 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3421 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3422 '<a href="#i_resume"><tt>resume</tt></a>', and
3423 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3425<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3426<h4>
3427 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3428</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3429
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3430<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3432<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3433<pre>
3434 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]3435 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3436</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3438<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3440 a value) from a function back to the caller.</p>
3441
3442<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3443 value and then causes control flow, and one that just causes control flow to
3444 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3445
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3446<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3448 return value. The type of the return value must be a
3449 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3450
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3452 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3453 value or a return value with a type that does not match its type, or if it
3454 has a void return type and contains a '<tt>ret</tt>' instruction with a
3455 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3456
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3457<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3459 the calling function's context. If the caller is a
3460 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3461 instruction after the call. If the caller was an
3462 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3463 the beginning of the "normal" destination block. If the instruction returns
3464 a value, that value shall set the call or invoke instruction's return
3465 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3467<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3468<pre>
3469 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3470 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3471 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]3472</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3474</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3476<h4>
3477 <a name="i_br">'<tt>br</tt>' Instruction</a>
3478</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3479
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3480<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3481
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3482<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3484 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3485 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3486</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3487
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3488<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3490 different basic block in the current function. There are two forms of this
3491 instruction, corresponding to a conditional branch and an unconditional
3492 branch.</p>
3493
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3494<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3496 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3497 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3498 target.</p>
3499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3500<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3501<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3503 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3504 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3505
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3506<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3507<pre>
3508Test:
3509 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3510 br i1 %cond, label %IfEqual, label %IfUnequal
3511IfEqual:
3512 <a href="#i_ret">ret</a> i32 1
3513IfUnequal:
3514 <a href="#i_ret">ret</a> i32 0
3515</pre>
3516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3517</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3519<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3520<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3521 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3522</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3523
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3524<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3527<pre>
3528 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3529</pre>
3530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3531<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3532<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]3533 several different places. It is a generalization of the '<tt>br</tt>'
3534 instruction, allowing a branch to occur to one of many possible
3535 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3536
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3537<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3538<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3540 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3541 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3543<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3544<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3546 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3547 transferred to the corresponding destination; otherwise, control flow is
3548 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3549
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3550<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3551<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3552 <tt>switch</tt> instruction, this instruction may be code generated in
3553 different ways. For example, it could be generated as a series of chained
3554 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3555
3556<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3557<pre>
3558 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3559 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3560 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3561
3562 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3563 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3564
3565 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3566 switch i32 %val, label %otherwise [ i32 0, label %onzero
3567 i32 1, label %onone
3568 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3569</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3571</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3572
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3573
3574<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3575<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3576 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3577</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3578
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3579<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3580
3581<h5>Syntax:</h5>
3582<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3583 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]3584</pre>
3585
3586<h5>Overview:</h5>
3587
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3588<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3589 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3590 "<tt>address</tt>". Address must be derived from a <a
3591 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3592
3593<h5>Arguments:</h5>
3594
3595<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3596 rest of the arguments indicate the full set of possible destinations that the
3597 address may point to. Blocks are allowed to occur multiple times in the
3598 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3599
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3600<p>This destination list is required so that dataflow analysis has an accurate
3601 understanding of the CFG.</p>
3602
3603<h5>Semantics:</h5>
3604
3605<p>Control transfers to the block specified in the address argument. All
3606 possible destination blocks must be listed in the label list, otherwise this
3607 instruction has undefined behavior. This implies that jumps to labels
3608 defined in other functions have undefined behavior as well.</p>
3609
3610<h5>Implementation:</h5>
3611
3612<p>This is typically implemented with a jump through a register.</p>
3613
3614<h5>Example:</h5>
3615<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3616 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3617</pre>
3618
3619</div>
3620
3621
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3622<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3623<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3624 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3625</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3626
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3627<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3628
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3629<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3630<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3631 &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]3632 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3633</pre>
3634
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3635<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3636<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3637 function, with the possibility of control flow transfer to either the
3638 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3639 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3640 control flow will return to the "normal" label. If the callee (or any
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3641 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3642 instruction or other exception handling mechanism, control is interrupted and
3643 continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3644
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3645<p>The '<tt>exception</tt>' label is a
3646 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3647 exception. As such, '<tt>exception</tt>' label is required to have the
3648 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3649 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3650 happens, as its first non-PHI instruction. The restrictions on the
3651 "<tt>landingpad</tt>" instruction's tightly couples it to the
3652 "<tt>invoke</tt>" instruction, so that the important information contained
3653 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3654 code motion.</p>
3655
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3656<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3657<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3659<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3660 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3661 convention</a> the call should use. If none is specified, the call
3662 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3663
3664 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3666 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3667
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3668 <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]3669 function value being invoked. In most cases, this is a direct function
3670 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3671 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3672
3673 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3674 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3675
3676 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3677 signature argument types and parameter attributes. All arguments must be
3678 of <a href="#t_firstclass">first class</a> type. If the function
3679 signature indicates the function accepts a variable number of arguments,
3680 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3681
3682 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3684
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]3685 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3686 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3687 handling mechanism.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3688
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3689 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3691 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3692</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3693
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3694<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3695<p>This instruction is designed to operate as a standard
3696 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3697 primary difference is that it establishes an association with a label, which
3698 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3699
3700<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3701 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3702 exception. Additionally, this is important for implementation of
3703 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3705<p>For the purposes of the SSA form, the definition of the value returned by the
3706 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3707 block to the "normal" label. If the callee unwinds then no return value is
3708 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3709
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3710<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3711<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3712 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3713 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3714 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3715 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3716</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3717
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3718</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3719
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3720 <!-- _______________________________________________________________________ -->
3721
3722<h4>
3723 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3724</h4>
3725
3726<div>
3727
3728<h5>Syntax:</h5>
3729<pre>
3730 resume &lt;type&gt; &lt;value&gt;
3731</pre>
3732
3733<h5>Overview:</h5>
3734<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3735 successors.</p>
3736
3737<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3738<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3739 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3740 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3741
3742<h5>Semantics:</h5>
3743<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3744 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3745 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3746
3747<h5>Example:</h5>
3748<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3749 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3750</pre>
3751
3752</div>
3753
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3754<!-- _______________________________________________________________________ -->
3755
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3756<h4>
3757 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3758</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3759
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3760<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3761
3762<h5>Syntax:</h5>
3763<pre>
3764 unreachable
3765</pre>
3766
3767<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3768<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769 instruction is used to inform the optimizer that a particular portion of the
3770 code is not reachable. This can be used to indicate that the code after a
3771 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3772
3773<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3774<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3775
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3776</div>
3777
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3778</div>
3779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3780<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3781<h3>
3782 <a name="binaryops">Binary Operations</a>
3783</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3785<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786
3787<p>Binary operators are used to do most of the computation in a program. They
3788 require two operands of the same type, execute an operation on them, and
3789 produce a single value. The operands might represent multiple data, as is
3790 the case with the <a href="#t_vector">vector</a> data type. The result value
3791 has the same type as its operands.</p>
3792
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3793<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3795<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3796<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3797 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3798</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3800<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3801
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3802<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3803<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3804 &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]3805 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3806 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3807 &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]3808</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3809
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3810<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3811<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3813<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814<p>The two arguments to the '<tt>add</tt>' instruction must
3815 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3816 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3817
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3818<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3819<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3820
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3821<p>If the sum has unsigned overflow, the result returned is the mathematical
3822 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]3823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824<p>Because LLVM integers use a two's complement representation, this instruction
3825 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3826
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3827<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3828 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3829 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3830 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3831 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3833<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3834<pre>
3835 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3836</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3838</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3839
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3840<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3841<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3842 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3843</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3844
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3845<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3846
3847<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3848<pre>
3849 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3850</pre>
3851
3852<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3853<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3854
3855<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3856<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3858 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3859
3860<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3861<p>The value produced is the floating point sum of the two operands.</p>
3862
3863<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3864<pre>
3865 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3866</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3867
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3868</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3869
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3870<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3871<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3872 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3873</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3874
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3875<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3878<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3879 &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]3880 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3881 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3882 &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]3883</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3885<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3886<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3887 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3888
3889<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890 '<tt>neg</tt>' instruction present in most other intermediate
3891 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894<p>The two arguments to the '<tt>sub</tt>' instruction must
3895 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3896 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3898<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3899<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3900
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3901<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3902 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3903 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905<p>Because LLVM integers use a two's complement representation, this instruction
3906 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3907
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3908<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3909 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3910 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3911 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3912 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3914<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3915<pre>
3916 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3917 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3918</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3920</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3923<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3924 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3925</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3927<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3928
3929<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3930<pre>
3931 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3932</pre>
3933
3934<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3935<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3936 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3937
3938<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3939 '<tt>fneg</tt>' instruction present in most other intermediate
3940 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3941
3942<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3943<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3945 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3946
3947<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3948<p>The value produced is the floating point difference of the two operands.</p>
3949
3950<h5>Example:</h5>
3951<pre>
3952 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3953 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3954</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3956</div>
3957
3958<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3959<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3960 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3961</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3962
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3963<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3965<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3966<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3967 &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]3968 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3969 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3970 &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]3971</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3973<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3975
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3976<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977<p>The two arguments to the '<tt>mul</tt>' instruction must
3978 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3979 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3981<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3982<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3983
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3984<p>If the result of the multiplication has unsigned overflow, the result
3985 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3986 width of the result.</p>
3987
3988<p>Because LLVM integers use a two's complement representation, and the result
3989 is the same width as the operands, this instruction returns the correct
3990 result for both signed and unsigned integers. If a full product
3991 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3992 be sign-extended or zero-extended as appropriate to the width of the full
3993 product.</p>
3994
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3995<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3996 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3997 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3998 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3999 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4000
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4001<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002<pre>
4003 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4004</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4005
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4006</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4007
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4008<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4009<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4010 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4011</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4012
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4013<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4014
4015<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4016<pre>
4017 &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]4018</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4020<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4022
4023<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4024<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4025 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4026 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4027
4028<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4029<p>The value produced is the floating point product of the two operands.</p>
4030
4031<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032<pre>
4033 &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]4034</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4035
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]4036</div>
4037
4038<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4039<h4>
4040 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
4041</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4043<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4045<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4047 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4048 &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]4049</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4050
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4051<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4052<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4053
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4054<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4055<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4056 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4057 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4058
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4059<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4060<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4061
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4062<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
4064
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4065<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]4067<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4068 <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]4069 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
4070
4071
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4072<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073<pre>
4074 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4075</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4076
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4077</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4078
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4079<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4080<h4>
4081 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
4082</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4083
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4084<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4085
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4086<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4087<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4088 &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]4089 &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]4090</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4091
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4092<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4093<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4094
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4095<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4096<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4097 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4098 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4099
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4100<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4101<p>The value produced is the signed integer quotient of the two operands rounded
4102 towards zero.</p>
4103
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4104<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4105 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
4106
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4107<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4108 undefined behavior; this is a rare case, but can occur, for example, by doing
4109 a 32-bit division of -2147483648 by -1.</p>
4110
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]4111<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4112 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]4113 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]4114
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4115<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4116<pre>
4117 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4118</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4120</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4121
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4122<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4123<h4>
4124 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4125</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4126
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4127<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4129<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4130<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4131 &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]4132</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4134<h5>Overview:</h5>
4135<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4136
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4137<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4138<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4140 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4141
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4142<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]4143<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4144
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4145<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4146<pre>
4147 &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]4148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4150</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4151
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4152<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4153<h4>
4154 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4155</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4156
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4157<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4158
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4159<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4160<pre>
4161 &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]4162</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4164<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4166 division of its two arguments.</p>
4167
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4168<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4169<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4170 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4171 values. Both arguments must have identical types.</p>
4172
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4173<h5>Semantics:</h5>
4174<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4175 This instruction always performs an unsigned division to get the
4176 remainder.</p>
4177
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4178<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4180
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4181<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4183<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4184<pre>
4185 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4186</pre>
4187
4188</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4190<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4191<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4192 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4193</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4194
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4195<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4196
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4197<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4198<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4199 &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]4200</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4201
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4202<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4203<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4204 division of its two operands. This instruction can also take
4205 <a href="#t_vector">vector</a> versions of the values in which case the
4206 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]4207
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4208<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4209<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4210 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4211 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4212
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4213<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4214<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4215 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4216 <i>modulo</i> operator (where the result is either zero or has the same sign
4217 as the divisor, <tt>op2</tt>) of a value.
4218 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4220 Math Forum</a>. For a table of how this is implemented in various languages,
4221 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4222 Wikipedia: modulo operation</a>.</p>
4223
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4224<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4225 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4226
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4227<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4228 Overflow also leads to undefined behavior; this is a rare case, but can
4229 occur, for example, by taking the remainder of a 32-bit division of
4230 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4231 lets srem be implemented using instructions that return both the result of
4232 the division and the remainder.)</p>
4233
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4234<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4235<pre>
4236 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4237</pre>
4238
4239</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4241<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4242<h4>
4243 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4244</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4245
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4246<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4247
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4248<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249<pre>
4250 &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]4251</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4252
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4253<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4255 its two operands.</p>
4256
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4257<h5>Arguments:</h5>
4258<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4260 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4261
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4262<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4263<p>This instruction returns the <i>remainder</i> of a division. The remainder
4264 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4265
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4266<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4267<pre>
4268 &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]4269</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4271</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4272
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4273</div>
4274
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4275<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4276<h3>
4277 <a name="bitwiseops">Bitwise Binary Operations</a>
4278</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4279
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4280<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4281
4282<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4283 program. They are generally very efficient instructions and can commonly be
4284 strength reduced from other instructions. They require two operands of the
4285 same type, execute an operation on them, and produce a single value. The
4286 resulting value is the same type as its operands.</p>
4287
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4288<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4289<h4>
4290 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4291</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4293<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4295<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4297 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4298 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4299 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4300 &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]4301</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4302
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4303<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4305 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4306
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4307<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4309 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4310 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4311
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4312<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4314 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4315 is (statically or dynamically) negative or equal to or larger than the number
4316 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4317 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4318 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4319
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4320<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4321 <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]4322 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4323 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4324 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4325 they would if the shift were expressed as a mul instruction with the same
4326 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4327
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4328<h5>Example:</h5>
4329<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4330 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4331 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4332 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4333 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4334 &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]4335</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4336
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4337</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4339<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4340<h4>
4341 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4342</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4343
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4344<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4345
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4346<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4347<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4348 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4349 &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]4350</pre>
4351
4352<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4353<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4354 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4355
4356<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4357<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4359 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4360
4361<h5>Semantics:</h5>
4362<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4363 significant bits of the result will be filled with zero bits after the shift.
4364 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4365 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4366 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4367 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4368
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4369<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4370 <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]4371 shifted out are non-zero.</p>
4372
4373
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4374<h5>Example:</h5>
4375<pre>
4376 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4377 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4378 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4379 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4380 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4381 &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]4382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4384</div>
4385
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4386<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4387<h4>
4388 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4389</h4>
4390
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4391<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4392
4393<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4394<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4395 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4396 &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]4397</pre>
4398
4399<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4401 operand shifted to the right a specified number of bits with sign
4402 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4403
4404<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4405<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4406 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4407 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4408
4409<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410<p>This instruction always performs an arithmetic shift right operation, The
4411 most significant bits of the result will be filled with the sign bit
4412 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4413 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4414 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4415 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4416
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4417<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4418 <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]4419 shifted out are non-zero.</p>
4420
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4421<h5>Example:</h5>
4422<pre>
4423 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4424 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4425 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4426 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4427 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4428 &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]4429</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4430
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4431</div>
4432
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4433<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4434<h4>
4435 <a name="i_and">'<tt>and</tt>' Instruction</a>
4436</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4437
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4438<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4439
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4440<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4441<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4442 &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]4443</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4445<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4446<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4447 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4448
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4449<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4450<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4451 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4452 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4453
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4454<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4455<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4457<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4458 <tbody>
4459 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4460 <th>In0</th>
4461 <th>In1</th>
4462 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4463 </tr>
4464 <tr>
4465 <td>0</td>
4466 <td>0</td>
4467 <td>0</td>
4468 </tr>
4469 <tr>
4470 <td>0</td>
4471 <td>1</td>
4472 <td>0</td>
4473 </tr>
4474 <tr>
4475 <td>1</td>
4476 <td>0</td>
4477 <td>0</td>
4478 </tr>
4479 <tr>
4480 <td>1</td>
4481 <td>1</td>
4482 <td>1</td>
4483 </tr>
4484 </tbody>
4485</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4486
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4487<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4488<pre>
4489 &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]4490 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4491 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4492</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4493</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4494<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4495<h4>
4496 <a name="i_or">'<tt>or</tt>' Instruction</a>
4497</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4498
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4499<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500
4501<h5>Syntax:</h5>
4502<pre>
4503 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4504</pre>
4505
4506<h5>Overview:</h5>
4507<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4508 two operands.</p>
4509
4510<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4511<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4512 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4513 values. Both arguments must have identical types.</p>
4514
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4515<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4516<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4517
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4518<table border="1" cellspacing="0" cellpadding="4">
4519 <tbody>
4520 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4521 <th>In0</th>
4522 <th>In1</th>
4523 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4524 </tr>
4525 <tr>
4526 <td>0</td>
4527 <td>0</td>
4528 <td>0</td>
4529 </tr>
4530 <tr>
4531 <td>0</td>
4532 <td>1</td>
4533 <td>1</td>
4534 </tr>
4535 <tr>
4536 <td>1</td>
4537 <td>0</td>
4538 <td>1</td>
4539 </tr>
4540 <tr>
4541 <td>1</td>
4542 <td>1</td>
4543 <td>1</td>
4544 </tr>
4545 </tbody>
4546</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4547
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4548<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4549<pre>
4550 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4551 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4552 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4553</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4554
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4555</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4556
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4557<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4558<h4>
4559 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4560</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4561
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4562<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4563
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4564<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4565<pre>
4566 &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]4567</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4569<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4570<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4571 its two operands. The <tt>xor</tt> is used to implement the "one's
4572 complement" operation, which is the "~" operator in C.</p>
4573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4574<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4575<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4576 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4577 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4578
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4579<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4580<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4581
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4582<table border="1" cellspacing="0" cellpadding="4">
4583 <tbody>
4584 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4585 <th>In0</th>
4586 <th>In1</th>
4587 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4588 </tr>
4589 <tr>
4590 <td>0</td>
4591 <td>0</td>
4592 <td>0</td>
4593 </tr>
4594 <tr>
4595 <td>0</td>
4596 <td>1</td>
4597 <td>1</td>
4598 </tr>
4599 <tr>
4600 <td>1</td>
4601 <td>0</td>
4602 <td>1</td>
4603 </tr>
4604 <tr>
4605 <td>1</td>
4606 <td>1</td>
4607 <td>0</td>
4608 </tr>
4609 </tbody>
4610</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4612<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613<pre>
4614 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4615 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4616 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4617 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4618</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4619
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4620</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4621
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4622</div>
4623
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4624<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4625<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4626 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4627</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4628
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4629<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4630
4631<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4632 target-independent manner. These instructions cover the element-access and
4633 vector-specific operations needed to process vectors effectively. While LLVM
4634 does directly support these vector operations, many sophisticated algorithms
4635 will want to use target-specific intrinsics to take full advantage of a
4636 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4637
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4638<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4639<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4640 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4641</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4642
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4643<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4644
4645<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4646<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4647 &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]4648</pre>
4649
4650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4652 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4653
4654
4655<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4657 of <a href="#t_vector">vector</a> type. The second operand is an index
4658 indicating the position from which to extract the element. The index may be
4659 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4660
4661<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662<p>The result is a scalar of the same type as the element type of
4663 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4664 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4665 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4666
4667<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4668<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4669 &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]4670</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4671
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4673
4674<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4675<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4676 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4677</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4678
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4679<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4680
4681<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4682<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4683 &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]4684</pre>
4685
4686<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4688 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4689
4690<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4692 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4693 whose type must equal the element type of the first operand. The third
4694 operand is an index indicating the position at which to insert the value.
4695 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4696
4697<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4698<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4699 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4700 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4701 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4702
4703<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4704<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4705 &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]4706</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4708</div>
4709
4710<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4711<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4712 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4713</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4714
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4715<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4716
4717<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4718<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4719 &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]4720</pre>
4721
4722<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4724 from two input vectors, returning a vector with the same element type as the
4725 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4726
4727<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4728<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4729 with types that match each other. The third argument is a shuffle mask whose
4730 element type is always 'i32'. The result of the instruction is a vector
4731 whose length is the same as the shuffle mask and whose element type is the
4732 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4733
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734<p>The shuffle mask operand is required to be a constant vector with either
4735 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4736
4737<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4738<p>The elements of the two input vectors are numbered from left to right across
4739 both of the vectors. The shuffle mask operand specifies, for each element of
4740 the result vector, which element of the two input vectors the result element
4741 gets. The element selector may be undef (meaning "don't care") and the
4742 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4743
4744<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4745<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4746 &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]4747 &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]4748 &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]4749 &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]4750 &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]4751 &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]4752 &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]4753 &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]4754</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4755
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4756</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4757
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4758</div>
4759
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4760<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4761<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4762 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4763</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4764
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4765<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4766
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4767<p>LLVM supports several instructions for working with
4768 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4769
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4770<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4771<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4772 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4773</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4774
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4775<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4776
4777<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4778<pre>
4779 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4780</pre>
4781
4782<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4783<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4784 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +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>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4788 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4789 <a href="#t_array">array</a> type. The operands are constant indices to
4790 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4791 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4792 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4793 <ul>
4794 <li>Since the value being indexed is not a pointer, the first index is
4795 omitted and assumed to be zero.</li>
4796 <li>At least one index must be specified.</li>
4797 <li>Not only struct indices but also array indices must be in
4798 bounds.</li>
4799 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4800
4801<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802<p>The result is the value at the position in the aggregate specified by the
4803 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4804
4805<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4806<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4807 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4808</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4809
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4810</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4811
4812<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4813<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4814 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4815</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4816
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4817<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4818
4819<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4820<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4821 &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]4822</pre>
4823
4824<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4825<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4826 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4827
4828<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4829<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4830 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4831 <a href="#t_array">array</a> type. The second operand is a first-class
4832 value to insert. The following operands are constant indices indicating
4833 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]4834 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4835 value to insert must have the same type as the value identified by the
4836 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4837
4838<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4839<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4840 that of <tt>val</tt> except that the value at the position specified by the
4841 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4842
4843<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4844<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4845 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4846 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4847 %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]4848</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4849
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4850</div>
4851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4852</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4853
4854<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4855<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4856 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4857</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4858
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4859<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4860
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4861<p>A key design point of an SSA-based representation is how it represents
4862 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4863 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4864 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4865
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4866<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4867<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4868 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4869</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4870
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4871<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4872
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4873<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4874<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4875 &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]4876</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4878<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4879<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4880 currently executing function, to be automatically released when this function
4881 returns to its caller. The object is always allocated in the generic address
4882 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4884<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4885<p>The '<tt>alloca</tt>' instruction
4886 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4887 runtime stack, returning a pointer of the appropriate type to the program.
4888 If "NumElements" is specified, it is the number of elements allocated,
4889 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4890 specified, the value result of the allocation is guaranteed to be aligned to
4891 at least that boundary. If not specified, or if zero, the target can choose
4892 to align the allocation on any convenient boundary compatible with the
4893 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4894
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4895<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4896
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4897<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4898<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4900 memory is automatically released when the function returns. The
4901 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4902 variables that must have an address available. When the function returns
4903 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling7b9e5392012-02-06 21:57:33 +0000[diff] [blame]4904 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4905 reclaimed. Allocating zero bytes is legal, but the result is undefined.
4906 The order in which memory is allocated (ie., which way the stack grows) is
Nick Lewycky75d05e62012-03-18 09:35:50 +0000[diff] [blame]4907 not specified.</p>
Nick Lewycky84a1d232012-02-29 08:26:44 +0000[diff] [blame]4908
4909<p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4911<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4912<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4913 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4914 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4915 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4916 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4917</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4919</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4921<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4922<h4>
4923 <a name="i_load">'<tt>load</tt>' Instruction</a>
4924</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4925
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4926<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4927
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4928<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4929<pre>
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4930 &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]4931 &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]4932 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4933</pre>
4934
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4935<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4936<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4938<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4939<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4940 from which to load. The pointer must point to
4941 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4942 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4943 number or order of execution of this <tt>load</tt> with other <a
4944 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4945
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4946<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4947 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4948 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4949 not valid on <code>load</code> instructions. Atomic loads produce <a
4950 href="#memorymodel">defined</a> results when they may see multiple atomic
4951 stores. The type of the pointee must be an integer type whose bit width
4952 is a power of two greater than or equal to eight and less than or equal
4953 to a target-specific size limit. <code>align</code> must be explicitly
4954 specified on atomic loads, and the load has undefined behavior if the
4955 alignment is not set to a value which is at least the size in bytes of
4956 the pointee. <code>!nontemporal</code> does not have any defined semantics
4957 for atomic loads.</p>
4958
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4959<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960 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]4961 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4962 alignment for the target. It is the responsibility of the code emitter to
4963 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4964 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4965 produce less efficient code. An alignment of 1 is always safe.</p>
4966
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4967<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4968 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4969 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4970 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4971 and code generator that this load is not expected to be reused in the cache.
4972 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4973 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4974
Pete Cooperf95acc62012-02-10 18:13:54 +0000[diff] [blame]4975<p>The optional <tt>!invariant.load</tt> metadata must reference a single
4976 metatadata name &lt;index&gt; corresponding to a metadata node with no
4977 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
4978 instruction tells the optimizer and code generator that this load address
4979 points to memory which does not change value during program execution.
4980 The optimizer may then move this load around, for example, by hoisting it
4981 out of loops using loop invariant code motion.</p>
4982
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4983<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984<p>The location of memory pointed to is loaded. If the value being loaded is of
4985 scalar type then the number of bytes read does not exceed the minimum number
4986 of bytes needed to hold all bits of the type. For example, loading an
4987 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4988 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4989 is undefined if the value was not originally written using a store of the
4990 same type.</p>
4991
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4992<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4993<pre>
4994 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4995 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4996 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4997</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4998
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4999</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5000
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5001<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5002<h4>
5003 <a name="i_store">'<tt>store</tt>' Instruction</a>
5004</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5005
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5006<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5007
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5008<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5009<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5010 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>
5011 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]5012</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5014<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5015<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5017<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5018<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
5019 and an address at which to store it. The type of the
5020 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
5021 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]5022 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
5023 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
5024 order of execution of this <tt>store</tt> with other <a
5025 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5026
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]5027<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
5028 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
5029 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
5030 valid on <code>store</code> instructions. Atomic loads produce <a
5031 href="#memorymodel">defined</a> results when they may see multiple atomic
5032 stores. The type of the pointee must be an integer type whose bit width
5033 is a power of two greater than or equal to eight and less than or equal
5034 to a target-specific size limit. <code>align</code> must be explicitly
5035 specified on atomic stores, and the store has undefined behavior if the
5036 alignment is not set to a value which is at least the size in bytes of
5037 the pointee. <code>!nontemporal</code> does not have any defined semantics
5038 for atomic stores.</p>
5039
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040<p>The optional constant "align" argument specifies the alignment of the
5041 operation (that is, the alignment of the memory address). A value of 0 or an
5042 omitted "align" argument means that the operation has the preferential
5043 alignment for the target. It is the responsibility of the code emitter to
5044 ensure that the alignment information is correct. Overestimating the
5045 alignment results in an undefined behavior. Underestimating the alignment may
5046 produce less efficient code. An alignment of 1 is always safe.</p>
5047
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5048<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5049 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5050 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5051 instruction tells the optimizer and code generator that this load is
5052 not expected to be reused in the cache. The code generator may
5053 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5054 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]5055
5056
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5057<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5058<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
5059 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
5060 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
5061 does not exceed the minimum number of bytes needed to hold all bits of the
5062 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
5063 writing a value of a type like <tt>i20</tt> with a size that is not an
5064 integral number of bytes, it is unspecified what happens to the extra bits
5065 that do not belong to the type, but they will typically be overwritten.</p>
5066
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5067<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068<pre>
5069 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]5070 store i32 3, i32* %ptr <i>; yields {void}</i>
5071 %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]5072</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5074</div>
5075
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]5076<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5077<h4>
5078<a name="i_fence">'<tt>fence</tt>' Instruction</a>
5079</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5080
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5081<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5082
5083<h5>Syntax:</h5>
5084<pre>
5085 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
5086</pre>
5087
5088<h5>Overview:</h5>
5089<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
5090between operations.</p>
5091
5092<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
5093href="#ordering">ordering</a> argument which defines what
5094<i>synchronizes-with</i> edges they add. They can only be given
5095<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
5096<code>seq_cst</code> orderings.</p>
5097
5098<h5>Semantics:</h5>
5099<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
5100semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
5101<code>acquire</code> ordering semantics if and only if there exist atomic
5102operations <var>X</var> and <var>Y</var>, both operating on some atomic object
5103<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
5104<var>X</var> modifies <var>M</var> (either directly or through some side effect
5105of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
5106<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
5107<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
5108than an explicit <code>fence</code>, one (but not both) of the atomic operations
5109<var>X</var> or <var>Y</var> might provide a <code>release</code> or
5110<code>acquire</code> (resp.) ordering constraint and still
5111<i>synchronize-with</i> the explicit <code>fence</code> and establish the
5112<i>happens-before</i> edge.</p>
5113
5114<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
5115having both <code>acquire</code> and <code>release</code> semantics specified
5116above, participates in the global program order of other <code>seq_cst</code>
5117operations and/or fences.</p>
5118
5119<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5120specifies that the fence only synchronizes with other fences in the same
5121thread. (This is useful for interacting with signal handlers.)</p>
5122
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]5123<h5>Example:</h5>
5124<pre>
5125 fence acquire <i>; yields {void}</i>
5126 fence singlethread seq_cst <i>; yields {void}</i>
5127</pre>
5128
5129</div>
5130
5131<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5132<h4>
5133<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5134</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5135
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5136<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5137
5138<h5>Syntax:</h5>
5139<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5140 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]5141</pre>
5142
5143<h5>Overview:</h5>
5144<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5145It loads a value in memory and compares it to a given value. If they are
5146equal, it stores a new value into the memory.</p>
5147
5148<h5>Arguments:</h5>
5149<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5150address to operate on, a value to compare to the value currently be at that
5151address, and a new value to place at that address if the compared values are
5152equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5153bit width is a power of two greater than or equal to eight and less than
5154or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5155'<var>&lt;new&gt;</var>' must have the same type, and the type of
5156'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5157<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5158optimizer is not allowed to modify the number or order of execution
5159of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5160operations</a>.</p>
5161
5162<!-- FIXME: Extend allowed types. -->
5163
5164<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5165<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5166
5167<p>The optional "<code>singlethread</code>" argument declares that the
5168<code>cmpxchg</code> is only atomic with respect to code (usually signal
5169handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5170cmpxchg is atomic with respect to all other code in the system.</p>
5171
5172<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5173the size in memory of the operand.
5174
5175<h5>Semantics:</h5>
5176<p>The contents of memory at the location specified by the
5177'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5178'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5179'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5180is returned.
5181
5182<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5183purpose of identifying <a href="#release_sequence">release sequences</a>. A
5184failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5185parameter determined by dropping any <code>release</code> part of the
5186<code>cmpxchg</code>'s ordering.</p>
5187
5188<!--
5189FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5190optimization work on ARM.)
5191
5192FIXME: Is a weaker ordering constraint on failure helpful in practice?
5193-->
5194
5195<h5>Example:</h5>
5196<pre>
5197entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5198 %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]5199 <a href="#i_br">br</a> label %loop
5200
5201loop:
5202 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5203 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]5204 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5205 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5206 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5207
5208done:
5209 ...
5210</pre>
5211
5212</div>
5213
5214<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5215<h4>
5216<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5217</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5218
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]5219<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5220
5221<h5>Syntax:</h5>
5222<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5223 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]5224</pre>
5225
5226<h5>Overview:</h5>
5227<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5228
5229<h5>Arguments:</h5>
5230<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5231operation to apply, an address whose value to modify, an argument to the
5232operation. The operation must be one of the following keywords:</p>
5233<ul>
5234 <li>xchg</li>
5235 <li>add</li>
5236 <li>sub</li>
5237 <li>and</li>
5238 <li>nand</li>
5239 <li>or</li>
5240 <li>xor</li>
5241 <li>max</li>
5242 <li>min</li>
5243 <li>umax</li>
5244 <li>umin</li>
5245</ul>
5246
5247<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5248bit width is a power of two greater than or equal to eight and less than
5249or equal to a target-specific size limit. The type of the
5250'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5251If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5252optimizer is not allowed to modify the number or order of execution of this
5253<code>atomicrmw</code> with other <a href="#volatile">volatile
5254 operations</a>.</p>
5255
5256<!-- FIXME: Extend allowed types. -->
5257
5258<h5>Semantics:</h5>
5259<p>The contents of memory at the location specified by the
5260'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5261back. The original value at the location is returned. The modification is
5262specified by the <var>operation</var> argument:</p>
5263
5264<ul>
5265 <li>xchg: <code>*ptr = val</code></li>
5266 <li>add: <code>*ptr = *ptr + val</code></li>
5267 <li>sub: <code>*ptr = *ptr - val</code></li>
5268 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5269 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5270 <li>or: <code>*ptr = *ptr | val</code></li>
5271 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5272 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5273 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5274 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5275 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5276</ul>
5277
5278<h5>Example:</h5>
5279<pre>
5280 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5281</pre>
5282
5283</div>
5284
5285<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5286<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5287 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5288</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5289
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5290<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5291
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5292<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5293<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5294 &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]5295 &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]5296 &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]5297</pre>
5298
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5299<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5300<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5301 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5302 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5303
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5304<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5305<p>The first argument is always a pointer or a vector of pointers,
5306 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5307 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5308 elements of the aggregate object are indexed. The interpretation of each
5309 index is dependent on the type being indexed into. The first index always
5310 indexes the pointer value given as the first argument, the second index
5311 indexes a value of the type pointed to (not necessarily the value directly
5312 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5313 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5314 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5315 can never be pointers, since that would require loading the pointer before
5316 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5317
5318<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]5319 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5320 integer <b>constants</b> are allowed. When indexing into an array, pointer
5321 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]5322 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5323
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5324<p>For example, let's consider a C code fragment and how it gets compiled to
5325 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5326
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5327<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5328struct RT {
5329 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5330 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5331 char C;
5332};
5333struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5334 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5335 double Y;
5336 struct RT Z;
5337};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5338
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5339int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5340 return &amp;s[1].Z.B[5][13];
5341}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5342</pre>
5343
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5344<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5345
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5346<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5347%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5348%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5349
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5350define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5351entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5352 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5353 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5354}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5355</pre>
5356
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5357<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5358<p>In the example above, the first index is indexing into the
5359 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5360 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5361 structure. The second index indexes into the third element of the structure,
5362 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5363 type, another structure. The third index indexes into the second element of
5364 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5365 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5366 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5367 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5369<p>Note that it is perfectly legal to index partially through a structure,
5370 returning a pointer to an inner element. Because of this, the LLVM code for
5371 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5372
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5373<pre class="doc_code">
5374define i32* @foo(%struct.ST* %s) {
5375 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5376 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5377 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5378 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5379 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5380 ret i32* %t5
5381}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5382</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5383
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5384<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5385 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5386 base pointer is not an <i>in bounds</i> address of an allocated object,
5387 or if any of the addresses that would be formed by successive addition of
5388 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5389 precise signed arithmetic are not an <i>in bounds</i> address of that
5390 allocated object. The <i>in bounds</i> addresses for an allocated object
5391 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5392 byte past the end.
5393 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5394 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5395
5396<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]5397 the base address with silently-wrapping two's complement arithmetic. If the
5398 offsets have a different width from the pointer, they are sign-extended or
5399 truncated to the width of the pointer. The result value of the
5400 <tt>getelementptr</tt> may be outside the object pointed to by the base
5401 pointer. The result value may not necessarily be used to access memory
5402 though, even if it happens to point into allocated storage. See the
5403 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5404 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5405
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5406<p>The getelementptr instruction is often confusing. For some more insight into
5407 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5408
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5409<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5410<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5411 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5412 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5413 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5414 %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]5415 <i>; yields i8*:eptr</i>
5416 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5417 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5418 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5419</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5420
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5421<p>In cases where the pointer argument is a vector of pointers, only a
5422 single index may be used, and the number of vector elements has to be
5423 the same. For example: </p>
5424<pre class="doc_code">
5425 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5426</pre>
5427
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5428</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5429
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5430</div>
5431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5432<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5433<h3>
5434 <a name="convertops">Conversion Operations</a>
5435</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5436
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5437<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5438
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5439<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5440 which all take a single operand and a type. They perform various bit
5441 conversions on the operand.</p>
5442
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5443<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5444<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5445 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5446</h4>
5447
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5448<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5449
5450<h5>Syntax:</h5>
5451<pre>
5452 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5453</pre>
5454
5455<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5456<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5457 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5458
5459<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5460<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5461 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5462 of the same number of integers.
5463 The bit size of the <tt>value</tt> must be larger than
5464 the bit size of the destination type, <tt>ty2</tt>.
5465 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5466
5467<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5468<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5469 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5470 source size must be larger than the destination size, <tt>trunc</tt> cannot
5471 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5472
5473<h5>Example:</h5>
5474<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5475 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5476 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5477 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5478 %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]5479</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5481</div>
5482
5483<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5484<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5485 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5486</h4>
5487
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5488<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5489
5490<h5>Syntax:</h5>
5491<pre>
5492 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5493</pre>
5494
5495<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5496<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5497 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5498
5499
5500<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5501<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5502 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5503 of the same number of integers.
5504 The bit size of the <tt>value</tt> must be smaller than
5505 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5506 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5507
5508<h5>Semantics:</h5>
5509<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]5510 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5511
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5512<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]5513
5514<h5>Example:</h5>
5515<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5516 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5517 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5518 %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]5519</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5520
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5521</div>
5522
5523<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5524<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5525 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5526</h4>
5527
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5528<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5529
5530<h5>Syntax:</h5>
5531<pre>
5532 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5533</pre>
5534
5535<h5>Overview:</h5>
5536<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5537
5538<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5539<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5540 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5541 of the same number of integers.
5542 The bit size of the <tt>value</tt> must be smaller than
5543 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5544 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5545
5546<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5547<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5548 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5549 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5550
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5551<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]5552
5553<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5554<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5555 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5556 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5557 %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]5558</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5559
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5560</div>
5561
5562<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5563<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5564 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5565</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5566
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5567<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5568
5569<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5570<pre>
5571 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5572</pre>
5573
5574<h5>Overview:</h5>
5575<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5576 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5577
5578<h5>Arguments:</h5>
5579<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5580 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5581 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]5582 <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]5583 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5584
5585<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5586<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5587 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5588 <a href="#t_floating">floating point</a> type. If the value cannot fit
5589 within the destination type, <tt>ty2</tt>, then the results are
5590 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5591
5592<h5>Example:</h5>
5593<pre>
5594 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5595 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5596</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5597
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5598</div>
5599
5600<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5601<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5602 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5603</h4>
5604
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5605<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5606
5607<h5>Syntax:</h5>
5608<pre>
5609 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5610</pre>
5611
5612<h5>Overview:</h5>
5613<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]5614 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5615
5616<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5617<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5618 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5619 a <a href="#t_floating">floating point</a> type to cast it to. The source
5620 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5621
5622<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5623<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5624 <a href="#t_floating">floating point</a> type to a larger
5625 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5626 used to make a <i>no-op cast</i> because it always changes bits. Use
5627 <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]5628
5629<h5>Example:</h5>
5630<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5631 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5632 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5633</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5635</div>
5636
5637<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5638<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5639 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5640</h4>
5641
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5642<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5643
5644<h5>Syntax:</h5>
5645<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5646 &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]5647</pre>
5648
5649<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5650<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5651 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5652
5653<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5654<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5655 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5656 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5657 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5658 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5659
5660<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5661<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5662 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5663 towards zero) unsigned integer value. If the value cannot fit
5664 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5665
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5666<h5>Example:</h5>
5667<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5668 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5669 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5670 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5671</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5672
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5673</div>
5674
5675<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5676<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5677 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5678</h4>
5679
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5680<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5681
5682<h5>Syntax:</h5>
5683<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5684 &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]5685</pre>
5686
5687<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5688<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5689 <a href="#t_floating">floating point</a> <tt>value</tt> to
5690 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5691
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5692<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5694 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5695 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5696 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5697 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5698
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5699<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5700<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5701 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5702 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5703 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5704
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5705<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5706<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5707 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5708 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5709 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5710</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5712</div>
5713
5714<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5715<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5716 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5717</h4>
5718
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5719<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5720
5721<h5>Syntax:</h5>
5722<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5723 &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]5724</pre>
5725
5726<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5727<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5728 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5729
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5730<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5731<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]5732 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5733 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5734 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5735 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5736
5737<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5738<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5739 integer quantity and converts it to the corresponding floating point
5740 value. If the value cannot fit in the floating point value, the results are
5741 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5742
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5743<h5>Example:</h5>
5744<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5745 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5746 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5747</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5748
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5749</div>
5750
5751<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5752<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5753 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5754</h4>
5755
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5756<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5757
5758<h5>Syntax:</h5>
5759<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5760 &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]5761</pre>
5762
5763<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5765 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5766
5767<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5768<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]5769 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5770 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5771 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5772 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5773
5774<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5775<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5776 quantity and converts it to the corresponding floating point value. If the
5777 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5778
5779<h5>Example:</h5>
5780<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5781 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5782 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5783</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5784
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5785</div>
5786
5787<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5788<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5789 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5790</h4>
5791
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5792<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5793
5794<h5>Syntax:</h5>
5795<pre>
5796 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5797</pre>
5798
5799<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5800<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5801 pointers <tt>value</tt> to
5802 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5803
5804<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5805<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5806 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5807 pointers, and a type to cast it to
5808 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5809 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5810
5811<h5>Semantics:</h5>
5812<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5813 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5814 truncating or zero extending that value to the size of the integer type. If
5815 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5816 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5817 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5818 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5819
5820<h5>Example:</h5>
5821<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5822 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5823 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5824 %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]5825</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5826
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5827</div>
5828
5829<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5830<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5831 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5832</h4>
5833
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5834<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5835
5836<h5>Syntax:</h5>
5837<pre>
5838 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5839</pre>
5840
5841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5842<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5843 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5844
5845<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5846<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5847 value to cast, and a type to cast it to, which must be a
5848 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5849
5850<h5>Semantics:</h5>
5851<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5852 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5853 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5854 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5855 than the size of a pointer then a zero extension is done. If they are the
5856 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5857
5858<h5>Example:</h5>
5859<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5860 %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]5861 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5862 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5863 %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]5864</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5866</div>
5867
5868<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5869<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5870 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5871</h4>
5872
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5873<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5874
5875<h5>Syntax:</h5>
5876<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5877 &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]5878</pre>
5879
5880<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5881<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5882 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5883
5884<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5885<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5886 non-aggregate first class value, and a type to cast it to, which must also be
5887 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5888 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5889 identical. If the source type is a pointer, the destination type must also be
5890 a pointer. This instruction supports bitwise conversion of vectors to
5891 integers and to vectors of other types (as long as they have the same
5892 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5893
5894<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5895<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5896 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5897 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5898 stored to memory and read back as type <tt>ty2</tt>.
5899 Pointer (or vector of pointers) types may only be converted to other pointer
5900 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5901 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5902 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5903
5904<h5>Example:</h5>
5905<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5906 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5907 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5908 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5909 %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]5910</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5911
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5912</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5914</div>
5915
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5916<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5917<h3>
5918 <a name="otherops">Other Operations</a>
5919</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5920
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5921<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922
5923<p>The instructions in this category are the "miscellaneous" instructions, which
5924 defy better classification.</p>
5925
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5926<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5927<h4>
5928 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5929</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5931<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5932
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5933<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934<pre>
5935 &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]5936</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5937
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5938<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5939<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5940 boolean values based on comparison of its two integer, integer vector,
5941 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5943<h5>Arguments:</h5>
5944<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5945 the condition code indicating the kind of comparison to perform. It is not a
5946 value, just a keyword. The possible condition code are:</p>
5947
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5948<ol>
5949 <li><tt>eq</tt>: equal</li>
5950 <li><tt>ne</tt>: not equal </li>
5951 <li><tt>ugt</tt>: unsigned greater than</li>
5952 <li><tt>uge</tt>: unsigned greater or equal</li>
5953 <li><tt>ult</tt>: unsigned less than</li>
5954 <li><tt>ule</tt>: unsigned less or equal</li>
5955 <li><tt>sgt</tt>: signed greater than</li>
5956 <li><tt>sge</tt>: signed greater or equal</li>
5957 <li><tt>slt</tt>: signed less than</li>
5958 <li><tt>sle</tt>: signed less or equal</li>
5959</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5961<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5962 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5963 typed. They must also be identical types.</p>
5964
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5965<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5966<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5967 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5968 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]5969 result, as follows:</p>
5970
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5971<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5972 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5973 <tt>false</tt> otherwise. No sign interpretation is necessary or
5974 performed.</li>
5975
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5976 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5977 <tt>false</tt> otherwise. No sign interpretation is necessary or
5978 performed.</li>
5979
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5980 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5981 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5982
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5983 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5984 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5985 to <tt>op2</tt>.</li>
5986
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5987 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5988 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5989
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5990 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5992
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5993 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5994 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5995
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5996 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5997 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5998 to <tt>op2</tt>.</li>
5999
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6000 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
6002
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6003 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6005</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6006
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6007<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008 values are compared as if they were integers.</p>
6009
6010<p>If the operands are integer vectors, then they are compared element by
6011 element. The result is an <tt>i1</tt> vector with the same number of elements
6012 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6013
6014<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6015<pre>
6016 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6017 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
6018 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
6019 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
6020 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
6021 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6022</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6023
6024<p>Note that the code generator does not yet support vector types with
6025 the <tt>icmp</tt> instruction.</p>
6026
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6027</div>
6028
6029<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6030<h4>
6031 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
6032</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6033
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6034<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6035
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6036<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6037<pre>
6038 &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]6039</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6040
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6042<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
6043 values based on comparison of its operands.</p>
6044
6045<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]6046(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6047
6048<p>If the operands are floating point vectors, then the result type is a vector
6049 of boolean with the same number of elements as the operands being
6050 compared.</p>
6051
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6052<h5>Arguments:</h5>
6053<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6054 the condition code indicating the kind of comparison to perform. It is not a
6055 value, just a keyword. The possible condition code are:</p>
6056
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6057<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6058 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6059 <li><tt>oeq</tt>: ordered and equal</li>
6060 <li><tt>ogt</tt>: ordered and greater than </li>
6061 <li><tt>oge</tt>: ordered and greater than or equal</li>
6062 <li><tt>olt</tt>: ordered and less than </li>
6063 <li><tt>ole</tt>: ordered and less than or equal</li>
6064 <li><tt>one</tt>: ordered and not equal</li>
6065 <li><tt>ord</tt>: ordered (no nans)</li>
6066 <li><tt>ueq</tt>: unordered or equal</li>
6067 <li><tt>ugt</tt>: unordered or greater than </li>
6068 <li><tt>uge</tt>: unordered or greater than or equal</li>
6069 <li><tt>ult</tt>: unordered or less than </li>
6070 <li><tt>ule</tt>: unordered or less than or equal</li>
6071 <li><tt>une</tt>: unordered or not equal</li>
6072 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6073 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6074</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6075
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6076<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077 <i>unordered</i> means that either operand may be a QNAN.</p>
6078
6079<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
6080 a <a href="#t_floating">floating point</a> type or
6081 a <a href="#t_vector">vector</a> of floating point type. They must have
6082 identical types.</p>
6083
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6084<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]6085<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6086 according to the condition code given as <tt>cond</tt>. If the operands are
6087 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]6088 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6089 follows:</p>
6090
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6091<ol>
6092 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6093
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6094 <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]6095 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6096
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6097 <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]6098 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6099
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6100 <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]6101 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6102
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6103 <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]6104 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6105
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6106 <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]6107 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6108
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6109 <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]6110 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6111
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6112 <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]6113
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6114 <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]6115 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
6116
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6117 <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]6118 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
6119
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6120 <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]6121 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6122
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6123 <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]6124 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6125
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6126 <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]6127 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6128
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6129 <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]6130 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6131
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]6132 <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]6133
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6134 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6135</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6136
6137<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6138<pre>
6139 &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]6140 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6141 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6142 &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]6143</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6144
6145<p>Note that the code generator does not yet support vector types with
6146 the <tt>fcmp</tt> instruction.</p>
6147
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]6148</div>
6149
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6150<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6151<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6152 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6153</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6154
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6155<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6156
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6157<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6158<pre>
6159 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6160</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6161
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6162<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6163<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6164 SSA graph representing the function.</p>
6165
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167<p>The type of the incoming values is specified with the first type field. After
6168 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6169 one pair for each predecessor basic block of the current block. Only values
6170 of <a href="#t_firstclass">first class</a> type may be used as the value
6171 arguments to the PHI node. Only labels may be used as the label
6172 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6173
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6174<p>There must be no non-phi instructions between the start of a basic block and
6175 the PHI instructions: i.e. PHI instructions must be first in a basic
6176 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6177
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6178<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6179 occur on the edge from the corresponding predecessor block to the current
6180 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6181 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]6182
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6183<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6184<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6185 specified by the pair corresponding to the predecessor basic block that
6186 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6187
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6188<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]6189<pre>
6190Loop: ; Infinite loop that counts from 0 on up...
6191 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6192 %nextindvar = add i32 %indvar, 1
6193 br label %Loop
6194</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6195
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]6196</div>
6197
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6198<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6199<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6200 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6201</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6202
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6203<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6204
6205<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6206<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]6207 &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>
6208
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6209 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6210</pre>
6211
6212<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6213<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6214 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6215
6216
6217<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6218<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6219 values indicating the condition, and two values of the
6220 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6221 vectors and the condition is a scalar, then entire vectors are selected, not
6222 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6223
6224<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6225<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6226 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6227
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6228<p>If the condition is a vector of i1, then the value arguments must be vectors
6229 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6230
6231<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6232<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6233 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6234</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6235
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6236</div>
6237
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6238<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6239<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6240 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6241</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6242
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6243<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6245<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6246<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6247 &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]6248</pre>
6249
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6250<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6251<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6252
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6253<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6254<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6255
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6256<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6257 <li>The optional "tail" marker indicates that the callee function does not
6258 access any allocas or varargs in the caller. Note that calls may be
6259 marked "tail" even if they do not occur before
6260 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6261 present, the function call is eligible for tail call optimization,
6262 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6263 optimized into a jump</a>. The code generator may optimize calls marked
6264 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6265 sibling call optimization</a> when the caller and callee have
6266 matching signatures, or 2) forced tail call optimization when the
6267 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6268 <ul>
6269 <li>Caller and callee both have the calling
6270 convention <tt>fastcc</tt>.</li>
6271 <li>The call is in tail position (ret immediately follows call and ret
6272 uses value of call or is void).</li>
6273 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6274 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6275 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6276 constraints are met.</a></li>
6277 </ul>
6278 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6279
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6280 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6281 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6282 defaults to using C calling conventions. The calling convention of the
6283 call must match the calling convention of the target function, or else the
6284 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6285
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6286 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6287 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6288 '<tt>inreg</tt>' attributes are valid here.</li>
6289
6290 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6291 type of the return value. Functions that return no value are marked
6292 <tt><a href="#t_void">void</a></tt>.</li>
6293
6294 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6295 being invoked. The argument types must match the types implied by this
6296 signature. This type can be omitted if the function is not varargs and if
6297 the function type does not return a pointer to a function.</li>
6298
6299 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6300 be invoked. In most cases, this is a direct function invocation, but
6301 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6302 to function value.</li>
6303
6304 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6305 signature argument types and parameter attributes. All arguments must be
6306 of <a href="#t_firstclass">first class</a> type. If the function
6307 signature indicates the function accepts a variable number of arguments,
6308 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6309
6310 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6311 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6312 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6313</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6315<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6316<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6317 a specified function, with its incoming arguments bound to the specified
6318 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6319 function, control flow continues with the instruction after the function
6320 call, and the return value of the function is bound to the result
6321 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6323<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6324<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6325 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6326 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6327 %X = tail call i32 @foo() <i>; yields i32</i>
6328 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6329 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6330
6331 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6332 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6333 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6334 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6335 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6336 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6337</pre>
6338
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6339<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6340standard C99 library as being the C99 library functions, and may perform
6341optimizations or generate code for them under that assumption. This is
6342something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6343freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6344
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6345</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6346
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6347<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6348<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6349 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6350</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6351
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6352<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6353
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6354<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6355<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6356 &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]6357</pre>
6358
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6359<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6360<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6361 the "variable argument" area of a function call. It is used to implement the
6362 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6363
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6364<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6365<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6366 argument. It returns a value of the specified argument type and increments
6367 the <tt>va_list</tt> to point to the next argument. The actual type
6368 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6369
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6370<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6371<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6372 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6373 to the next argument. For more information, see the variable argument
6374 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6375
6376<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]6377 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6378 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6379
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6380<p><tt>va_arg</tt> is an LLVM instruction instead of
6381 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6382 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6383
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6384<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6385<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6386
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6387<p>Note that the code generator does not yet fully support va_arg on many
6388 targets. Also, it does not currently support va_arg with aggregate types on
6389 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6391</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6392
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6393<!-- _______________________________________________________________________ -->
6394<h4>
6395 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6396</h4>
6397
6398<div>
6399
6400<h5>Syntax:</h5>
6401<pre>
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6402 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6403 &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]6404
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6405 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6406 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6407</pre>
6408
6409<h5>Overview:</h5>
6410<p>The '<tt>landingpad</tt>' instruction is used by
6411 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6412 system</a> to specify that a basic block is a landing pad &mdash; one where
6413 the exception lands, and corresponds to the code found in the
6414 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6415 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6416 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6417 type <tt>resultty</tt>.</p>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6418
6419<h5>Arguments:</h5>
6420<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6421 function associated with the unwinding mechanism. The optional
6422 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6423
6424<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6425 or <tt>filter</tt> &mdash; and contains the global variable representing the
6426 "type" that may be caught or filtered respectively. Unlike the
6427 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6428 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6429 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6430 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6431
6432<h5>Semantics:</h5>
6433<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6434 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6435 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6436 calling conventions, how the personality function results are represented in
6437 LLVM IR is target specific.</p>
6438
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6439<p>The clauses are applied in order from top to bottom. If two
6440 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sands8d6796b2012-01-13 19:59:16 +0000[diff] [blame]6441 clauses from the calling function are appended to the list of clauses.
6442 When the call stack is being unwound due to an exception being thrown, the
6443 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6444 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6445 unwinding continues further up the call stack.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6446
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6447<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6448
6449<ul>
6450 <li>A landing pad block is a basic block which is the unwind destination of an
6451 '<tt>invoke</tt>' instruction.</li>
6452 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6453 first non-PHI instruction.</li>
6454 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6455 pad block.</li>
6456 <li>A basic block that is not a landing pad block may not include a
6457 '<tt>landingpad</tt>' instruction.</li>
6458 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6459 personality function.</li>
6460</ul>
6461
6462<h5>Example:</h5>
6463<pre>
6464 ;; A landing pad which can catch an integer.
6465 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6466 catch i8** @_ZTIi
6467 ;; A landing pad that is a cleanup.
6468 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6469 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6470 ;; A landing pad which can catch an integer and can only throw a double.
6471 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6472 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6473 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6474</pre>
6475
6476</div>
6477
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6478</div>
6479
6480</div>
6481
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6482<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6483<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6484<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6486<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6487
6488<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6489 well known names and semantics and are required to follow certain
6490 restrictions. Overall, these intrinsics represent an extension mechanism for
6491 the LLVM language that does not require changing all of the transformations
6492 in LLVM when adding to the language (or the bitcode reader/writer, the
6493 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6494
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6495<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6496 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6497 begin with this prefix. Intrinsic functions must always be external
6498 functions: you cannot define the body of intrinsic functions. Intrinsic
6499 functions may only be used in call or invoke instructions: it is illegal to
6500 take the address of an intrinsic function. Additionally, because intrinsic
6501 functions are part of the LLVM language, it is required if any are added that
6502 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6503
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6504<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6505 family of functions that perform the same operation but on different data
6506 types. Because LLVM can represent over 8 million different integer types,
6507 overloading is used commonly to allow an intrinsic function to operate on any
6508 integer type. One or more of the argument types or the result type can be
6509 overloaded to accept any integer type. Argument types may also be defined as
6510 exactly matching a previous argument's type or the result type. This allows
6511 an intrinsic function which accepts multiple arguments, but needs all of them
6512 to be of the same type, to only be overloaded with respect to a single
6513 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6514
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6515<p>Overloaded intrinsics will have the names of its overloaded argument types
6516 encoded into its function name, each preceded by a period. Only those types
6517 which are overloaded result in a name suffix. Arguments whose type is matched
6518 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6519 can take an integer of any width and returns an integer of exactly the same
6520 integer width. This leads to a family of functions such as
6521 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6522 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6523 suffix is required. Because the argument's type is matched against the return
6524 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6525
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6526<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6527 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6528
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6529<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6530<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6531 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6532</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6533
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6534<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6536<p>Variable argument support is defined in LLVM with
6537 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6538 intrinsic functions. These functions are related to the similarly named
6539 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6540
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6541<p>All of these functions operate on arguments that use a target-specific value
6542 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6543 not define what this type is, so all transformations should be prepared to
6544 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6545
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6546<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]6547 instruction and the variable argument handling intrinsic functions are
6548 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6549
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6550<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6551define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6552 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6553 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6554 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6555 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6556
6557 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6558 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6559
6560 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6561 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6562 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6563 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6564 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6565
6566 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6567 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6568 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6569}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6570
6571declare void @llvm.va_start(i8*)
6572declare void @llvm.va_copy(i8*, i8*)
6573declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6574</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6575
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6576<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6577<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6578 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6579</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6580
6581
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6582<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6583
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6584<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585<pre>
6586 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6587</pre>
6588
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6589<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6590<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6591 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]6592
6593<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6594<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]6595
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6596<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6597<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]6598 macro available in C. In a target-dependent way, it initializes
6599 the <tt>va_list</tt> element to which the argument points, so that the next
6600 call to <tt>va_arg</tt> will produce the first variable argument passed to
6601 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6602 need to know the last argument of the function as the compiler can figure
6603 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6605</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6607<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6608<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6609 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6610</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6611
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6612<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6613
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6614<h5>Syntax:</h5>
6615<pre>
6616 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6617</pre>
6618
6619<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6620<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6621 which has been initialized previously
6622 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6623 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6624
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6625<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6626<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]6627
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6628<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6629<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]6630 macro available in C. In a target-dependent way, it destroys
6631 the <tt>va_list</tt> element to which the argument points. Calls
6632 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6633 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6634 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6635
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6636</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6637
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6638<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6639<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6640 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6641</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6642
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6643<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6644
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6645<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6646<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6647 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6648</pre>
6649
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6650<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6651<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6652 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6653
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6654<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6655<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]6656 The second argument is a pointer to a <tt>va_list</tt> element to copy
6657 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6658
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6659<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6660<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]6661 macro available in C. In a target-dependent way, it copies the
6662 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6663 element. This intrinsic is necessary because
6664 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6665 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6666
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6667</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6668
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6669</div>
6670
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6671<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6672<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6673 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6674</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6675
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6676<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6677
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6678<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6679Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6680intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6681roots on the stack</a>, as well as garbage collector implementations that
6682require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6683barriers. Front-ends for type-safe garbage collected languages should generate
6684these intrinsics to make use of the LLVM garbage collectors. For more details,
6685see <a href="GarbageCollection.html">Accurate Garbage Collection with
6686LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6688<p>The garbage collection intrinsics only operate on objects in the generic
6689 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6690
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6691<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6692<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6693 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6694</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6695
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6696<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6697
6698<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6699<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6700 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6701</pre>
6702
6703<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6704<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]6705 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6706
6707<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6708<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6709 root pointer. The second pointer (which must be either a constant or a
6710 global value address) contains the meta-data to be associated with the
6711 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6712
6713<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6714<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]6715 location. At compile-time, the code generator generates information to allow
6716 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6717 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6718 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6719
6720</div>
6721
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6722<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6723<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6724 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6725</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6726
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6727<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6728
6729<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6730<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6731 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6732</pre>
6733
6734<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6735<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6736 locations, allowing garbage collector implementations that require read
6737 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6738
6739<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6740<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]6741 allocated from the garbage collector. The first object is a pointer to the
6742 start of the referenced object, if needed by the language runtime (otherwise
6743 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6744
6745<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6746<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6747 instruction, but may be replaced with substantially more complex code by the
6748 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6749 may only be used in a function which <a href="#gc">specifies a GC
6750 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6751
6752</div>
6753
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6754<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6755<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6756 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6757</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6759<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6760
6761<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6762<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6763 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6764</pre>
6765
6766<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6767<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6768 locations, allowing garbage collector implementations that require write
6769 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6770
6771<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6772<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]6773 object to store it to, and the third is the address of the field of Obj to
6774 store to. If the runtime does not require a pointer to the object, Obj may
6775 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6776
6777<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6778<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6779 instruction, but may be replaced with substantially more complex code by the
6780 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6781 may only be used in a function which <a href="#gc">specifies a GC
6782 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6783
6784</div>
6785
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6786</div>
6787
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6788<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6789<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6790 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6791</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6792
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6793<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6794
6795<p>These intrinsics are provided by LLVM to expose special features that may
6796 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6797
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6798<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6799<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6800 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6801</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6802
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6803<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6804
6805<h5>Syntax:</h5>
6806<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6807 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6808</pre>
6809
6810<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6811<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6812 target-specific value indicating the return address of the current function
6813 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6814
6815<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6816<p>The argument to this intrinsic indicates which function to return the address
6817 for. Zero indicates the calling function, one indicates its caller, etc.
6818 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6819
6820<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6821<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6822 indicating the return address of the specified call frame, or zero if it
6823 cannot be identified. The value returned by this intrinsic is likely to be
6824 incorrect or 0 for arguments other than zero, so it should only be used for
6825 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6826
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6827<p>Note that calling this intrinsic does not prevent function inlining or other
6828 aggressive transformations, so the value returned may not be that of the
6829 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6830
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6831</div>
6832
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6833<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6834<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6835 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6836</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6837
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6838<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6839
6840<h5>Syntax:</h5>
6841<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6842 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6843</pre>
6844
6845<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6846<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6847 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6848
6849<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6850<p>The argument to this intrinsic indicates which function to return the frame
6851 pointer for. Zero indicates the calling function, one indicates its caller,
6852 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6853
6854<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6855<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6856 indicating the frame address of the specified call frame, or zero if it
6857 cannot be identified. The value returned by this intrinsic is likely to be
6858 incorrect or 0 for arguments other than zero, so it should only be used for
6859 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6860
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6861<p>Note that calling this intrinsic does not prevent function inlining or other
6862 aggressive transformations, so the value returned may not be that of the
6863 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6864
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6865</div>
6866
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6867<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6868<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6869 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6870</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6871
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6872<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6873
6874<h5>Syntax:</h5>
6875<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6876 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6877</pre>
6878
6879<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6880<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6881 of the function stack, for use
6882 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6883 useful for implementing language features like scoped automatic variable
6884 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6885
6886<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6887<p>This intrinsic returns a opaque pointer value that can be passed
6888 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6889 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6890 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6891 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6892 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6893 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6894
6895</div>
6896
6897<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6898<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6899 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6900</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6901
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6902<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6903
6904<h5>Syntax:</h5>
6905<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6906 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6907</pre>
6908
6909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6911 the function stack to the state it was in when the
6912 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6913 executed. This is useful for implementing language features like scoped
6914 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6915
6916<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917<p>See the description
6918 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6919
6920</div>
6921
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6922<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6923<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6924 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6925</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6926
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6927<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6928
6929<h5>Syntax:</h5>
6930<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6931 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]6932</pre>
6933
6934<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6935<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6936 insert a prefetch instruction if supported; otherwise, it is a noop.
6937 Prefetches have no effect on the behavior of the program but can change its
6938 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6939
6940<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6942 specifier determining if the fetch should be for a read (0) or write (1),
6943 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6944 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6945 specifies whether the prefetch is performed on the data (1) or instruction (0)
6946 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6947 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6948
6949<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6950<p>This intrinsic does not modify the behavior of the program. In particular,
6951 prefetches cannot trap and do not produce a value. On targets that support
6952 this intrinsic, the prefetch can provide hints to the processor cache for
6953 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6954
6955</div>
6956
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6957<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6958<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6959 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6960</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6961
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6962<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6963
6964<h5>Syntax:</h5>
6965<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6966 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6967</pre>
6968
6969<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6970<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6971 Counter (PC) in a region of code to simulators and other tools. The method
6972 is target specific, but it is expected that the marker will use exported
6973 symbols to transmit the PC of the marker. The marker makes no guarantees
6974 that it will remain with any specific instruction after optimizations. It is
6975 possible that the presence of a marker will inhibit optimizations. The
6976 intended use is to be inserted after optimizations to allow correlations of
6977 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6978
6979<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6981
6982<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6984 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6985
6986</div>
6987
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6988<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6989<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6990 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6991</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6992
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6993<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6994
6995<h5>Syntax:</h5>
6996<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6997 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6998</pre>
6999
7000<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7001<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
7002 counter register (or similar low latency, high accuracy clocks) on those
7003 targets that support it. On X86, it should map to RDTSC. On Alpha, it
7004 should map to RPCC. As the backing counters overflow quickly (on the order
7005 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7006
7007<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7008<p>When directly supported, reading the cycle counter should not modify any
7009 memory. Implementations are allowed to either return a application specific
7010 value or a system wide value. On backends without support, this is lowered
7011 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]7012
7013</div>
7014
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7015</div>
7016
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7017<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7018<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7019 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7020</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7021
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7022<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7023
7024<p>LLVM provides intrinsics for a few important standard C library functions.
7025 These intrinsics allow source-language front-ends to pass information about
7026 the alignment of the pointer arguments to the code generator, providing
7027 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7028
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7029<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7030<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7031 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7032</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7033
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7034<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7035
7036<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7037<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]7038 integer bit width and for different address spaces. Not all targets support
7039 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7041<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7042 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]7043 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7044 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]7045 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7046</pre>
7047
7048<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7049<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7050 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7051
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7053 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7054 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7055
7056<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7058<p>The first argument is a pointer to the destination, the second is a pointer
7059 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7060 number of bytes to copy, the fourth argument is the alignment of the
7061 source and destination locations, and the fifth is a boolean indicating a
7062 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7063
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7064<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]7065 then the caller guarantees that both the source and destination pointers are
7066 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7067
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7068<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7069 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
7070 The detailed access behavior is not very cleanly specified and it is unwise
7071 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7072
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7073<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7074
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7075<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
7076 source location to the destination location, which are not allowed to
7077 overlap. It copies "len" bytes of memory over. If the argument is known to
7078 be aligned to some boundary, this can be specified as the fourth argument,
7079 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7080
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]7081</div>
7082
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7083<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7084<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7085 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7086</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7087
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7088<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7089
7090<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7091<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]7092 width and for different address space. Not all targets support all bit
7093 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7094
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7095<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7096 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]7097 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7098 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]7099 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7100</pre>
7101
7102<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7103<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
7104 source location to the destination location. It is similar to the
7105 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
7106 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7109 intrinsics do not return a value, takes extra alignment/isvolatile arguments
7110 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7111
7112<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7113
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7114<p>The first argument is a pointer to the destination, the second is a pointer
7115 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7116 number of bytes to copy, the fourth argument is the alignment of the
7117 source and destination locations, and the fifth is a boolean indicating a
7118 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7119
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7120<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]7121 then the caller guarantees that the source and destination pointers are
7122 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]7123
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7124<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7125 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7126 The detailed access behavior is not very cleanly specified and it is unwise
7127 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7128
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7129<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7130
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7131<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7132 source location to the destination location, which may overlap. It copies
7133 "len" bytes of memory over. If the argument is known to be aligned to some
7134 boundary, this can be specified as the fourth argument, otherwise it should
7135 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7136
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]7137</div>
7138
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7139<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7140<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7141 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7142</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7143
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7144<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7145
7146<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]7147<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]7148 width and for different address spaces. However, not all targets support all
7149 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7150
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7151<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7152 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7153 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]7154 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]7155 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7156</pre>
7157
7158<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7159<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7160 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7161
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7162<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7163 intrinsic does not return a value and takes extra alignment/volatile
7164 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7165
7166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167<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]7168 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]7170 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7171
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7172<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]7173 then the caller guarantees that the destination pointer is aligned to that
7174 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7175
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]7176<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7177 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7178 The detailed access behavior is not very cleanly specified and it is unwise
7179 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]7180
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7181<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7182<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7183 at the destination location. If the argument is known to be aligned to some
7184 boundary, this can be specified as the fourth argument, otherwise it should
7185 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7186
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]7187</div>
7188
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7189<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7190<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7191 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7192</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7193
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7194<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7195
7196<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7197<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7198 floating point or vector of floating point type. Not all targets support all
7199 types however.</p>
7200
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7201<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7202 declare float @llvm.sqrt.f32(float %Val)
7203 declare double @llvm.sqrt.f64(double %Val)
7204 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7205 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7206 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7207</pre>
7208
7209<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7211 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7212 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7213 behavior for negative numbers other than -0.0 (which allows for better
7214 optimization, because there is no need to worry about errno being
7215 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]7216
7217<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7218<p>The argument and return value are floating point numbers of the same
7219 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7220
7221<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7222<p>This function returns the sqrt of the specified operand if it is a
7223 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7224
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7225</div>
7226
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7227<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7228<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7229 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7230</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7231
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7232<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7233
7234<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7235<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7236 floating point or vector of floating point type. Not all targets support all
7237 types however.</p>
7238
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7239<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7240 declare float @llvm.powi.f32(float %Val, i32 %power)
7241 declare double @llvm.powi.f64(double %Val, i32 %power)
7242 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7243 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7244 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7245</pre>
7246
7247<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7249 specified (positive or negative) power. The order of evaluation of
7250 multiplications is not defined. When a vector of floating point type is
7251 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7252
7253<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7254<p>The second argument is an integer power, and the first is a value to raise to
7255 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7256
7257<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7258<p>This function returns the first value raised to the second power with an
7259 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7260
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7261</div>
7262
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7263<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7264<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7265 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7266</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7267
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7268<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7269
7270<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7271<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7272 floating point or vector of floating point type. Not all targets support all
7273 types however.</p>
7274
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7275<pre>
7276 declare float @llvm.sin.f32(float %Val)
7277 declare double @llvm.sin.f64(double %Val)
7278 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7279 declare fp128 @llvm.sin.f128(fp128 %Val)
7280 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7281</pre>
7282
7283<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7284<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7285
7286<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7287<p>The argument and return value are floating point numbers of the same
7288 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7289
7290<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7291<p>This function returns the sine of the specified operand, returning the same
7292 values as the libm <tt>sin</tt> functions would, and handles error conditions
7293 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7294
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7295</div>
7296
7297<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7298<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7299 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7300</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7301
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7302<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7303
7304<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7305<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7306 floating point or vector of floating point type. Not all targets support all
7307 types however.</p>
7308
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7309<pre>
7310 declare float @llvm.cos.f32(float %Val)
7311 declare double @llvm.cos.f64(double %Val)
7312 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7313 declare fp128 @llvm.cos.f128(fp128 %Val)
7314 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7315</pre>
7316
7317<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7318<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7319
7320<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7321<p>The argument and return value are floating point numbers of the same
7322 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7323
7324<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7325<p>This function returns the cosine of the specified operand, returning the same
7326 values as the libm <tt>cos</tt> functions would, and handles error conditions
7327 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7328
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7329</div>
7330
7331<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7332<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7333 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7334</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7335
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7336<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7337
7338<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7339<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7340 floating point or vector of floating point type. Not all targets support all
7341 types however.</p>
7342
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7343<pre>
7344 declare float @llvm.pow.f32(float %Val, float %Power)
7345 declare double @llvm.pow.f64(double %Val, double %Power)
7346 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7347 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7348 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7349</pre>
7350
7351<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7353 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7354
7355<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7356<p>The second argument is a floating point power, and the first is a value to
7357 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7358
7359<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7360<p>This function returns the first value raised to the second power, returning
7361 the same values as the libm <tt>pow</tt> functions would, and handles error
7362 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7363
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7364</div>
7365
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7366<!-- _______________________________________________________________________ -->
7367<h4>
7368 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7369</h4>
7370
7371<div>
7372
7373<h5>Syntax:</h5>
7374<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7375 floating point or vector of floating point type. Not all targets support all
7376 types however.</p>
7377
7378<pre>
7379 declare float @llvm.exp.f32(float %Val)
7380 declare double @llvm.exp.f64(double %Val)
7381 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7382 declare fp128 @llvm.exp.f128(fp128 %Val)
7383 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7384</pre>
7385
7386<h5>Overview:</h5>
7387<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7388
7389<h5>Arguments:</h5>
7390<p>The argument and return value are floating point numbers of the same
7391 type.</p>
7392
7393<h5>Semantics:</h5>
7394<p>This function returns the same values as the libm <tt>exp</tt> functions
7395 would, and handles error conditions in the same way.</p>
7396
7397</div>
7398
7399<!-- _______________________________________________________________________ -->
7400<h4>
7401 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7402</h4>
7403
7404<div>
7405
7406<h5>Syntax:</h5>
7407<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7408 floating point or vector of floating point type. Not all targets support all
7409 types however.</p>
7410
7411<pre>
7412 declare float @llvm.log.f32(float %Val)
7413 declare double @llvm.log.f64(double %Val)
7414 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7415 declare fp128 @llvm.log.f128(fp128 %Val)
7416 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7417</pre>
7418
7419<h5>Overview:</h5>
7420<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7421
7422<h5>Arguments:</h5>
7423<p>The argument and return value are floating point numbers of the same
7424 type.</p>
7425
7426<h5>Semantics:</h5>
7427<p>This function returns the same values as the libm <tt>log</tt> functions
7428 would, and handles error conditions in the same way.</p>
7429
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7430</div>
7431
7432<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7433<h4>
7434 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7435</h4>
7436
7437<div>
7438
7439<h5>Syntax:</h5>
7440<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7441 floating point or vector of floating point type. Not all targets support all
7442 types however.</p>
7443
7444<pre>
7445 declare float @llvm.fma.f32(float %a, float %b, float %c)
7446 declare double @llvm.fma.f64(double %a, double %b, double %c)
7447 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7448 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7449 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7450</pre>
7451
7452<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7453<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7454 operation.</p>
7455
7456<h5>Arguments:</h5>
7457<p>The argument and return value are floating point numbers of the same
7458 type.</p>
7459
7460<h5>Semantics:</h5>
7461<p>This function returns the same values as the libm <tt>fma</tt> functions
7462 would.</p>
7463
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7464</div>
7465
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7466</div>
7467
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7468<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7469<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7470 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7471</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7472
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7473<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7474
7475<p>LLVM provides intrinsics for a few important bit manipulation operations.
7476 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7477
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7478<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7479<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7480 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7481</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7482
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7483<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7484
7485<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7486<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7487 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7488
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7489<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7490 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7491 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7492 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7493</pre>
7494
7495<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7496<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7497 values with an even number of bytes (positive multiple of 16 bits). These
7498 are useful for performing operations on data that is not in the target's
7499 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7500
7501<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7502<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7503 and low byte of the input i16 swapped. Similarly,
7504 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7505 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7506 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7507 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7508 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7509 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7510
7511</div>
7512
7513<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7514<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7515 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7516</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7517
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7518<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7519
7520<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7521<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]7522 width, or on any vector with integer elements. Not all targets support all
7523 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7524
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7525<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7526 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7527 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7528 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7529 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7530 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7531 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]7532</pre>
7533
7534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7535<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7536 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7537
7538<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7539<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]7540 integer type, or a vector with integer elements.
7541 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7542
7543<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7544<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7545 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7546
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7547</div>
7548
7549<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7550<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7551 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7552</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7553
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7554<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7555
7556<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7557<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]7558 integer bit width, or any vector whose elements are integers. Not all
7559 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7560
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7561<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7562 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7563 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7564 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7565 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7566 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7567 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]7568</pre>
7569
7570<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7571<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7572 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7573
7574<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7575<p>The first argument is the value to be counted. This argument may be of any
7576 integer type, or a vectory with integer element type. The return type
7577 must match the first argument type.</p>
7578
7579<p>The second argument must be a constant and is a flag to indicate whether the
7580 intrinsic should ensure that a zero as the first argument produces a defined
7581 result. Historically some architectures did not provide a defined result for
7582 zero values as efficiently, and many algorithms are now predicated on
7583 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7584
7585<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7586<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7587 zeros in a variable, or within each element of the vector.
7588 If <tt>src == 0</tt> then the result is the size in bits of the type of
7589 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7590 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7591
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7592</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7593
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7594<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7595<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7596 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7597</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7598
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7599<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7600
7601<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7602<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]7603 integer bit width, or any vector of integer elements. Not all targets
7604 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7605
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7606<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7607 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7608 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7609 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7610 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7611 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7612 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]7613</pre>
7614
7615<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7616<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7617 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7618
7619<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7620<p>The first argument is the value to be counted. This argument may be of any
7621 integer type, or a vectory with integer element type. The return type
7622 must match the first argument type.</p>
7623
7624<p>The second argument must be a constant and is a flag to indicate whether the
7625 intrinsic should ensure that a zero as the first argument produces a defined
7626 result. Historically some architectures did not provide a defined result for
7627 zero values as efficiently, and many algorithms are now predicated on
7628 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7629
7630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7631<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7632 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7633 If <tt>src == 0</tt> then the result is the size in bits of the type of
7634 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7635 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7636
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7637</div>
7638
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7639</div>
7640
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7641<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7642<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7643 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7644</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7645
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7646<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7647
7648<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7649
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7650<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7651<h4>
7652 <a name="int_sadd_overflow">
7653 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7654 </a>
7655</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7656
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7657<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7658
7659<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7660<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]7661 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7662
7663<pre>
7664 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7665 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7666 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7667</pre>
7668
7669<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7670<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7671 a signed addition of the two arguments, and indicate whether an overflow
7672 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7673
7674<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7675<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]7676 be of integer types of any bit width, but they must have the same bit
7677 width. The second element of the result structure must be of
7678 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7679 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7680
7681<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7682<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7683 a signed addition of the two variables. They return a structure &mdash; the
7684 first element of which is the signed summation, and the second element of
7685 which is a bit specifying if the signed summation resulted in an
7686 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7687
7688<h5>Examples:</h5>
7689<pre>
7690 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7691 %sum = extractvalue {i32, i1} %res, 0
7692 %obit = extractvalue {i32, i1} %res, 1
7693 br i1 %obit, label %overflow, label %normal
7694</pre>
7695
7696</div>
7697
7698<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7699<h4>
7700 <a name="int_uadd_overflow">
7701 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7702 </a>
7703</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7704
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7705<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7706
7707<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7708<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]7709 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7710
7711<pre>
7712 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7713 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7714 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7715</pre>
7716
7717<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7718<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7719 an unsigned addition of the two arguments, and indicate whether a carry
7720 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7721
7722<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7723<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]7724 be of integer types of any bit width, but they must have the same bit
7725 width. The second element of the result structure must be of
7726 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7727 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7728
7729<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7730<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7731 an unsigned addition of the two arguments. They return a structure &mdash;
7732 the first element of which is the sum, and the second element of which is a
7733 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7734
7735<h5>Examples:</h5>
7736<pre>
7737 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7738 %sum = extractvalue {i32, i1} %res, 0
7739 %obit = extractvalue {i32, i1} %res, 1
7740 br i1 %obit, label %carry, label %normal
7741</pre>
7742
7743</div>
7744
7745<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7746<h4>
7747 <a name="int_ssub_overflow">
7748 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7749 </a>
7750</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7751
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7752<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7753
7754<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7755<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]7756 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7757
7758<pre>
7759 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7760 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7761 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7762</pre>
7763
7764<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7765<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7766 a signed subtraction of the two arguments, and indicate whether an overflow
7767 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7768
7769<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7770<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]7771 be of integer types of any bit width, but they must have the same bit
7772 width. The second element of the result structure must be of
7773 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7774 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7775
7776<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7777<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7778 a signed subtraction of the two arguments. They return a structure &mdash;
7779 the first element of which is the subtraction, and the second element of
7780 which is a bit specifying if the signed subtraction resulted in an
7781 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7782
7783<h5>Examples:</h5>
7784<pre>
7785 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7786 %sum = extractvalue {i32, i1} %res, 0
7787 %obit = extractvalue {i32, i1} %res, 1
7788 br i1 %obit, label %overflow, label %normal
7789</pre>
7790
7791</div>
7792
7793<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7794<h4>
7795 <a name="int_usub_overflow">
7796 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7797 </a>
7798</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7799
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7800<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7801
7802<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7803<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]7804 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7805
7806<pre>
7807 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7808 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7809 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7810</pre>
7811
7812<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7813<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7814 an unsigned subtraction of the two arguments, and indicate whether an
7815 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7816
7817<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7818<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]7819 be of integer types of any bit width, but they must have the same bit
7820 width. The second element of the result structure must be of
7821 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7822 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7823
7824<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7825<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7826 an unsigned subtraction of the two arguments. They return a structure &mdash;
7827 the first element of which is the subtraction, and the second element of
7828 which is a bit specifying if the unsigned subtraction resulted in an
7829 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7830
7831<h5>Examples:</h5>
7832<pre>
7833 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7834 %sum = extractvalue {i32, i1} %res, 0
7835 %obit = extractvalue {i32, i1} %res, 1
7836 br i1 %obit, label %overflow, label %normal
7837</pre>
7838
7839</div>
7840
7841<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7842<h4>
7843 <a name="int_smul_overflow">
7844 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7845 </a>
7846</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7847
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7848<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7849
7850<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7851<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]7852 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7853
7854<pre>
7855 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7856 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7857 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7858</pre>
7859
7860<h5>Overview:</h5>
7861
7862<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7863 a signed multiplication of the two arguments, and indicate whether an
7864 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7865
7866<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7867<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]7868 be of integer types of any bit width, but they must have the same bit
7869 width. The second element of the result structure must be of
7870 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7871 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7872
7873<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7874<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7875 a signed multiplication of the two arguments. They return a structure &mdash;
7876 the first element of which is the multiplication, and the second element of
7877 which is a bit specifying if the signed multiplication resulted in an
7878 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7879
7880<h5>Examples:</h5>
7881<pre>
7882 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7883 %sum = extractvalue {i32, i1} %res, 0
7884 %obit = extractvalue {i32, i1} %res, 1
7885 br i1 %obit, label %overflow, label %normal
7886</pre>
7887
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7888</div>
7889
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7890<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7891<h4>
7892 <a name="int_umul_overflow">
7893 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7894 </a>
7895</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7896
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7897<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7898
7899<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7900<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]7901 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7902
7903<pre>
7904 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7905 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7906 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7907</pre>
7908
7909<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7910<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7911 a unsigned multiplication of the two arguments, and indicate whether an
7912 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7913
7914<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7915<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]7916 be of integer types of any bit width, but they must have the same bit
7917 width. The second element of the result structure must be of
7918 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7919 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7920
7921<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7922<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7923 an unsigned multiplication of the two arguments. They return a structure
7924 &mdash; the first element of which is the multiplication, and the second
7925 element of which is a bit specifying if the unsigned multiplication resulted
7926 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7927
7928<h5>Examples:</h5>
7929<pre>
7930 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7931 %sum = extractvalue {i32, i1} %res, 0
7932 %obit = extractvalue {i32, i1} %res, 1
7933 br i1 %obit, label %overflow, label %normal
7934</pre>
7935
7936</div>
7937
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7938</div>
7939
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7940<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7941<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7942 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7943</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7944
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7945<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7946
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7947<p>Half precision floating point is a storage-only format. This means that it is
7948 a dense encoding (in memory) but does not support computation in the
7949 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7950
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7951<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7952 value as an i16, then convert it to float with <a
7953 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7954 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7955 double etc). To store the value back to memory, it is first converted to
7956 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7957 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7958 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7959
7960<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7961<h4>
7962 <a name="int_convert_to_fp16">
7963 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7964 </a>
7965</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7966
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7967<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7968
7969<h5>Syntax:</h5>
7970<pre>
7971 declare i16 @llvm.convert.to.fp16(f32 %a)
7972</pre>
7973
7974<h5>Overview:</h5>
7975<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7976 a conversion from single precision floating point format to half precision
7977 floating point format.</p>
7978
7979<h5>Arguments:</h5>
7980<p>The intrinsic function contains single argument - the value to be
7981 converted.</p>
7982
7983<h5>Semantics:</h5>
7984<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7985 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7986 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7987 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7988
7989<h5>Examples:</h5>
7990<pre>
7991 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7992 store i16 %res, i16* @x, align 2
7993</pre>
7994
7995</div>
7996
7997<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7998<h4>
7999 <a name="int_convert_from_fp16">
8000 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
8001 </a>
8002</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8003
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8004<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8005
8006<h5>Syntax:</h5>
8007<pre>
8008 declare f32 @llvm.convert.from.fp16(i16 %a)
8009</pre>
8010
8011<h5>Overview:</h5>
8012<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
8013 a conversion from half precision floating point format to single precision
8014 floating point format.</p>
8015
8016<h5>Arguments:</h5>
8017<p>The intrinsic function contains single argument - the value to be
8018 converted.</p>
8019
8020<h5>Semantics:</h5>
8021<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]8022 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]8023 precision floating point format. The input half-float value is represented by
8024 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8025
8026<h5>Examples:</h5>
8027<pre>
8028 %a = load i16* @x, align 2
8029 %res = call f32 @llvm.convert.from.fp16(i16 %a)
8030</pre>
8031
8032</div>
8033
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8034</div>
8035
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]8036<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8037<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8038 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8039</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8040
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8041<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8042
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8043<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
8044 prefix), are described in
8045 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
8046 Level Debugging</a> document.</p>
8047
8048</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]8049
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8050<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8051<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8052 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8053</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8054
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8055<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8056
8057<p>The LLVM exception handling intrinsics (which all start with
8058 <tt>llvm.eh.</tt> prefix), are described in
8059 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
8060 Handling</a> document.</p>
8061
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8062</div>
8063
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8064<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8065<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8066 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8067</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8068
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8069<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8070
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8071<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]8072 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
8073 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8074 function pointer lacking the nest parameter - the caller does not need to
8075 provide a value for it. Instead, the value to use is stored in advance in a
8076 "trampoline", a block of memory usually allocated on the stack, which also
8077 contains code to splice the nest value into the argument list. This is used
8078 to implement the GCC nested function address extension.</p>
8079
8080<p>For example, if the function is
8081 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
8082 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
8083 follows:</p>
8084
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]8085<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8086 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
8087 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8088 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
8089 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]8090 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8091</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8092
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8093<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
8094 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8095
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8096<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8097<h4>
8098 <a name="int_it">
8099 '<tt>llvm.init.trampoline</tt>' Intrinsic
8100 </a>
8101</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8102
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8103<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8104
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8105<h5>Syntax:</h5>
8106<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8107 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]8108</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8109
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8110<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]8111<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
8112 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8113
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8114<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8115<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
8116 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
8117 sufficiently aligned block of memory; this memory is written to by the
8118 intrinsic. Note that the size and the alignment are target-specific - LLVM
8119 currently provides no portable way of determining them, so a front-end that
8120 generates this intrinsic needs to have some target-specific knowledge.
8121 The <tt>func</tt> argument must hold a function bitcast to
8122 an <tt>i8*</tt>.</p>
8123
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8124<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8125<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]8126 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8127 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8128 which can be <a href="#int_trampoline">bitcast (to a new function) and
8129 called</a>. The new function's signature is the same as that of
8130 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8131 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8132 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8133 with the same argument list, but with <tt>nval</tt> used for the missing
8134 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8135 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8136 to the returned function pointer is undefined.</p>
8137</div>
8138
8139<!-- _______________________________________________________________________ -->
8140<h4>
8141 <a name="int_at">
8142 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8143 </a>
8144</h4>
8145
8146<div>
8147
8148<h5>Syntax:</h5>
8149<pre>
8150 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8151</pre>
8152
8153<h5>Overview:</h5>
8154<p>This performs any required machine-specific adjustment to the address of a
8155 trampoline (passed as <tt>tramp</tt>).</p>
8156
8157<h5>Arguments:</h5>
8158<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8159 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8160 </a>.</p>
8161
8162<h5>Semantics:</h5>
8163<p>On some architectures the address of the code to be executed needs to be
8164 different to the address where the trampoline is actually stored. This
8165 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8166 after performing the required machine specific adjustments.
8167 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8168 executed</a>.
8169</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8170
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8171</div>
8172
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8173</div>
8174
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]8175<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8176<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8177 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8178</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8179
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8180<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8181
8182<p>This class of intrinsics exists to information about the lifetime of memory
8183 objects and ranges where variables are immutable.</p>
8184
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8185<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8186<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8187 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8188</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8189
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8190<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8191
8192<h5>Syntax:</h5>
8193<pre>
8194 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8195</pre>
8196
8197<h5>Overview:</h5>
8198<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8199 object's lifetime.</p>
8200
8201<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8202<p>The first argument is a constant integer representing the size of the
8203 object, or -1 if it is variable sized. The second argument is a pointer to
8204 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8205
8206<h5>Semantics:</h5>
8207<p>This intrinsic indicates that before this point in the code, the value of the
8208 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]8209 never be used and has an undefined value. A load from the pointer that
8210 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8211 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8212
8213</div>
8214
8215<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8216<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8217 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8218</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8219
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8220<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8221
8222<h5>Syntax:</h5>
8223<pre>
8224 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8225</pre>
8226
8227<h5>Overview:</h5>
8228<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8229 object's lifetime.</p>
8230
8231<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8232<p>The first argument is a constant integer representing the size of the
8233 object, or -1 if it is variable sized. The second argument is a pointer to
8234 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8235
8236<h5>Semantics:</h5>
8237<p>This intrinsic indicates that after this point in the code, the value of the
8238 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8239 never be used and has an undefined value. Any stores into the memory object
8240 following this intrinsic may be removed as dead.
8241
8242</div>
8243
8244<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8245<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8246 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8247</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8248
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8249<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8250
8251<h5>Syntax:</h5>
8252<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8253 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8254</pre>
8255
8256<h5>Overview:</h5>
8257<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8258 a memory object will not change.</p>
8259
8260<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8261<p>The first argument is a constant integer representing the size of the
8262 object, or -1 if it is variable sized. The second argument is a pointer to
8263 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8264
8265<h5>Semantics:</h5>
8266<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8267 the return value, the referenced memory location is constant and
8268 unchanging.</p>
8269
8270</div>
8271
8272<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8273<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8274 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8275</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8276
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8277<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8278
8279<h5>Syntax:</h5>
8280<pre>
8281 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8282</pre>
8283
8284<h5>Overview:</h5>
8285<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8286 a memory object are mutable.</p>
8287
8288<h5>Arguments:</h5>
8289<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8290 The second argument is a constant integer representing the size of the
8291 object, or -1 if it is variable sized and the third argument is a pointer
8292 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8293
8294<h5>Semantics:</h5>
8295<p>This intrinsic indicates that the memory is mutable again.</p>
8296
8297</div>
8298
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8299</div>
8300
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8301<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8302<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8303 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8304</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8305
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8306<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8307
8308<p>This class of intrinsics is designed to be generic and has no specific
8309 purpose.</p>
8310
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8311<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8312<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8313 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8314</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8315
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8316<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8317
8318<h5>Syntax:</h5>
8319<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8320 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]8321</pre>
8322
8323<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8324<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8325
8326<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8327<p>The first argument is a pointer to a value, the second is a pointer to a
8328 global string, the third is a pointer to a global string which is the source
8329 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8330
8331<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8332<p>This intrinsic allows annotation of local variables with arbitrary strings.
8333 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8334 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8335 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8336
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8337</div>
8338
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8339<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8340<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8341 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8342</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8343
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8344<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8345
8346<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8347<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8348 any integer bit width.</p>
8349
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8350<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8351 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8352 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8353 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8354 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8355 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]8356</pre>
8357
8358<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8359<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8360
8361<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8362<p>The first argument is an integer value (result of some expression), the
8363 second is a pointer to a global string, the third is a pointer to a global
8364 string which is the source file name, and the last argument is the line
8365 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8366
8367<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8368<p>This intrinsic allows annotations to be put on arbitrary expressions with
8369 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8370 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8371 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8372
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8373</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8374
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8375<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8376<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8377 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8378</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8379
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8380<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8381
8382<h5>Syntax:</h5>
8383<pre>
8384 declare void @llvm.trap()
8385</pre>
8386
8387<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8388<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8389
8390<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8391<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8392
8393<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8394<p>This intrinsics is lowered to the target dependent trap instruction. If the
8395 target does not have a trap instruction, this intrinsic will be lowered to
8396 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8397
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8398</div>
8399
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8400<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8401<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8402 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8403</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8404
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8405<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8406
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8407<h5>Syntax:</h5>
8408<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8409 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8410</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8411
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8412<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8413<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8414 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8415 ensure that it is placed on the stack before local variables.</p>
8416
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8417<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8418<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8419 arguments. The first argument is the value loaded from the stack
8420 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8421 that has enough space to hold the value of the guard.</p>
8422
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8423<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8424<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8425 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8426 stack. This is to ensure that if a local variable on the stack is
8427 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8428 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8429 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8430 function.</p>
8431
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8432</div>
8433
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8434<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8435<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8436 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8437</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8438
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8439<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8440
8441<h5>Syntax:</h5>
8442<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8443 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8444 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8445</pre>
8446
8447<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8448<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8449 the optimizers to determine at compile time whether a) an operation (like
8450 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8451 runtime check for overflow isn't necessary. An object in this context means
8452 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8453
8454<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8455<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8456 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8457 is a boolean 0 or 1. This argument determines whether you want the
8458 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8459 1, variables are not allowed.</p>
8460
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8461<h5>Semantics:</h5>
8462<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8463 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8464 depending on the <tt>type</tt> argument, if the size cannot be determined at
8465 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8466
8467</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8468<!-- _______________________________________________________________________ -->
8469<h4>
8470 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8471</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8472
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8473<div>
8474
8475<h5>Syntax:</h5>
8476<pre>
8477 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8478 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8479</pre>
8480
8481<h5>Overview:</h5>
8482<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8483 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8484
8485<h5>Arguments:</h5>
8486<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8487 argument is a value. The second argument is an expected value, this needs to
8488 be a constant value, variables are not allowed.</p>
8489
8490<h5>Semantics:</h5>
8491<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8492</div>
8493
8494</div>
8495
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8496</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8497<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8498<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8499<address>
8500 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8501 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8502 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8503 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8504
8505 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8506 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8507 Last modified: $Date$
8508</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8510</body>
8511</html>